Energy Efficiency and Building Science News
Over the past two years, the International Code Council’s (ICC) family of I-Codes have been undergoing development for the 2021 editions of the International Building Code (IBC), International Residential Code (IRC), and International Energy Conservation Code (IECC), among others. Documentation and results of 2018 Group A and 2019 Group B code development processes are found at here.
With the recent conclusion of the final stage of the ICC code development process for the 2021 I-Codes (pending confirmation of on-line voting results for Group B), it is now time to begin assessing what happened in the realm of energy efficiency and building science advancements. A tiny sample of advancements are noted below with more details to come in future articles.
- Significant improvements in the thermal performance (R-values and U-factors) of building envelopes for commercial and residential buildings governed by the IECC.
- Overhaul and update of water vapor control provisions for the IBC and IRC, including better organization, recognition of smart vapor retarders, and expanded guidance for appropriate use of continuous insulation to control water vapor. Explore the links below to read more about vapor barrier science and installation guidance.
- Expanded options for wood frame wall R-value compliance including cavity insulation only, cavity plus continuous insulation (hybrid assembly), and continuous insulation only (i.e., “perfect wall”) options. Again, explore the links below to read more about “perfect” and “hybrid” walls.
- Improved and clarified requirements for water-resistive barrier and drainage space to mitigate moisture problems experienced by wood-frame walls clad with conventional Portland cement stucco. For example, read this article on how exterior walls need to breathe.
- A new climate zone map for the U.S.
- Improved Energy Rating Index (ERI) scores for homes – also known as HERS scores.
- Improved air leakage criteria and testing requirements for commercial and residential buildings. For more information on air-barriers and air-leakage control, refer to the Air Barrier Topical Library on continuousinsulation.org.
- Additional energy efficiency packages and “points” options for commercial and residential construction.
- Revised “above-grade wall” definition to include floor edges to ensure continuity of building envelope thermal performance at assembly intersections (i.e., mitigate thermal bridges).
- Clarification of “energy code math” for proper addition of insulation components for R-value compliance. For example, addressing why an R-25 wall is not equal to an R-20+5ci.
- Provision for use of renewable energy use and design and construction of net zero energy buildings (also with provisions to prevent misuse of renewable energy as a means to trade-off energy efficiency or conservation).
These expected changes for the 2021 editions of the IBC, IRC, and IECC codes are only the tip of the iceberg. We look forward to highlighting various proposals and their details in future EEBS News articles.
For additional information, please review the following articles, as well as the previous videos in this series:
Perfect Wall Articles
- Creating the ‘Perfect Wall’: Simplifying Water Vapor Retarder Requirements to Control Moisture
- Perfect Walls are Perfect, and Hybrid Walls Perfectly Good
- Wood Framed Wall Insulation Calculator Explained
- New Wall Design Calculator for Commercial Energy Code Compliance
- Energy Code Math Lesson: Why an R-25 Wall is Not Equal to a R-20+5ci
- Continuous Insulation Solves Energy Code Math Problem
- Fear Building Envelopes No More with This Website & Videos
- Thermodynamics Simplified Heat Flows from Warm to Cold
- Moisture Flow Drives Water Induced Problems
- Video: How the 'Perfect Wall' Solves Environmental Diversity
- Video: How Important Is Your WRB?
- Video: A Reliably Perfect Wall Anywhere
- Video: The Best Wall We Know How to Make
- Video: How to Insulate with Steel Studs
- Video: Thermal Bridging and Steel Studs
- Video: Better Residential Energy Performance with Continuous Insulation
- Video: How to (Not) Ruin a Perfectly Good Wall
- Video: Tar Paper and Continuous Insulation? No Problem!
- Video: Do CI and WRBs Go Together?
- Video: Assess Your 'Perfect Wall' Using Control Layers
- Air Barriers: Small Details Make Big Difference
- How Exterior Walls Breathe
- Air-Sealing the Lid: A High Performance Solution
- What Caused the Air Barrier Industry to Develop?
- What’s the Big Deal with Air Leakage?
- How To: Air-Sealing Simplified
- Retrofit Concepts Improve Energy Efficiency
- Why Air Sealing a Garage Wall is Important
- Choosing the Right Air Barrier Material for Your Project
Billions of dollars are spent on building envelope failures annually — a largely preventable problem if building mock-ups — “crash test dummies for building enclosures”— are specified.
That’s the word from Brian Stroik, manager of the building envelope solutions team at Tremco Incorporated.
Stroik, who presented a seminar on the importance of building envelope mock-ups recently at the Buildings Show in Toronto, said tested mock-ups are critical because every building is unique. Even a chain restaurant or retail outlet with practically identical designs in the same city will face variations that impact the envelope.
The building’s site orientation, the trades involved, and the weather play significant roles in envelope performance.
One of the benefits of tested mock-ups is when time is tight, they can help speed up construction sequencing and they educate installers on proper assembly procedures, Stroik added.
“I’m not saying a mock-up will guarantee you a leak-free building but I’m saying it will help you get closer (to that goal).”
Brian Stroik, manager of the building envelope solutions team at Tremco Incorporated says building mock-ups can help project’s avoid costly mistakes in the future.
While 93 per cent of tested mock-ups fail the first time, according to 2009 National Testing Lab results, building science experts say the real percentage of failures is even higher. That is a good thing, however, said Stroik because a mock-up “is supposed to be a learning experience.”
He told the seminar audience that architects specify products from several manufacturers that comprise an envelope design but “there’s no guarantee that they will all work (together) unless they are tested (together).”
He said there can be many different wall configurations on a single project (more than 100 in some cases) so “tested performance mock-ups” should be in the architectural specifications.
Explanations for the tests and why they are necessary in specs serve as a form of checks and balances, he said, recalling a project where an architect included specs for air duct testing in a building enclosure mock-up just because he thought they qualified as an air test. “He didn’t know what he was talking about.”
While mock-ups take time to build, test, deconstruct, reconstruct and retest, over the span of a project they can save money and time, Stroik said.
He also said they don’t have to be expensive or complex. “A little mock-up” for a window with a silicone transition versus sealant from window to wall is cheap to do and helps installers understand construction sequencing.
He said the time has never been more important to do tested mock-ups because the shortage of skilled labour in Canada and the U.S. gives project owners little guarantee that the selected installers will apply the envelope correctly.
While testing specified mock-ups is typically conducted by general contractors or construction managers, Stroik said, but the costs for materials and installation are transferred down to the trades. “If it is not in the spec…not in the (architectural) details that is when it gets really expensive because guys see it as a change order.”
The products selected for Building Design+Construction’s annual 101 Top Products report are determined by you, our readers. From security doors to metal ceilings, fabric ducts to rainscreen wall systems, linear drains to bacteria-killing LED lighting, these are the products that appeared in the pages of the magazine over the past 12 months that readers wanted to learn more about. The products were selected based on the number of reader service inquiries. BD+C editors selected a few of our favorites as well (marked “Editors' Picks”). Below are the Building Envelope products selected.MIRAIA FIBER CEMENT PANELS
Miraia fiber cement panels are available with this reflective, high-gloss finish. Three color options: Glacier, Onyx (pictured), and Snow. Offers the luster of metal at a competitive price point, according to the maker. The panels are factory sealed on six sides and cover 8.88 sf per panel. Dimensions: 17-7/8 inches high, 71-9/16 inches long, and 5/8-inch thick. Concealed clips and fasteners provide a clean, uninterrupted appearance.STARTER BOARDS AT LIFESTYLE COMMUNITIES
Project: Lifestyle Communities, Nashville, Tenn. Problem: The design called for eight-inch EPS shapes around the windows, which meant back-wrapping these termination points in the field would have been near impossible.
Solution: Dryvit Acrocore Starter Boards were integral to the project at these termination points. The boards are uniformly machine-coated to produce a product that is three times harder and stronger than hand-applied starter boards. Installing pre-coated starter boards was three times faster than manual back wrapping.ROOF, WALL INSULATION AT LAX
Project: Los Angeles International Airport concourse. Problem: The project needed an insulation solution to help meet the California Green Building Standards Code Mandatory and Tier 1 requirements.
Solution: The team used more than 215,000 sf of Atlas EnergyShield CGF Pro for wall insulation and 500,000 sf of ACFoam-II for roof insulation due to their low VOC emissions and performance. The EnergyShield GCF Pro wall insulation is vapor permeable and composed of a Class A fire-rated (NFPA 285 compliant), closed-cell polyiso rigid foam core faced with a high-performance coated glass facer on the front and back. The ACFoam roof panels needed to be custom made (2x8 feet) in order to meet the architect’s design needs. On the team: Gensler, gkkworks, Turner Construction, PCL Construction.OPTIM-R
This rigid vacuum insulation panel features a microporous core, which is evacuated, encased, and sealed in a gas–tight envelope. The result is an ultra–thin (20mm to 50mm) insulation product with up to five times better thermal efficiency than commonly available insulation. R-values from R-29 to R-60. Applications: roof assemblies, balconies, and terraces.VACUSEAL VENT SECURED ROOF SYSTEM
The VacuSeal Vent Secured Roofing System uses special vents that harness the wind to lock roof membranes in place. Negative pressure venting pulls air and moisture out from under the membrane to maintain insulation dryness and R-value. VacuSeal reduces installation time and minimizes the need for traditional fastening methods, which reduces the amount of glue, ballast, or fasteners a project requires. The vents are made from UV-resistant PVC, contain no moving parts, and require no penetrations.PAC-CLAD AT CADE MUSEUM
Project: Cade Museum for Creativity + Invention, Gainesville, Fla. Problem: The museum needed a creative and eye-catching design.
Solution: 11,400 sf of 22-gauge PAC-CLAD corrugated straight panels and 6,000 sf of PAC-CLAD corrugated curved panels, all in a Galvalume Plus finish, were installed throughout the museum’s exploded-circle plan. The design creates a sense of movement, which is reinforced by the running lines of the structure’s corrugated metal wall and roof panels. On the team: GWWO Architects, Thornton Tomasetti (SE).EN-V METAL PANEL SYSTEM
This dry joint, pressure-equalized aluminum panel rainscreen system starts at just $11.95/sf for panels, one of the lowest prices on the market, according to its maker. Twenty-one panel dimensions (ranging from 18x48 inches to 120x24 inches), combined with vertical and horizontal stacked and staggered panel layout options, maximize design flexibility. Formed corners and trim pieces are available, as are custom colors. Material is .080-inch aluminum with fluoropolymer finish.DELTA-STRATUS SA
To help combat deterioration from UV exposure during the construction process, Dörken Systems developed Delta-Stratus SA, the industry’s only vapor-permeable air- and water-resistive barrier with a fourth layer of added UV protection. The barrier features two outer layers of high-strength polypropylene fabric, a vapor-permeable, watertight polymeric middle layer, and an inner layer made of an acrylic UV-resistant coating. Delta-Stratus SA was tested using real-world conditions to ensure it retains optimum water-penetration resistance, air tightness, and building integrity. It is fully adhered, from back to edge, allowing for simple, straightforward application without fasteners.TYPAR DRAINABLE WRAP
EDITORS' PICK: This building wrap features a layer of multi-directional polypropylene fibers that diverts bulk water from exterior wall cavities. It sheds more bulk water than traditional wraps, protecting structures from moisture, mold, and rot. It can be installed in any direction without affecting performance. Offers six months of UV resistance. Has a Class A fire rating and drainage efficiency of 94.8% (per ASTM E2273). Five-foot-wide rolls come in 100-foot lengths.PASSIVE RAINSCREEN SYSTEM
Modified wood products manufacturer Kebony introduced a clip system that makes it easy for contractors to create a rainscreen cladding using the company’s wood siding. The system supplants predrilling of cladding, reduces installation and labor costs, and eliminates potential moisture penetration from face fasteners. It can be applied over most exterior and interior envelope design types, including directly over mineral fiber exterior insulation.THERMALSAFE STRIATED IMP
EDITORS' PICK: Metl-Span’s ThermalSafe insulated metal panel is now available with a Striated exterior profile. The metal panel features the company’s LockGuard interlocking side joint to achieve a one-, two-, or three-hour fire resistance rating for walls and 11/2 hours for ceilings. ThermalSafe’s core is made from non-combustible structural and non-toxic mineral wool boards processed to maximize compressive strength. The core insulating properties are 3.61 R per inch. Panels are 42 inches wide and available in thicknesses of 3, 4, 5, 6, 7 or 8 inches.PERM-A-BARRIER VPS 30
EDITORS' PICK: The Perm-A-Barrier VPS 30 air barrier from GCP Applied Technologies is a primerless, permeable, self-adhering air barrier membrane. It features advanced adhesive to enable primerless installation on concrete, CMU, or exterior gypsum, cutting installation time by up to 35% compared to traditional systems, according to the maker. Designed for wall assemblies that require vapor permeability. Just peel off the release liner and adhere the air barrier to the substrate.
The government’s ban on using combustible materials in external walls of high-rise residential towers could stymie the use of innovative products such as photovoltaic panels and green walls, according to a leading designer.
The ban was introduced a year ago in response to the Grenfell disaster in 2017 in which 72 people lost their lives.
But Rob Buck (pictured), façade design associate at Arup, told last month’s Building Live panel debate on façade safety that the current testing regime was limited in scope and failed to consider how a particular product was going to be used.
Buck said he feared the blocking of materials such as photovoltaics “because they use laminated glass within the spandrel panel, and green facades, since they are in effect combustible products”.
He wanted to see a risk-based approach “based on sound fire engineering knowledge.
“And if that means we need to develop more understanding and more testing, then that’s where we should go,” Buck added.
Buck warned the current analysis regime for façades was limited. “The BS 8414 test [which assesses the fire performance of an external cladding system] is tied specifically with rain-screen products and there’s a debate in the industry whether that is applicable.
“I think there is a test that we should be able to employ to allow us to further learn about façades working in fire,” he said.
Another speaker told the gathering in London that government restrictions would lead materials manufacturers to be more innovative.
Russell Curtis, founding director of architect RCKa, said some manufacturers of cross-laminated timber were already looking at non-combustible versions of their product.
“They have to. It’s an existential problem. If you’re a CLT manufacturer you can’t sell your product to anyone who’s building reasonably tall buildings.
“Out of this there will be innovation around façade solutions and materials that will be positive, but it will take time.”
BASF and an affiliate of Lone Star, a global private equity firm, signed a purchase agreement for the acquisition of BASF’s Construction Chemicals business. The purchase price on a cash and debt-free basis is €3.17 billion. The transaction is expected to close in the third quarter of 2020, subject to the approval of the relevant competition authorities.
“Our aim was to find a new home for our Construction Chemicals business where it can leverage its full potential,” said Saori Dubourg, member of the Board of Executive Directors of BASF SE and responsible for the Construction Chemicals business. “Under the umbrella of Lone Star, the Construction Chemicals team can focus on a growth path with an industry-specific approach.”
“BASF’s Construction Chemicals business fits very well with our portfolio, complementing our investments in the construction materials industry,” said Donald Quintin, President of Europe at Lone Star. “We highly value the industry-wide recognized knowledge and competence of BASF’s Construction Chemicals experts, backed by a strong track record in innovative products and a compelling R&D pipeline. We look forward to jointly pursuing a growth-oriented business approach.”
With more than 7,000 employees, BASF’s Construction Chemicals business operates production sites and sales offices in more than 60 countries and generated sales of about €2.5 billion in 2018.
The signing of the agreement has immediate effect on the reporting of BASF Group. Retroactively as of January 1, 2019, sales and earnings of the Construction Chemicals division are no longer included in sales, EBITDA and EBIT before special items of BASF Group. The prior-year figures will be restated accordingly (BASF Group sales 2018 restated: €60.2 billion; EBITDA 2018 restated: €8,970 million; EBIT before special items 2018 restated: €6,281 million). Until closing, earnings will be presented in the income after taxes of BASF Group as a separate item (“Income after taxes from discontinued operations”).
The U.S. Department of Energy (DOE) has published a final determination of energy savings for the 2018 International Energy Conservation Code (IECC), affirming that the updated code will increase energy efficiency in residential buildings. DOE analysis indicates that buildings meeting the 2018 IECC (as compared to the previous 2015 edition) would result in national energy savings of approximately:
- 1.97% energy cost
- 1.91% source energy
- 1.68% site energy
DOE is required to issue its determination following the publication of an updated edition of the IECC. More information, including supplemental energy and cost savings analysis, is available via the DOE Building Energy Codes Program.
Energy efficiency is a diverse and immensely powerful toolkit that has saved hundreds of billions of dollars in energy costs while preventing sharp increases in greenhouse gas emissions, but progress is now at risk of stalling, a report finds. The first-of-its-kind report from the Alliance to Save Energy, the American Council for an Energy-Efficient Economy, and the Business Council for Sustainable Energy provides a consolidated analysis of the sweeping impacts of energy efficiency investments, policies, and innovation and the potential energy savings still ahead across a variety of sectors including residential and commercial buildings, industry, and transportation.
The Energy Efficiency Impact Report quantifies the scale of U.S. efficiency investments made over decades and their many impacts, ranging from energy savings, job growth, and reduced carbon emissions to public health and worker productivity savings. It notes these investments since 1980 have prevented a 60% increase in energy consumption and carbon emissions and are responsible for half of the carbon dioxide emissions reductions in the U.S. power sector since 2005. It also highlights the six most impactful policies – fuel economy standards, appliance and equipment energy efficiency standards, ENERGY STAR, utility sector efficiency programs, federal research and development, and building energy codes – which have saved an estimated 25 quadrillion BTUs of energy in 2017, equal to 23% of total U.S. energy use.
Despite these successes, the biggest opportunities remain ahead, and growth in smarter technologies and more responsive energy management could lead to new savings opportunities. Energy efficiency improvements using existing technologies alone could deliver more than 40% of the carbon reductions globally to meet Paris Agreement climate targets, and fully half of emissions reductions needed in the U.S. But the U.S. is not on this track to achieve these reductions, and even risks sliding backward, the report says.
While federal spending on energy efficiency has increased slightly from 2016 to 2018, estimated total domestic energy efficiency investment levels have fallen by 18%, the report warns. Energy intensity in the U.S. – the ratio of energy use to economic output – worsened slightly in 2018.
“There’s no question that greater energy and carbon reductions are technically and economically feasible through more ambitious action on energy efficiency, the question is will we treat this with the urgency it deserves,” said Clay Nesler, president of the Alliance to Save Energy. “This report shows that energy efficiency has been, and must continue to be, the leading solution to address the worsening climate emergency while simultaneously growing our economy and improving the health of our communities.”
“Energy efficiency can slash US energy use and greenhouse gas emissions by 50% by 2050, getting us halfway to our climate goals,” said Steve Nadel, executive director of the American Council for an Energy-Efficient Economy. “Given the urgency of the climate threat, we need robust investments in energy-efficient appliances, buildings, vehicles, and industrial plants.”
“Energy efficiency is the enabler for optimization and integration of clean energy technologies, and we need to scale it urgently to meet our energy and environmental objectives,” said Lisa Jacobson, president of the Business Council for Sustainable Energy. “Scaling energy efficiency is also critical to enhancing the resilience of energy systems. Recent disasters have strained energy infrastructure and buildings, costing billions. Upfront investments in energy efficiency not only decrease emissions but mitigate extreme weather impacts.”
The new report uses 54 indicators to quantify energy efficiency impacts, drawing primarily on data from federal and international sources. It examines efficiency progress in a wide variety of sectors including utilities, buildings, industry, and transportation, and explores the impacts of policy and other market tools used to incentivize energy efficiency.
The full report will be published at: http://energyefficiencyimpact.org/
Below are the top ten most read Energy Efficiency & Building Science News headlines of the fourth quarter of 2019:
- 7 Insulation Alternatives to Fiberglass Batts
- How to Attach Cladding Over up to 4" Thick Foam Sheathing
- Illustrations: Housewrap and Drip Edging Done Right
- Let’s Admit Building Science Is Complicated, Here’s Why
- Blower Door: Friend or Foe?
- Code Definitions Are Important, SBCA Helps on FRTW
- Rigid Foam & Tape Can Be an Effective Insulation Strategy
- 2021 I-Codes Represent Major Advance in Vapor Retarders & CI
- Why Polyiso Insulation Can Be a Great WRB
- Choose Good Building Practice When it Comes to Thermal Bridging
The U.S. House Ways and Means Committee issued a draft version of the GREEN Act. The bill extends and modifies several tax in addition to creating completely new deductions as well. Of note, is the bills extension of the §45L new energy efficient home credit through 2024. The draft legislation states:
“Starting in 2020, the provision expands the maximum credit for eligible new energy efficient homes from $2,000 to $2,500 and makes eligible units with energy expenditures at least 15% below the expenditures of a comparable unit based on the 2018 International Energy Conservation Code standards. It also replaces the eligibility requirements for units eligible for the $1,000 credit to correspond with the Energy Star Labeled Homes program.”
Registration is now open for Roofing Day in D.C. 2020 held April 21-22 in our Nation’s Capital. Unite with roofing professionals from all industry segments throughout the U.S. to advocate for key industry issues, including increased investments in career and technical education programs for the construction sector as well as policies that support the deployment of energy-efficient building technologies and practices.
Registration is $95 for company representatives if you register by February 29, 2020. A room block has been secured at the Marriott Washington Wardman Park. Please make your hotel reservations right away as the room block will sell out. Click “Read More” for event details, hotel reservations, and registration information.
Jack Armstrong, Director of Team Zero and President of ACUMEN, LLC, speaks on trends in the green building industry
GHB: How do you think recent developments have been shaping the industry at large?
Jack Armstrong: Essentially, mutifamily is where it’s at right now. In recent trends we see that urban population and urban centers are growing, the millennials don’t tend to have a lot of money to buy single family homes, and they’re more environmentally minded so multifamily has been that kind of bright stop in all markets moving forward. I think because the multifamily section has been growing just due to demographics – and financing reasons and things like that – it’s also been a bright stop with the “smart money” if you say: going in to running these facilities in an economically judicious fashion. And hence, that’s why we’re seeing some of these sustainability attributes as well as the energy-saving, carbon-saving, and water-saving features start to crop up in multifamily because it appeals to the new younger demographic. But more importantly, typically the groups and developers that invest in multifamily are kind of “smart money” so to speak, and they understand building science; they understand the economics of why these green energy-efficient sustainable buildings cost less to operate. Many of the multifamily situations, sometimes rent includes electricity, sometimes it’s not it just varies, but that’s certainly one of those areas as an owner/operator that affects cost in some of these multifamily facilities. It goes right down to the bottom line, in addition to demographic. Millennials want to have energy efficient homes or be good to the environment
Incentives too, across the nation with codes that have been adopted now. The International Energy Conservation Codes (IECC) – 2012, 2015, 2018 – each of those three-year code cycles have ramped up the performance of what building in general need to do, and states have adopting things like continuous insulation on the outside of the building for helping them perform better as well as good indoor quality and the whole health movement
GHB: We see some developments even exceeding state energy codes like the ABC Green Home Project. Are seeing any similar industry trends?
JA: Without a doubt. If you take California; Title 24 has essentially increased by 50 percent the energy performance requirements starting in January. So they’re 50 percent more restrictive and if you do the math the opposite way, essentially the 2016 California energy code is 100 percent less.
50 percent increase but those older buildings are going to perform at 100 percent less than the mandated level. That’s pretty impressive. I think those are the market forces and when people pencil out the math it works.Say it’s going to cost $40 more per month for the mortgage for an average green home, but they’re going to save $80 per month, so cash flow positive right out of the shoot.
GHB: What other industry trends are you seeing this year, and what do you see as for the rest of 2019?
JA: The organization called The Net Zero Energy Coalition started publishing an inventory of net zero energy projects in the U.S. and Canada back in 2015. We just came out with the third version of it about two months ago. It started in the Pacific Northwest region in about 2010. It has been this mission of trying to illustrate through collection impact a hub or a local spot where people can come to get information on what is the right path to zero; regardless of how you want to get there. We felt like creating an inventory so that people can actually see the uptake in the marketplace. In 2015 there were about 408 projects we were able to find. A year later it went up about 80 percent to something like 740 projects, and then a year later in ’17 it went up again to around 1,100 projects, and this last round we are up to around 1,800 projects. That is a combination of both single family and multifamily units, but what we’ve started to see is that it’s mainly in multifamily and that’s where the real swell in the number of units has come up. In this last round there were about 22,000 units.
We work with Sam Rashkin from the Department of Energy. Sam has been instrumental over the years in energy star homes and then later builder-challenge homes, and now the program that the DOE runs around construction of zero-energy ready homes. Sam has, through his program, encompassed a lot of things for these high-performance structures. They’re energy efficient, they have great air quality – because a tighter home can have problems if you’re not doing things right with the air – but also the need to be durable, and so in working with DOE’s zero-energy ready home program as well as the passive house program, NAHB’s green home program, we started to see there’s a lot of confusion in the market place around green or zero homes. What does zero mean? And we thought the best role for the Net Zero Energy Coalition is to rebrand and call it Team Zero with this notion of getting all the stakeholders that are in this space – whether it’s the HVAC people, the insulation people, individual product manufacturers. Also the different rating system programs, so whether it’s USGBC, Living Building Challenge, local regional programs, cause there’s all these people out there talking and there is what we think is confusion in the market place – you might say green fatigue. We had a think tank and brought over 30 stakeholders together in April of this year out in Golden Colorado in the Denver suburb at the National Renewable Energy Lab, and we invited all these different constituencies including New Building Institute, which has its own inventory of 650 commercial buildings and kind of overlaps with what were doing, and we wanted to not dilute resources. The notion of Team Zero is that it’s a collective group with common messaging and a resource hub. We’re wanting to launch a new Team Zero website and an outreach campaign next year, a consumer awareness campaign around zero to give people directions to show that no matter what level or flavor of zero you want to get to – whether its near zero, net-zero, positive; and also whether its with water or emissions – it can be done. Anyone who has zero in their charter we wanted them to be a part of this network and then the goal of team zero is to be able to direct them to the right resources, education, and paths.
GHB: What work do you personally do within the industry?
JA: Acumen, LLC, is my own consulting company. I spent 24 years with a company called BASF, a chemical company making the ingredients that go into building construction, left in 2013 and formed my own consulting company around sustainable construction and marketing initiatives for the built environment primarily. One of the things I do is run a trade association for panelized construction product – Structural Insulated Panels (SIP) – which are used a lot in energy efficient, sustainable construction just because it’s easy to have really great insulated walls and roofs when you build with these foam/wood panels.
On the board of the Net Zero Energy Coalition are a variety of different people from different parts of manufacturing, government, media and outreach just to try and work together on getting the message out and adding some order and structure to defining what is zero in the market place and how to get there.
GHB: What advice do you give to homebuilder looking to go more green?
JA: The big news is that just in this past inventory that we did we see that there is 59 percent more zero energy ready homes at the end of 2019 than there were at the end of 2018.
The markets growing, it’s big, and builders should get on board and what does that mean? Well it really means educating yourself about how to get there economically and to sell the benefits and attributes. What we are trying to do is show people both the economic and the value proposition of saying, ‘Yeah you may spend a little extra money in the caulking, the ceiling, the insulation of these homes, but they perform well.’ And you have to make sure you get them rated like the HERS rating, because that’s the proof of performance. It’s not just someone saying ‘it’s gonna do it;’ a HERS rater actually went in there and did a blower door test, and we feel like that’s really important because before you add on renewable energy, which is expensive, the more robust you can make the building envelope – the walls, the roof, the floor – the less solar power you need to get to zero, or approach zero. That’s really the message is that there’s a lot of good science, it’s available, it doesn’t have to cost you any more once you get past the learning curve.
California is a perfect example. Zero energy homes are increasing in demand, and your competitors are doing it, there are many products out there doing it so if you’re not on board you’re gonna kind of get left behind. California really shows it; the new law requires that homes perform 50 percent better than they did three years prior in California. That can be a scary notion for builders who aren’t always on the cutting edge.
We like to start with the premise that meeting the current building code is not the path to success. The current building code is the worst building legally allowed by law; that’s like the bottom floor of entry. If you want to future-proof your building and make sure that in three years the building you just built isn’t obsolete according to building codes, you need to be a leader in your industry and be more proactive looking forward. Say like in MPG for a car, if the law says you have at least 15 miles to the gallon and you’re at 16 that’s not a lot to brag about versus being at 20, 30, 40 miles to the gallon. So we’re trying to overlay that into the homeowner experience and the builder experience. Nobody wants to make the biggest investment of their lifetime in something that next year is going to be completely out-of-date, and in fact illegal to build again. There’s a mantra that you hear often: “reduce before you produce.” Reduce the demand or the energy burden of your building or structure before you decide to produce renewable energy. If you can have a really great, well-insulated, non-leaky building that can use 50 percent less energy just because you built it well, well then that’s money that you don’t have to pay into solar panels and you have a return on your investment much faster
GHB: What do you see in the future of green homebuilding?
JA: Team Zero is actually in a growth mode and we’re looking for our sponsors to come on board to help fund this awareness campaign next year. We have a program now with Team Zero founding members and we’re going to have the typical gold, silver, and bronze packaging where people can participate in the organization and really help underwrite the consumer awareness campaign that we hope to do next year in 2020. Then they can actually be Team Zero Founding Members and we actually have some organizations that are willing to do matching funding and things like that to raise our goal, which is about $500,000 per year for three years to fund and underwrite the consumer awareness campaign and really get a great website up and running. Working with our partners around zero energy awareness, we’ll continue to expand the zero energy home inventory survey that we do every year to show people that it really is growing and where and show how people are getting there, what products are they using to get there to make it like an easy recipe for other people to follow. It’s one thing to say that you want a zero energy ready house, but most of the builders and consumers aren’t aware of how to do that so we want to show through this inventory of 22,000 units that exist what is the recipe, whose products are they putting in there to get them to zero so that there’s this proven path of performance to success, and they don’t have to idirate around experimentation they can just follow the path that these great successful builders and developers have already been doing for well over five year. There’s a great website through the Department of Energy’s Zero Energy Ready Home program, it’s called the Tour of Zero, and you can actually go on the website and it has interviews with homeowners who live in zero energy homes, they have the cost of the homes, a year’s worth of energy bills, and even the builder and designer of the home. And there’s also one called the Zero Energy Project, which is really in the Pacific Northwest cataloguing products, partners, programs, and projects that have reached zero energy. The SIP association has also been cataloging projects across the country.
So there’s a lot of resources out there to make it easy for people, but they just don’t know about it, where to go, and there’s so much noise in the marketplace. We want to make is easy and effective for people to follow the footsteps of what other people have already worked out so they don’t have to have such a big learning curve. That’s the role of Team Zero to be a helping hand to guide people to the quickest easiest resources to get hem to zero.
From affordable student housing to high-infill offices, a rapidly accelerating building trend is the proliferation of zero energy buildings. Embracing "deep" energy efficiency, this U.S. DOE Better Buildings webinar highlights projects that prioritize energy efficiency and adding on-site renewable generation to achieve net zero energy use. This webinar discussed financial, technological, and design process innovations that make these projects a reality.
Moderator: Sarah Zaleski, U.S. Department of Energy Speakers: Rachel Bannon-Godfrey, Stantec; Greg Farley, Washington College; Jason Fierko, Ewing Cole
Polyiso is a closed-cell, rigid foam board insulation used primarily on the roofs and walls of offices, health facilities, warehouses, retail and industrial manufacturing facilities and educational institutions. Because of its high thermal performance, it is an important foam sheathing product consideration of energy-aware homebuilders and consumers.
In addition to being a continuous insulation solution, Polyiso can also be used as an effective water-resistive barrier (WRB) system. If you’ve never used Polyiso insulation sheathing in this way, a new online design and installation guide has been created to ensure optimal building performance.
This seven-step guide walks through everything from code considerations to installation best practices. In addition to the online guide, an education presentation is available for download that can be used in conversations and trainings with building designers, installers and code officials.
For more information on Polyiso insulation used as a WRB system, please refer to these resources:
- PIMA Website
- Polyiso Technical Resources
- Polyisocyanurate Products & Accessories Used as a Code Compliant Water-Resistive Barrier (WRB) System
- Water-Resistive Barriers: Assuring Consistent Assembly Water-Penetration Resistance
- Water-Resistive Barriers: Assuring Consistent Assembly Water Penetration Resistance
When builders began to insulate houses in the 1920s and 1930s, the exterior paint began to peel. Many painters concluded that insulation draws moisture and refused to paint a house if it was insulated. By 1938, the problem was common enough that Architectural Record published an article titled “Preventing Condensation in Insulated Structures.” The author, an architect named Tyler Stewart Rogers, argued that insulation was not the problem; indoor humidity was. He proposed a two-part solution: vapor barriers and attic ventilation.
Unfortunately, Rogers jumped to prescriptive solutions without fully understanding the problem, says Bill Rose, research architect at the University of Illinois and one of our country’s most respected building scientists. Rogers didn’t account for the effects of temperature on wood siding, and he didn’t address rain leaking in, which Rose says is “the greatest source of water in building envelopes.”
Vapor barriers and attic ventilation did not stop exterior paint from peeling, much to the delight of generations of asbestos-, aluminum-, and vinyl-siding salesmen. Nonetheless, within five years of Rogers’s article being published, his recommendations had been written into our earliest building codes, and the fledgling discipline of residential building science was off to its rocky start.
Seventy years later, our houses are bigger, more complicated, more airtight, insulated to higher levels, and dependent on ever-pricier fossil-fuel energy. Hence, the stakes of building science—comfort, health, durability, and energy bills—are higher than ever. Despite that, most architects, builders, and code officials still don’t understand moisture movement through houses. To make matters worse, there’s no easy way for them to learn about it.
Building science followed advances in comfort
Our efforts to make homes more comfortable—indoor plumbing, thermal insulation, central heating—and the problems resulting from those efforts gave rise to the first generation of building scientists, though they mostly called themselves engineers.
After World War II, man-made building materials such as plywood and dual-pane windows tightened up our houses, making them less drafty and more comfortable. But the air leaks that existed in houses were not all bad. For one thing, warm air leaking into walls and roofs helped to dry any moisture that was already there, whether from water pipes, humidity, or bad flashing. Perhaps more important, those random air leaks also were ventilating our houses. Fresh air entered houses through leaks (infiltration) around foundations and floors, while stale air exited through holes (exfiltration) in walls and roofs.
Despite those changes, our houses continued to perform reasonably well through the 1960s. We didn’t have major problems with rot or mold. And then in the 1970s, the energy crisis hit.
Building science moves to the forefront
When the cost of heating our homes skyrocketed, so did our motivation to heat them more efficiently. We began to experiment—passive solar, active solar, superinsulation, double walls, Larson trusses, envelope houses—which meant that we had to ask what works, what doesn’t, and why. As a result, scientists became interested in houses.
In 1977, an engineer at Princeton University named Gautam Dutt was crawling through attics to figure out why real houses were losing three to seven times more heat than his models predicted. According to Martin Holladay of Green Building Advisor, his eureka moment occurred when he pulled back some insulation and found a huge air leak through an unsealed utility chase. Dutt is credited with discovering the thermal bypass, which led to the realization that hidden air leaks were a far more serious problem than the obvious ones around windows and doors that had been the focus until then. From that point on, sealing hidden air leaks became a priority in the quest for energy efficiency and lower utility bills. Within a few years, the first blower doors were being sold commercially and used to find air leaks and to test homes for airtightness.
We also had our first catastrophic failures in the 1970s, as some supertight houses became uninhabitable within a year due to mold and rot. Those failures helped us to realize that while tight houses save energy, they also need ventilation. Also during the 1970s, the U.S. Department of Energy was established, and scientists at atomic research labs such as Oak Ridge in Tennessee and Lawrence Berkeley in California began to study houses. Residential building science in the United States was ready to emerge as a serious, formal discipline.
It didn’t happen, though. In the mid-1980s, oil prices dropped, interest in energy efficiency waned, research funding was cut, and residential building science lost critical momentum, at least in the United States. In Canada and many European countries, including Germany and Sweden, interest in building science (Europeans call it building physics) continued unabated, spurred on largely by government funding. In 1983, for instance, the U.S. home-building industry was 20 times bigger than Sweden’s, but the Swedish Council for Building Research spent more than three times more on building research than the U.S. Department of Housing and Urban Development. That same year, the National Research Council Canada published Canada’s first textbook on building science, Building Science for a Cold Climate, by Neil B. Hutcheon and Gustav O.P. Handegord. Nearly 30 years later, an American equivalent still hasn’t been published.
Mold, asthma, and construction defects on the rise
Today, we are on the threshold of another major push for increased airtightness and more insulation in houses. Whether it’s the 2012 International Energy Conservation Code (IECC), Energy Star 3.0, Passive House certification, net-zero houses, or simply the movement to improve the efficiency of existing homes, the result is the same— tighter homes—and it has some experts worried.
Rose Grant is a research architect in the Building Technology Research Unit for State Farm Insurance and a former colleague of Bill Rose’s at the University of Illinois. “I think we are on the cusp of some serious building-science issues,” Grant says, “and mold is the canary in the coal mine.” In 2001, mold claims on homeowners’ policies cost insurance companies $1.3 billion, five times more than in the previous year. In 2002, they more than doubled again, exceeding $3 billion. It’s hard to say what happened after 2002 because most insurance companies began excluding mold from coverage.
In the past, experts argued about whether mold posed a serious health threat, but according to a 2007 study funded by the EPA, “Of the 21.8 million people reported to have asthma in the U.S., approximately 4.6 million cases are estimated to be attributable to dampness and mold exposure in the home.” The same study goes on to say, “The national annual cost of asthma that is attributable to dampness and mold exposure in the home is estimated to be $3.5 billion.” Those are just health costs; they don’t include mold remediation. The authors also estimate that dampness or mold is present in 47% of homes.
Dampness and mold could be signs of a maintenance problem. But a Feb. 10, 2011, article from Bloomberg BusinessWeek reports a doubling of construction defects per housing unit from 2000 through 2005 compared with the previous six years. The article references a 2007 University of Florida study in which 69% of the 17,000 defect claims reviewed were found to be associated with moisture penetration.
You could argue that bad flashing or failure to overlap building paper correctly results from poor workmanship, not a failure to understand building science, but the distinction may not matter. As we move toward higher-performance houses, not only do we have to get the weather-resistive barrier right, but we also have to bring a high level of craftsmanship to it. To do that, everybody involved in construction—frame carpenters, plumbers, electricians, HVAC installers, insulators, roofers, siding crews—needs an understanding of basic building science that just doesn’t exist on most job sites today.
You could argue that bad flashing or failure to overlap building paper correctly results from poor workmanship, not a failure to understand building science, but the distinction may not matter. As we move toward higher-performance houses, not only do we have to get the weather-resistive barrier right, but we also have to bring a high level of craftsmanship to it. To do that, everybody involved in construction—frame carpenters, plumbers, electricians, HVAC installers, insulators, roofers, siding crews—needs an understanding of basic building science that just doesn’t exist on most job sites today.The cost of ignorance
To stay comfortable and to reduce energy costs, we’re adding more and more insulation to our homes and sealing air leaks with a vengeance. Without a thorough understanding of building science, though, you easily can trap moisture in walls and roofs, which can lead to peeling paint, mold, rot, and asthma. Ignore air leaks and you’ll pay a stiff energy penalty year after year.
Building science is not well defined
Building science is still an immature discipline, and its scope is not well defined. The narrowest definition focuses on heat, air, and moisture transfer in the building enclosure because that’s where most of the problems are. The broader definition also includes lighting and daylighting, acoustics, fire prevention, and structure.
Regardless of the definition, one of the most important things that building science brings to residential construction is an emphasis on the house as a system. As houses have become increasingly complicated over the years, so too has the network of specialty trades among which we divvy up construction responsibilities. This division of labor makes it difficult for any one person to monitor how everything works (or doesn’t work) together. For example, an electrician installs the bathroom vent fan, a carpenter cuts in the dryer vent, a kitchen specialist hangs the range hood, an HVAC contractor puts in the furnace, a plumber installs the gas water heater, and a mason builds the chimney. Who’s in charge of the home’s ventilation?
Good building science not only requires that all the parts and pieces of a house work together, but it also demands that they be figured out ahead of time. The person doing the figuring matters less. It can be the architect, the builder, an energy specialist, or even a bona-fide building scientist, assuming you can find one.
Although the terms building science and building scientist are not well defined, they are certainly well used. Joseph Lstiburek, a founder of Building Science Corp. (BSC), an architecture and consulting firm near Boston, is perhaps the person in this country most qualified to call himself a building scientist, but he’s so frustrated by all the people misusing the term that he now refers to himself as an engineer.
For John Straube, a partner of Lstiburek’s at BSC, the dividing line between a person with a basic understanding of building and an actual building scientist is the ability to predict performance before it happens and to explain performance quantitatively afterward. “I would ask that a building scientist be able to calculate or predict things—R-values, heat loss, dew point,” Straube says.
Unfortunately, it’s not easy to become a building scientist. Auburn, Penn State, and the University of Minnesota, among others, all have programs in building science. MIT, USC, and UC Berkeley offer master’s degrees in building science. But, says Lstiburek in his typically candid way, “That’s total crap. They have no connection to real building science.” Eric Burnett, who taught building science for 20 years in Canada, was frustrated during the 10 years he spent trying to establish the program at Penn State. “One of the problems is the failure of current architectural and civil-engineering faculty to embrace the teaching of building science,” Burnett says. “They have other priorities.”
There are people working on the problem, however. The National Institute of Building Sciences has a committee devoted to enhancing education across the United States in building science and technology. Paul Totten, a practicing engineer in Washington D.C., is chairman of that committee. He says, “We’re way behind Canada and almost every European country.” One of the committee’s goals over the next five to ten years is to have “full-scale building-science master’s and Ph.D. programs with some consistency in what’s being taught. Right now, heat, air, and moisture transfer aren’t emphasized enough.”
But even a degree is just the beginning. Straube says, “There’s no way to prove that windows leak based on physics. The way we know windows leak is by experience. It’s dangerous when people learn the physics and don’t have the experience.” If we’re expecting hordes of young building scientists to come pouring out of universities and help us to fix all our houses, we’re going to have to wait awhile.
Architects should be trained in building science
Because the goal of building science is to predict how a house will perform, it makes sense that architects and designers should understand it, but building science isn’t emphasized in most architecture schools. Katrin Klingenberg, a German architect now living in Illinois and the head of the Passive House Institute US, says that when she looked into the level of science training for architects in this country, “I was flat-out shocked.” In Germany, she says, architecture students had to take six courses of building science over two years, with exams. If you didn’t pass the exams in three tries, “you had to go and find yourself a different job.”
Many U.S. architects today are becoming certified Passive House consultants because the nine-day training program includes so much building science. “We’re basically re-educating a whole generation of architects,” Klingenberg says. In fact, Carnegie Mellon University and the University of Oregon are looking to partner with the Passive House Institute US and incorporate parts of its certification program into their curricula.
Rachel Wagner is one architect who has taken the Passive House consultant training. She describes the teaching of building science in architecture schools as “woefully inadequate.” Wagner thinks that part of the solution is to make building science a section of the Architect Registration Examination. “Unless getting your license, your accreditation, depends on it, it’s not going to stick. It’s not going to be taken seriously,” Wagner says.
Despite the fact that architects are involved in few residential projects (maybe 5%), Lstiburek thinks the key to improving knowledge of building science is to fix architectural education. “Architects divorced themselves from the technology of construction,” he says. “If they were doing their jobs, I’d be out of business.” He believes that if you start with the architects, the rest of the industry will follow.
Is builder licensing the answer?
Producing more building scientists and educating architects in building science, however important, will not change the way houses are built. To do that, builders need to be educated. Pat Huelman, director of the Cold Climate Housing Program at the University of Minnesota, says, “We could have the best design, the best specs, we could have the right mousetrap, but if the person building it doesn’t understand what it’s supposed to do, it may not work when you’re done.” Paul Totten agrees. “The folks actually building the buildings need to be very deep in this subject,” he says. “Just making some minor errors in the field may cost you all of the performance that you should have gotten out of the building.”
At least some people in Oregon think the answer is builder licensing with a continuing-education requirement that includes building science. Legislation to that effect passed in 2009 and began to phase in last fall. When asked what prompted the legislation, Jon Chandler, CEO of the Oregon Home Builders Association, says that during the legislative session in 2007, “builders got pummeled in the press over construction defects—mold claims, water-intrusion claims, and so on. There was a solid week of front-page, above-the-fold articles. That was the tipping point.”
Not everyone agrees that contractor licensing and continuing education are the answer. Back in the 1990s, Minnesota had a requirement similar to Oregon’s, and Huelman was one of the people who taught the building-science courses. “I started to lose a little faith,” Huelman says, “because the owner of the company, or some delegate, was going to the class and learning about building science or energy, but that wasn’t traveling down to the guy who was putting in the window or to the siding contractor who was messing up the housewrap.”
Mark LaLiberte, who helped to set up the training programs in both states, hesitates to recommend any solution that will burden builders with more regulation, but he does advocate continuing education, especially to address building-science issues. “It’s the only solution that will bring builders to the point where they say, ‘I’m going to do this because it’s my reputation, it’s my business, and I’m a professional.’” He wants builders to seek that education on their own.
One thing everybody agrees on is that building science, just like the devil, is in the details. That’s why Straube says, “If I had to pick anybody to give training to, it would always be the site supervisor first.” Here and there, in fits and starts, some builders are getting trained, at conferences and online, through green-building certification programs, through Energy Star and Building America, but no single program is comprehensive or sufficient. The quality of the education offered varies considerably, and hucksters have set up shop to exploit this critical need. Even the most conscientious builders have a hard time learning what they need to know about building science.How water gets into houses After rain and plumbing leaks, airborne moisture is the biggest source of water in walls and roofs, which is why sealing air leaks—creating an air barrier—is so important. The difference between (and relative importance of) air barriers and vapor retarders is probably the most widely misunderstood concept in high-performance home building.
Performance-based codes would help
“Code development isn’t predicated on good building science,” Huelman says. “It’s a political negotiation.” He explains that it often takes several years for a building failure to show itself. Then it takes several years to develop the language in the code that leads to a fix for the problem. It then takes several more years before the code is adopted, and another several years before the code officials are sufficiently trained. “You’re 10 to 15 years behind the eight ball,” Huelman says.
Given the complexity of the code-changing process, Totten worries about another risk. He points out, for example, that when you change code requirements for the airtightness of homes, you also have to change the codes for ventilation rates. “If we have a lag on one, particularly the ventilation rate, we’re going to create a whole pool of new problems.”
Perhaps the biggest issue with codes from the standpoint of building science is that they are prescriptive. They suggest that if you vent the crawlspace or if you install insulation with the correct R-value, you won’t have a moisture problem. However, success depends on how well you install the insulation and on how well you seal the air barrier, which is why Sweden, for example, has gone to performance-based energy codes. Like the Passive House standard, Sweden’s energy codes limit total energy use per square meter and specify an air-change rate. Meeting these requirements puts considerable pressure on builders to understand the science and to get the details right.
Whatever happens with our codes, our building inspectors need to understand building science thoroughly. They are the ones assessing the quality of the energy details before they’re covered up. Inspectors also have the authority to allow substitutions for code requirements, which can be dangerous without a deep understanding of building science. But it is no easier, and no more likely, for inspectors to educate themselves than it is for builders.
Let’s admit that it’s complicated
At some point in the past 30 years, without fanfare and without most of us ever acknowledging it, our houses crossed a threshold of complexity. They became dynamic systems whose construction and performance goes beyond the abilities and understanding of many of us in the industry. Most architects, builders, and code officials still can’t explain the difference between a vapor retarder and an air barrier. It’s not that we’re stupid. We know plenty of other things, but we haven’t had to know about building science. Now we do.
Creating homes that are comfortable, healthful, durable, and efficient means learning to build airtight, highly insulated houses. We can’t keep complaining that it’s too expensive. We can’t keep saying, “Houses need to breathe,” and then use that as an excuse to be careless about how we put them together. And we can’t be lazy and rely on prescriptive solutions. Those of us who build houses really need to understand the science of how they work. We have to take responsibility for educating ourselves.
ASHRAE and the American Chemistry Council (ACC) have signed a Memorandum of Understanding (MoU) formalizing the organizations’ relationship.
The MoU was signed by 2019-20 ASHRAE President Darryl K. Boyce, P.Eng. and ACC President & CEO Chris Jahn on November 19 in Atlanta. The agreement defines parameters on how the two organizations will collaborate more closely to continue promoting the advancements of a more sustainable built environment.
The organizations have committed to work together on the following shared objectives:
- Engaging in projects and activities whose purpose is to help improve the health, safety, and welfare of communities through the built environment.
- Supporting the development, adoption, and enforcement of building codes standards that support those improvement goals.
- Promoting the use of sound science in the development and assessment of building standards and codes.
- Enhancing building performance by fostering improvements in energy efficiency, resiliency, indoor air quality, and the health, well-being, and productivity of building occupants.
- Increasing communication between professionals of the building, design and construction industry and chemistry industry to promote innovation and sustainability.
“We are pleased to collaborate with ACC as we work toward our shared goal of achieving optimal building performance,” said Boyce. “ASHRAE and ACC are on the forefront of developing innovative technologies that are significantly impacting the building industry. This partnership signifies our commitment to broadening industry knowledge of energy efficient and sustainable building solutions to support the health and well-being of building occupants everywhere.”
“The products of chemistry, from foam insulation and silicone caulks and sealants to plastics pipes and next-generation refrigerants, provide a range of benefits that help enable energy-efficient, sustainable buildings,” Jahn said. “We look forward to collaborating with ASHRAE to advance solutions that help enhance sustainability, health and wellness in building performance.”
We’re seeing a material shift, literally. There’s a sweeping wave of synthetic, fabricated materials being used more frequently in construction, and this is a paradigm shift in construction. Leading the pack are changes in how we insulate.
Read on to learn more about the pros and cons of Rigid Foam Sheathing in high-performance building.Rigid Foam as an Insulation Strategy
Rigid foam sheathing is a form of insulation — continuous insulation, to be exact — that’s applied to the exterior of the building. Continuous rigid insulation is a construction solution that provides a thermally efficient building enclosure. Rigid insulation sheathing is made of a rigid plastic foam that is typically sold in 4×8- or 4×10-foot boards. The boards are available in several thicknesses and R-values; 1-inch and 2-inch thicknesses are common. Rigid insulation provides thermal protection and it can also serve as an air and moisture barrier.
There are three primary types of rigid insulation: expanded polystyrene (EPS), extruded polystyrene (XPS), and polyisocyanurate (polyiso). EPS and XPS are thermoplastics, which are non-cross-linked polymers so they are susceptible to deterioration in high temperatures (BSC 2007). Polyiso is a thermoset, which is made up of cross-linked polymers so it has a much higher melting temperature. While properties can vary among specific products, XPS and polyiso tend to be higher density, higher R-value, and lower permeance than EPS.
When rigid foam insulating sheathing is installed on the exterior walls of a home, the foam can serve as a drainage plane, taking the place of house wrap for time and cost savings. To serve as a drainage plane, the seams in the foam sheathing must be properly taped with sheathing and flashing tapes to provide continuity of the drainage plane at joints between panels. The tapes must be durable enough to prevent ingress of water at panel joints for the life of the system. Sheathing tapes and sometimes flashing tapes are also needed to integrate the top edge of diversion flashings (head flashings, flashings over penetrations, step flashings, kick-out flashings, etc.) with the drainage plane.Rigid Foam and Building Codes
Because of its thermal properties, rigid insulation is being called for by certain codes and programs. ENERGY STAR(TM) requires that rigid foam or insulated siding be installed over walls if they are metal framed (ENERGY STAR 2015). ENERGY STAR also requires that rigid foam sheathing or insulated siding or a combination of the two be installed to a thickness of ≥R-3 in Climate Zones 1 to 4 or ≥R-5 in Climate Zones 5 to 8 (ENERGY STAR 2015).
Continuous rigid insulation also provides an effective solution to thermal bridging. Thermal bridging occurs wherever assembly components with low R-values (such as wood or steel) span from the interior to the exterior of the building. In traditional building construction, while the wall cavities are filled with insulation, there is no insulation at the window frames, door frames, studs, top plates and bottom plates; together this framing comprises nearly one-fourth of the wall area. Rigid insulation can be attached to the exterior side of the framing to provide a continuous insulating layer that reduces thermal losses through thermal bridging.3 Benefits of Rigid Foam Sheathing
More effective insulation
With R-values ranging from 3.6 to 8.0, rigid foam sheathing has much better insulation per inch than other materials (i.e. plywood has an R-value of 1.25 and fiberglass batts have an R-value of 3.14). This is especially critical in preventing damage (such as mold and rot) to framing and walls in areas with extremely cold or damp climates. Since rigid foam is applied on the outside it also prevents thermal bridging. Thermal bridging happens when there is the loss of heat due to an interruption in the insulation by a material that is more conductive. This typically happens when interior insulation intersects things like stud frames or electrical boxes.
Better at controlling moisture When it comes to controlling moisture, rigid foam serves two functions. It protects the wood sheathing or framing from any rain or water that leaks in under the siding. And it warms the interior sheathing or framing enough to prevent moisture accumulation from the heated interior air in the winter.
Better at preventing air leaks
When sealed with proper techniques and a suitable adhesive, rigid foam is an excellent air barrier. The same principle mentioned above that prevents thermal bridging also applies to air transfer. Unlike house wrap, which works to prevent infiltration (air coming into the building) but is poor at stopping exfiltration (air moving out of the building), rigid foam is able to do both.
Must be installed properly to limit air leaks and act as a weather-resistive barrier
Rigid foam does not require specialized equipment to install it but you do need to follow strict seam-sealing procedures to meet code.
Less structural strength than plywood or OSB sheathing
If rigid foam sheathing is used on top of wood sheathing, this doesn’t matter. However, if you want to use rigid foam in place of wood sheathing it needs additional bracing to prevent racking.
Slightly more expensive
Adding a layer of rigid foam on top of plywood or OSB sheathing will increase the cost of the project. However, this is just a short-term, fixed cost. Rigid foam often pays for itself with lower utility bills over the long term. And it may put off or prevent costly work to repair rot in walls or framing.
When using foam insulation, you’ll need to decide whether you intend to use OSB in addition to the rigid foam to serve as the building sheathing or if the rigid foam layer will itself serve as the sheathing, and you’ll need to determine what will serve as the drainage plane and where this layer will be. These decisions are determined somewhat by climate.
- Extruded polystyrene (XPS) and foil-faced polyisocyanurate (polyiso) are high-density rigid-foam insulations that can be used as exterior insulation and are generally approved, per Building America(SM) to be used as a drainage plane if the joints are sealed.
- Insulation sheathing membranes rely on tape to complete the air barrier; the tapes should be applied on a clean, dry, warm surface.
- For the rigid insulation to be used as a water-resistive barrier, the vertical plane of the exterior face of the sheathing must be as smooth and continuous as possible.
The lowest cost, highest performing rainwater management strategy is rigid polymeric foam sheathing with sealed joints (Lstiburek 2006, 2010). There is an existing construction challenge of sealing the joints in rigid polymeric foam sheathing in a reliable and durable manner to prevent water ingress.Best Practices for Taping Rigid Foam Sheathing
The Building America Solution Center has the following builder guidelines for taping rigid foam:
- When rigid foam is used as the weather-resistive barrier and/or the air barrier, tape all seams using manufacturer-recommended tape per the manufacturer’s instructions. Wipe the surface of the foam with a clean dry cloth before taping to ensure good adhesion by removing dirt or oil residue which is common on foil-faced polyiso (Smegal and Lstiburek 2012).
- When rigid foam is used as the weather-resistive barrier, apply flashing shingle fashion around all openings for doors, windows, etc., to reduce bulk moisture intrusion and air infiltration.
- Center the tape over the joint to cover the fasteners. Fasteners located in the center areas of the boards do not need to be taped. Use a shingle fashion technique when taping joints. Avoid taping during extremes in temperature; install tape per the manufacturer’s instructions, which is generally between 15°F and 120°F.
- Apply pressure along the entire surface for a good bond. Remove all wrinkles and bubbles by smoothing the surface and, if necessary, repositioning.
When working with any new material, you have to make sure you have enough available surface contact. We’re seeing applications where tape works well with synthetics, but we’re also seeing materials that offer a very imperfect surface to bond to. As new materials are introduced, and airtightness remains a critical requirement, the industry needs a pressure sensitive tape that’s going to bond quickly to rigid insulation and stay that way.
Which is exactly why ECHOtape launched our new, next generation seaming tape. PE-M4535 is a proprietary high-performance building tape, made from an advanced polyester backing, which makes it extremely strong and easy to apply. Available in red, silver and white, it is a versatile product used in a wide variety of building envelope sealing applications, including cold weather applications. As excited as we are about PE-M4525, ECHOtape R&D team is continuing to develop additional seaming products to meet the needs of a rapidly changing building industry, products that will adhere to a wide range of building materials and surfaces including house wrap, exterior, and rigid insulation, sheathing, vapor barriers and a variety of underlayments.
Preventing and combating moisture damage to a structure is one of the oldest dilemmas in the building industry. Moisture intrusion can create problems both structural and aesthetic. As the industry has evolved, so have building codes and the materials utilized in helping reduce moisture intrusion.
WRBs—Purpose and Approved Materials
The International Building Code (IBC) requires the installation of a water resistive barrier (WRB) in all wall assemblies. WRBs are a type of specified material installed between the sheathing or studs and cladding, designed to help prevent water from reaching building components that could sustain extensive damage from moisture. Without a WRB, these components would be at greater risk of moisture damage.
There are several materials that have been identified as acceptable WRBs—asphalt felt, Grade D building paper, plastic house wraps, rigid foam insulation, liquid applied WRBs and certain types of sheathing panels. 1 Each has unique attributes, such as its level of vapor permeability, but only one is referenced in the building code—No. 15 asphalt felt.
The IBC specifies at least one layer of No. 15 asphalt felt that complies with ASTM D226 be applied to the sheathing or studs, but also states other “approved materials” can be utilized.2 In many instances, rigid foam insulation is one of the best choices due to its high moisture resistance and thermal performance, making it very suitable for energy-conscious builders and projects.3
Unlike batt, blown in or spray foam insulation, rigid foam insulations can be used to form a continuous insulation layer on the outside of the building. At the same time, this continuous insulation layer can protect the building from moisture. Of all the rigid foam options available on the market, polyisocyanurate (polyiso) has the highest R-value and has long been used as a WRB. Some continuous insulation solutions, such as mineral wool, cannot be used as approved WRBs.
How Polyiso can be Applied as a WRB
Polyiso insulation has been identified as an approved WRB in lieu of No. 15 asphalt felt, meeting the requirements of the IBC. With its high R-value and comprehensive range of thicknesses, compressive strengths and permeability options, polyiso is suitable as the WRB for many different commercial and residential applications.
In order for polyiso to be used as the WRB, it must be applied properly. Building code prescribes that alternative materials, regardless of their approval as a WRB, cannot interfere with the installation of other required materials.
Polyiso undergoes several different testing methods to ensure compliance. These include the AATCC water resistance test (conducted on polyiso material alone, as well as treated joints and the full assembly) and accelerated aging tests to gauge real-world exposure.3
With many WRB materials available, what exactly makes polyiso such a smart choice? Polyiso is able to fully cover wall studs, improving moisture control and reducing energy loss, and can be layered easily for enhanced R-value. In many cases, it also can come down to cost and labor efficiency. By being both a WRB and continuous insulation, it saves contractors a trip around the building. Additionally, polyiso provides the highest R-value per inch, allowing for thinner wall assemblies.
Once boards are installed per manufacturer’s instructions, the first and most important step in the installation process is selecting a durable and manufacturer approved joint treatment. The most common joint treatment is tape; however, others are available. Choosing proper tape can help prevent potential leaks that could lead to costly damage and repairs in the long run. It’s also important to gently clean the surface of the polyiso before application to remove any dirt or residue that can hinder proper adhesion of the tape.4
The tape should be applied to the seams in shingle fashion, working from the bottom of the assembly upward to help reduce moisture and air intrusion. To ensure correct lapping, tape horizontal seams first, then vertical. Tape should be wide enough to overlap outside corners and cover the fasteners by at least 1-inch in each direction. Once this process is complete and all joints are sealed, cladding can be installed.
Best Practices & Advantages
While the process for installing a polyiso WRB solution is fairly standard, there are some best practices that can help ensure the quality and longevity of the WRB. Moving the WRB outbound (or closer to the cladding) moves the drainage plane further from the interior, helping reduce the chance of moisture intrusion. For instance, in projects with a brick veneer, a layer of polyiso behind the veneer often is the best choice. 5 Installing the WRB closer to the cladding also helps with value engineering and labor savings, as less labor and materials are needed for the application. It also often improves building performance and reduces construction costs.
A polyiso WRB offers several other advantages as well. If desired, it often can function as a vapor barrier, helping reduce the diffusion of vapor through the wall assembly. Some polyiso products also have a dark facer for use in open joint rainscreen assemblies. The dark, non-reflective facer serves to black out the substrate.
Located in the North Hollywood area of Los Angeles, NoHo West is a new development featuring both residential and commercial space. This mixed-use development, formerly the site of a shopping center that sustained severe earthquake damage, has been constructed to adhere to California’s strict environmental building standards—one of which will take effect in 2020 requiring continuous insulation in all new constructions. The initial design called for continuous insulation, with the WRB membrane adhered to the face of the insulation. When budget and scheduling needs were evaluated, polyiso’s two-in-one function as insulation and weather barrier helped meet performance requirements and reduce cost.
To reduce labor costs and provide the wall assembly with better performance, the subcontractor made the decision to utilize polyiso as both the continuous insulation and WRB. A third-party conducted on-site testing as requested by the owner and validated that polyiso was an acceptable WRB for NoHo West. The high R-value of the polyiso coupled with fewer thermal breaks in the system will add to its energy efficiency and protect against moisture intrusion. As an added value, it also reduced the project’s material and labor costs and shortened the construction timeline.
As with any project, it’s important to evaluate the specific codes, standards and project needs before making a decision about the WRB material. In many cases, polyiso is a great choice that will serve as both the WRB and continuous insulation and provide additional environmental benefits.
The code development process for the 2021 editions of the International Building Code (IBC), International Residential Code (IRC), and International Energy Conservation Code (IECC) are coming to a close. While many proposals are still awaiting final building official on-line voting, two proposal that received broad support -- including a unanimous committee vote for approval -- have already been confirmed by consent vote of code officials. These two proposals represent long over-due advancements for the water vapor control provisions of the IBC and IRC and will provided needed coordination with insulation requirements in the IECC.
The two proposals can be accessed via code hearing agenda published at the International Code Council’s website. To access the specific proposals from the downloadable hearing agenda, use the following proposal numbers and hearing group:
- FS120-18 Group A (IBC Fire Safety Committee)
- RB223-19 Group B (IRC Residential Building Committee)
These proposals have been coordinated so that the IBC and IRC vapor retarder provisions would be similar in format and technical requirements. The significant formatting improvements include a tabulation of vapor retarder requirements by climate zone. Significant technical improvements include recognition of “smart” or “responsive” vapor retarders as a means to control water vapor movement in assemblies while also allowing water vapor to escape. Even more significant, vapor retarder and insulation ratio requirements for use with continuously insulated walls have been provided in tabulated form to facilitate moisture control (see Table 1 and Figures 1 and 2 below as an example of advanced solutions added to the 2021 codes). For additional information on appropriate and code-compliant use of continuous insulation and water vapor retarders, refer to www.continuousinsulation.org.
CONTINUOUS INSULATION WITH CLASS II VAPOR RETARDER
Continuous insulation with R-value ≥3 over 2x4 wall.
Continuous insulation with R-value ≥5 over 2x6 wall7
Continuous insulation with R-value ≥5 over 2x4 wall.
Continuous insulation with R-value ≥7.5 over 2x6 wall8
Continuous insulation with R-value ≥7.5 over 2x4 wall.
Continuous insulation with R-value ≥10 over 2x6 wall
TABLE NOTE: A Class II vapor retarder is typically a Kraft paper facer as commonly applied to fiberglass batt cavity insulation. Kraft paper is also a “smart” vapor retarder, thus maximizing inward drying potential when foam plastic continuous insulation is used on the exterior side of the wall. Also the minimum continuous insulation amounts shown in the table ensure the wall remains sufficiently warm and resistant to moisture accumulation or condensation during the winter. These requirements are for moisture control and must be coordinated with minimum insulation amounts required for energy code compliance. Using a greater amount of continuous insulation for a given level of cavity insulation will further improve moisture and energy performance. For the technical basis of this table and the above referenced code proposals refer to: ABTG Research Report No. 1701-01 and ABTG Research Report No. 1410-03
FIGURE 1. U.S. Climate Zone Map. Click to enlarge.
FIGURE 2. A typical “hybrid” wall using cavity and continuous insulation to achieve building code and energy code compliance. Click to enlarge.
ASHRAE has released an expanded, revised version of a well-known energy standard.
ANSI/ASHRAE/IES Standard 90.1-2019, Energy Efficiency Standard for Buildings Except Low-Rise Residential Buildings, contains more than 100 changes from the 2016 version, including numerous energy-saving measures.
“The goal of the 2019 version of 90.1 was to provide clearer guidance for exceeding efficiency goals,” said Drake Erbe, chair of the Standard 90.1 committee. “This new version focuses on energy-saving measures which we hope will reward designs for achieving energy cost levels above the standard minimum and result in more efficient buildings and more innovative solutions.”
Some significant changes include:
Administration and Enforcement: Commissioning requirements were added to the standard for the first time. Section 4.2.5, “Verification, Testing, and Commissioning,” was greatly expanded and requirements were outlined for commissioning in accordance with ASHRAE/IES Standard 202.
Building Envelope: For vertical fenestration, the categories of “nonmetal framed” and “metal framed” products were combined. Minimum criteria for SHGC and U-factor were upgraded across all climate zones. The air leakage section was revised to clarify compliance. Changes to the vestibule section refined the exceptions and added a new option and associated criteria for using air curtains.
Energy Cost Budget Method: Numerous changes were made to ensure continuity. The baseline was set for on-site electricity generation systems.
Performance Rating Method: Appendix G rules and the corresponding baseline efficiency requirement were clarified. Explicit heating and cooling COPs were provided without fan for the baseline packaged cooling equipment. Rules were added for modeling the impact of automatic receptacle controls. More specific baseline rules were set for infiltration modeling. Clarification was added for how plant and coil sizing should be performed. Building performance factors in Section 4 were updated.
Both Compliance Paths: Clearer and more specific rules were added related to how renewables are treated. Extensive updates were added to the rules for lighting modeling.
Also new to the standard is use of the new fan energy index (FEI) as the metric for efficiency provisions for commercial and industrial fans and blowers.
Standard 90.1 has been a benchmark for the commercial building energy codes in the United States and a key basis for codes and standards around the world. The 2019 version is the 11th edition published since the original standard was first published in 1975 during the U.S. energy crisis.
The Florida Building Commission considers updates to the statewide building code every three years. The state is currently moving forward with the most recent triennial update by opening up a public comment period on the draft 7th Edition (2020) update to the code. Comments to the draft will be accepted through January 2, 2020 or at rural development workshops on February 4, 2020 or April 7, 2020. Please send comments to following email address: email@example.com. The Florida Building Code 7th Edition (2020) will go into effect on January 1, 2021.