Energy Efficiency and Building Science News

Improving Envelope Performance in Existing Properties

Wed, 2019-05-22 13:58
Building ScienceEnergy Efficiency

If a property owner is considering an upgrade to improve energy efficiency, a building envelope inspection is recommended first.

Designing a building with an efficient envelope from the start is the optimal solution, but the business case is often favorable for upgrades in existing properties. However, before proceeding with any building upgrade, the recommended first step is identifying deficiencies in the existing envelope.

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Why Polyurethane Foam is an Excellent Roofing Material

Wed, 2019-05-15 16:02
Building ScienceEnergy Efficiency

Society’s movement towards sustainability has impacted the roofing industry significantly. The intent of the sustainability movement is to encourage use and development of environmentally-friendly options. In the roofing area, this is achieved by installation of products providing long-term service with renewability options and cost-effective service. As regulation increases, manufacturers are moving more towards “green” focused products. These products are durable, environmentally friendly and cost-effective.

Polyurethane Foam

For flat roofs, spray polyurethane foam is an excellent option to consider. It consists of two components (resin and polyisocyanurate) joined together with heat and pressure, which react to rise and form a solid surface. Foam has a number of distinct advantages. It is an insulating material, serves as soundproofing, adds rigidity to a structure, is lightweight and very durable. Foam has been used in roofing applications since the 1960s.

Since it is a seamless product, maintenance is fairly simple. A utility knife and a tube of caulk will serve to address most issues that might arise with a foam roof.

Polyurethane foam has one distinct disadvantage—it will break down over time when exposed to the sun. This is overcome by coating the roof with an elastomeric acrylic, silicone or polyurea, all of which block ultraviolet rays from getting at the foam. The coatings can be used to add a variety of colors to the roof system, although the lighter colors tend to add the most to the insulating value of the roof system.

Polyurethane foam can be installed to any thickness in a series of passes called “lifts.” This puts insulation on the outside of the building, blocking heat or cold from passing through to the structure beneath, and vice-versa. No other roofing material has the combination of strength, formability, seamlessness and insulating value provided by spray polyurethane foam.

As society becomes more environmentally-conscious, architects and developers are converting to more “green” products for construction purposes. For more information about “green” roofing materials, be sure to reach out to your local roofing expert.


Plant-Based Thermal Material to Rival Styrofoam?

Wed, 2019-05-15 15:38
Building ScienceEnergy Efficiency

Washington State University researchers have developed an environmentally-friendly, plant-based material that for the first time works better than Styrofoam for insulation.

An environmentally-friendly, plant-based material that for the first time works better than Styrofoam for insulation. (Photo : WSU)

The foam is mostly made from nanocrystals of cellulose, the most abundant plant material on earth. The researchers also developed an environmentally friendly and simple manufacturing process to make the foam, using water as a solvent instead of other harmful solvents.

The work, led by Amir Ameli, assistant professor in the School of Mechanical and Materials Engineering, and Xiao Zhang, associate professor in the Gene and Linda School of Chemical Engineering and Bioengineering, is published in the journal Carbohydrate Polymers.

Researchers have been working to develop an environmentally friendly replacement for polystyrene foam, or Styrofoam. The popular material, made from petroleum, is used in everything from coffee cups to materials for building and construction, transportation, and packaging industries. But, it is made from toxic ingredients, depends on petroleum, doesn't degrade naturally, and creates pollution when it burns.

While other researchers have created other cellulose-based foams, the plant-based versions haven't performed as well as Styrofoam. They are not as strong, don't insulate as well, and degraded at higher temperatures and in humidity. To make cellulose nanocrystals, researchers use acid hydrolysis, in which acid is used to cleave chemical bonds.

In their work, the WSU team created a material that is made of about 75 percent cellulose nanocrystals from wood pulp. They added polyvinyl alcohol, another polymer that bonds with the nanocellulose crystals and makes the resultant foams more elastic. The material that they created contains a uniform cellular structure that means it is a good insulator. For the first time, the researchers report, the plant-based material surpassed the insulation capabilities of Styrofoam. It is also very lightweight and can support up to 200 times its weight without changing shape. It degrades well, and burning it doesn't produce polluting ash.

"We have used an easy method to make high-performance, composite foams based on nanocrystalline cellulose with an excellent combination of thermal insulation capability and mechanical properties," Ameli said. "Our results demonstrate the potential of renewable materials, such as nanocellulose, for high-performance thermal insulation materials that can contribute to energy savings, less usage of petroleum-based materials, and reduction of adverse environmental impacts."

"This is a fundamental demonstration of the potential of nanocrystalline cellulose as an important industrial material," Zhang said. "This promising material has many desirable properties, and to be able to transfer these properties to a bulk scale for the first time through this engineered approach is very exciting."

The researchers are now developing formulations for stronger and more durable materials for practical applications. They are interested in incorporating low-cost feedstocks to make a commercially viable product and considering how to move from laboratory to a real-world manufacturing scale.


Video: Better Wall Insulation with ‘Advanced Framing’

Wed, 2019-05-15 15:31
Building ScienceEnergy EfficiencyAdvanced Framing and Advantech Subfloor

Did you know that 3/4" Advantech subfloor panel isn't supported once framing members are further apart than 19.8"? 


2018 IgCC Vast Improvement for Energy Efficiency

Wed, 2019-05-15 15:19
Building ScienceEnergy Efficiency

It has been nearly half a decade since the American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE), the American Institute of Architects (AIA), the International Code Council (ICC); the Illuminating Engineering Society (IES); and the U.S. Green Building Council (USGBC) signed a Moratorium of Understanding to better align green building goals through ANSI/ASHRAE/ICC/USGBC/IES Standard 189.1, the International Green Construction Code (IgCC), and the LEED certification system.

For years, these groups had been working on their owner green building standards and frameworks. That started to change in 2009, when USGBC, ASHRAE, and IES teamed up to released Standard 189.1: Standard for the Design of High-Performance Green Buildings, Except Low-Rise Residential Buildings. It marked a momentous step forward, as the standard established minimum requirements for the siting, design, construction, and plans for operation of high-performance green buildings. Though loosely modeled around the categorical framework of LEED, Standard 189.1 provided the industry with a true model standard for green building rather than to some sort of guideline or volunteer rating system. Though many municipalities across the U.S. have local ordinances requiring LEED, Standard 189.1 offered a document more conducive to amendment and adoption as code for a wider range of jurisdictions.

However, by 2012 the ICC released its first edition of the IgCC, which was similar in breadth and scope to Standard 189.1, but harmonized with the organization's widely utilized international model codes (i.e., the "I-Codes"). Recognizing the duality in the marketplace, and to help circumvent potential regulatory complications, the 2012 (and the subsequent 2015) version of the IgCC included Standard 189.1 as a project compliance option.

A bit confusing, yes; and the duality (and seeming competition) of Standard 189.1 and IgCC was compounded by pre-existing LEED mandates in various cities. This was the impetus for the August 2014 Memorandum of Understanding. As a result in 2015, ICC was added as an additional cosponsor of the 2017 edition of Standard 198.1, which served as the technical content of the 2018 IgCC.

At last, we're seeing the fruits of the ICC/ASHRAE/USGBC strategic alignment

At a moment when LEED is pivoting toward an increasingly more stringent certification model based on an integration of strategies and measured performance (utilizing the emerging arc platform), the 2018 IgCC is poised to fill the necessary role of setting a minimum standard for energy and environmental design.

This is why the IgCC is important. In the spirit of the acronym, LEED will continue to lead. For cities and institutions struggling with LEED mandates, the 2018 IgCC may be considered. For a jurisdiction looking for a model standard from which to codify green building, The 2018 IgCC may be more appropriate than a volunteer rating system.

The 2018 IgCC is the first fully integrated edition of the IgCC to be developed cooperatively by ICC and ASHRAE. It retains the general LEED-like structure of Standard 189.1 That is intentional. USGBC’s fingerprints are all over Standard 189.1 and subsequently the IgCC. This is part of a broader effort toward transforming the building design and construction industry.

As traditional codes evolve to include sustainability measures, green building codes such as IgCC will compliment and expand on the traditional codes to set holistic and rigorous minimum standards for green building with clear and specific requirements including provisions that provide safe and substantial construction in a manner that is harmonized with LEED. As this aggregate of codes set minimum standards, LEED as a volunteer third-party certification systems will provide a pathway to help projects exceed the minimum requirements and provide opportunities for leadership through high-performance design and construction. This past November at Greeenbuild, two months after the release of the 2018 IgCC, USGBC raised the bar beyond Platinum certification by launching LEED Zero, a complement to LEED that verifies the achievement of net zero goals through measured data regarding carbon emission, (source) energy, (potable) water, and waste (via TRUE Zero Waste certification).

Market transformation will require an increasingly positive environmental impact by our building projects. Traditional building codes and model green building codes must continue to advance and integrate over time as LEED and other rating systems ratchet up in stringency and become more sophisticated. Illustration courtesy of USGBC. Click to enlarge.

Let's be clear: 2018 IgCC is not LEED-Lite

As the advancements of LEED shift it toward ongoing measured performance, the 2018 IgCC signals the future manifestation of what our industry has always understood as a prescriptive "credit-driven" process to realize a green building project. But from this point forward, such a system will persist as an evolving model building code with normative language that lends itself to enforcement. The 2018 IgCC is not a watered-down concession to LEED. The 2018 IgCC is quite stringent in many regards. If adopted without amendment,  it would codify:

  • Rainwater management provisions requiring infiltration, evapotranspiration, rainwater harvesting, collection and use.
  • Water consumption measurement devices with remote capability.
  • Envelope and mechanical requirements beyond the minimums set forth by ASHRAE Standard 90.1-2016.
  • Mandatory provisions governing acoustical control for the building envelope, interior spaces and the design of the mechanical systems.
  • A total construction waste threshold of 42 cubic yards or 12,000 pounds, per 10,000 square-feet of floor area for new building projects.
  • Specific requirements for building functional performance testing, a building project commissioning process, and measurement and verification.
  • A limited degree of provisions with regard to building project programming, equipment purchasing, facility operation and maintenance policy, and staff training requirements.

The message from the green building design and construction community is clear: we are united and the future of green building will rest on robust, comprehensive standards that will require project teams and owners alike to take a more vested role in the design, construction, operations, and maintenance of our built environment.


Analyzing the Significant Impacts of Water Infiltration

Wed, 2019-05-15 15:04
Building ScienceEnergy Efficiency

The ways in which liquid and vapor move through our building envelopes are complex, and even today not completely understood; but the fact that lots of water can (and does) move through porous building materials is a phenomenon that rules over so much of the way we build.

Click to enlarge.

Two major modes of moisture travel—gravity and capillary action—are related to bulk water management, which is essential to the longevity of any building envelope assembly consisting of porous materials.

Two other major modes address how water vapor can work its way through a building envelope assembly. Managing vapor drive is a critical damage function of a building envelope assembly. Building science professionals, designers, and engineers have long debased solutions for managing how vapor may diffuse through an assembly and pose a condensation risk. The bottom line with regard to diffusion is to understand seasonal vapor drive and afford an assembly the opportunity dry. Trapping moisture in an assembly may lead to major problems.

Air infiltration poses a greater condensation risk than diffusion—and it's not even close. 

Figure: Quantity of water transmitted through a sheet of gypsum board during a heating season in a cold climate via vapor diffusion and air leakage through a 1-square-inch hole. This figure is adapted from an illustration created by Building Science Corporation. Click to enlarge.

Project teams will pore over issues related to permeance, condensation risks, and strategic placements of vapor retarders in hopes of managing vapor-related moisture issues. However, controlling the flow of air infiltration is far more important than controlling vapor diffusion.

According to a classic analysis by Building Science Corporation, as offered in their Builder's Guide for Cold Climates, during a the heating season in a cold climate region, vapor diffusion through a solid a 4-foot by 8-foot sheet of gypsum board may result in about 0.3 L (1/3 quart) of water being transmitted to the interior. By comparison, the air leakage through a 1-square-inch hole in the middle of the gypsum board over the same period of time may result in approximately 28.4 L (30 quarts) of water being transmitted to the interior—90 times more water than through diffusion.

Infiltration can account for over half of the annual heat exchange through a poorly sealed building envelope; and with that air potentially comes a great amount of vapor. A leaky envelope can undermine even the most optimized vapor diffusion strategy. This underscore the critical need for tight building envelopes as standard practice.


ASTM Seeks Thermal Insulation Resiliency Research

Wed, 2019-05-15 14:43
Building ScienceEnergy Efficiency

Dates: Wednesday October 28 2020 - Thursday October 29 2020

Location: Renaissance Orlando at SeaWorld Orlando, FL

Sponsored by: C16 Thermal Insulation

Deadline for Abstract Submittal: Friday June 07 2019

About the Event

Papers are invited for a Symposium on Performance, Properties and Resiliency of Thermal Insulations to be held Wednesday and Thursday, October 28 & 29, 2020. Sponsored by ASTM Committees C16 on Thermal Insulation and E06 on Performance of Buildings, this symposium will be held at the Renaissance Orlando at SeaWorld in Orlando, FL, in conjunction with the October standards development meetings of the committee.

The objective of this symposium is to present and discuss current research on physical and chemical properties of thermal insulation materials and assemblies, with special attention to resiliency and durability.

Possible topics include:

  1. Resiliency and Durability of Thermal Insulations
    • Building Applications
    • Industrial Applications
    • Extreme Conditions and Events
  2. Physical Property Data and Test Methods for Conventional and Advanced Insulations
    • Hybrid Systems (PCM related, Cellular plastics, Aerogels and nano-scale material, Reflective materials)
    • Vacuum insulations
    • Pipe Insulation (above ambient temperature)
  3. Appliances, Transport, and Shipping
    • Refrigeration (residential, commercial, and industrial)
    • Transportation
    • Packaging
  4. Low-Temperature Applications Requiring Moisture Control
    • Refrigeration
    • Cryogenic
    • Chilled Water
    • Special applications
  5. In-situ Performance
    • Case studies-energy savings
    • In-situ measurement techniques

The language of the symposium will be English.

Abstract Submittal

To participate in the symposium, authors must submit a 300-word preliminary abstract using the online Abstract Submittal Form no later than June 7, 2019. To ensure your abstract was received into the ASTM database, please email to inform us that you have submitted an abstract.

The abstract must include a clear definition of the objective and approach of the work discussed, pointing out material that is new, and present sufficient details regarding results. The presentation and manuscript must not be of a commercial nature nor can it have been previously published. Because a limited number of abstracts will be accepted, be sure that the abstract is complete to allow for careful assessment of the paper's suitability for this symposium. Symposium Chairman Diana Fisler and Co-chair Marcin Pazera will notify you via email and postal mail by July 5, 2019 of your paper’s acceptability for presentation at the symposium. If the preliminary abstract is accepted, the presenter/author will be requested to submit a final, camera-ready, abstract several months before the symposium. The final abstracts will be distributed in an abstract booklet at the symposium.


Symposium presenters are required to submit their papers to the Selected Technical Papers (STP), an online and printed, peer-reviewed publication for the international scientific and engineering community. After the final selection of abstracts has been approved, the ASTM Editorial Office will send authors’ instructions via email only. Manuscripts to be peer reviewed for the STP are due online no later than January 17, 2020 at the ASTM Editorial Office. The corresponding author (the author who is the main contact with ASTM Headquarters) will receive a copy of their paper in portable document format (.pdf). All published authors will have the opportunity to purchase reprints of their papers at a nominal cost. Only those papers submitted by the manuscript due date will be included in the STP.

Please note that all submitted papers are subject to single blind peer review and will be submitted to the Library of Congress with an ISBN number and will be reviewed for inclusion in the "Thomson & Reuters Web of Science's Conference Proceedings Citation Index" (CPCI) and Google Scholar.

Technical Chair Contact Information

Additional information about the symposium is available from Symposium Chairman Diana Fisler via email at, or by phone at +1 303-378-9141; or Symposium Co-chair Marcin Pazera via email at or by phone at +1 740-777-7256.


DOE Updates Building Energy Modeling Tools

Wed, 2019-05-15 14:38
Energy Efficiency

This OpenStudio energy model was used to evaluate the conversion of a 1950s Army barracks to a zero net energy (ZNE) office building as part of the Fort Carson (CO) Energy Research Project.

Whole-Building Energy Modeling (BEM) is a versatile, multipurpose tool that is used in new building and retrofit design, code compliance, green certification, qualification for tax credits and utility incentives, and real-time building control. BEM is also used in large-scale analyses to develop building energy-efficiency codes and inform policy decisions. So what exactly is BEM? And what roles does the U.S. Department of Energy (DOE) play in the BEM industry and community? Learn more about BEM, its uses, and BTO’s BEM portfolio.


DOE Issues Preliminary Determination of Energy Savings for Residential Buildings

Wed, 2019-05-15 14:20
Energy Efficiency

The Department of Energy (DOE) has published its affirmative determination that the 2018 International Energy Conservation Code (IECC) will increase energy efficiency in residential buildings. According to the DOE analysis, "buildings meeting the 2018 IECC (as compared to the previous 2015 edition) would result in national energy savings of approximately:

  • 1.97 percent energy cost
  • 1.91 percent source energy
  • 1.68 percent site energy"

Comments can be submitted within 30 days from publication of this Notice in the Federal Register.

ASHRAE has recently published its own standard for residential buildings that presents a new approach to delivered residential building energy performance and seeks to deliver residential building energy performance that is at least 50 percent more efficient than the energy efficiency defined by the 2006 IECC. To learn more about ASHRAE Standard 90.2 – Energy Efficient Design of Low-rise Residential Buildings, click here.


State Legislature Building Code Updates

Wed, 2019-05-15 14:16
Building CodesEnergy EfficiencyColorado

Colorado HB 1260 passed the Senate and would require local building codes to include the most recent three editions of the IECC.


Nebraska legislators have sent a bill to Governor Pete Ricketts that would update the state's energy codes for residential and commercial buildings for the first time in a decade. The bill, LB 405, updates the state energy codes from the 2009 edition to the 2018 edition of the International Energy Conservation Codes and requires counties and cities within the state to notify the State Energy Office upon amending or modifying local building or construction codes.


SEDAC Offering Illinois Energy Conservation Code Webinar

Wed, 2019-05-08 16:47
Building CodesEnergy Efficiency

The Smart Energy Design Assistance Center (SEDAC) at the University of Illinois at Urbana-Champaign, on behalf of the Illinois EPA Office of Energy, is offering an Illinois Energy Conservation Code training opportunity for community code officials, and construction and design professionals. The upcoming webinar on 2018 IECC for Existing Buildings will be held on May 22, 2019 at 12 p.m. CT. As part of its advocacy in Illinois, PIMA previously recommended that the state host trainings on the energy code requirements for existing buildings. 

Register for Webinar


Illustrations: Housewrap and Drip Edging Done Right

Wed, 2019-05-08 16:34
Building ScienceEnergy Efficiency

A few years ago, my company was called to look at a modest, pre-fab ranch-style house with a water-intrusion problem. The homeowner suspected a roof leak. Inside the house, water was staining ceilings and walls and running down windows, and there was a smell of mildew. A few years earlier, another contractor had reshingled the roof (over existing shingles), installed replacement windows, and re-sided the house exterior with vinyl siding.

The drip edge was installed tight to the fascia.

It was directing water behind the gutters, causing saturation and major damage in the house walls.

What we found when we inspected the roof was not a roof leak. Instead, the trouble had begun with the installation of the drip edge and gutters. One simple oversight started the entire problem: The drip edge was applied too tight to the fascia trim. I couldn’t even fit a fingernail between the drip edge and the fascia board. That meant that the water would run straight down off the roof, wrap around the drip edge and onto the coil-wrapped fascia, and run down behind the gutter instead of falling into the gutter where it was supposed to go.

But that was just the beginning of the trouble. There was no roof overhang on this house. And when the water reached the bottom of the fascia, which was applied tight to the house walls, it would seep back to the sheathing.

There was no flashing installed that could direct the water back out away from the house or down onto the housewrap, which had been cut so it butted up against the bottom edge of the one-by fascia rather than running up behind it. Once the water reached the crucial seam where fascia met sheathing, it dripped down behind the housewrap.

Water soaked the sheathing. Over the years, the water rotted the sheathing in multiple places. When we removed the sheathing, we found rot around all the windows below the eaves, and some even on the gable-end windows. Housewrap on the walls stopped short of the windows, and wasn’t integrated into any kind of tape or flashing. The window trim was installed in a way that let water penetrate to the sheathing and the window openings.

To fix the problem, the author first had to strip away and replace the siding and sheathing.

Water had soaked the insulation at the bottom of the wall, creating a habitat for ants and the insects that feed on them. In many places, even the framing was saturated and rotted, blackened by rot to the point that it looked as if it had been burned.

In an ideal world, of course, this house would have had a roof overhang, and that would have helped. It would also have been a really good idea, when first trimming the fascia along the eaves, to have made an additional one-inch bend in the bottom edge of the wrap so that it returned to lie flat against the sheathing (a common trim treatment that we’ve all seen plenty of times). But even without those obvious touches, this house would have been OK if the roof-to-wall connection had been well flashed, the walls had been properly wrapped, and the windows had been properly flashed and sealed.

Click to enlarge.

In this case, our scope of work didn’t include reroofing or replacing the drip edge. We did go around the house and pull and bend the lower edge of the drip edge away from the fascia as much as the material would allow, to facilitate dripping into the gutter instead of behind it.

But our main project was to remove all the siding and sheathing, repair rot (including reframing windows), replace the bug- and mold-infested insulation, resheathe the building, construct a working drainage plane, and flash all the windows correctly into the housewrap.

To manage water that might still make its way from the roof edge back to the house wall, we added a piece of metal flashing extending behind the fascia to direct water out onto the housewrap if it managed to make its way back to the wall. We extended the housewrap up at the top of the wall, high enough that it fell behind this piece of flashing.

Now the house is tight and dry. But had the roofers initially left a half inch of space between the bottom flange of the drip edge and the fascia, the homeowner might have been spared this ordeal and a significant expense.

Of course, the drip-edge detail is not the only factor in the damage here. The previous contractor did many things wrong, and if you look at the number of circumstances that had to align in order to create this much damage, the lack of a roof overhang is certainly one of them. If the house had an overhang, things probably would not have gotten this bad. The fascia itself could have been damaged, if it were a wood fascia, but the water couldn’t have traveled back to the house as easily, and the major damage to the wall below would most likely have been avoided.


Insulation Can Control Basement Floor Moisture

Wed, 2019-05-08 16:22
Building ScienceEnergy Efficiency

QMy clients want to use as living space the new walkout basement of an addition I'm building for them, but they're concerned about potential moisture-related problems with the planned carpet flooring. I've proposed installing a layer of rigid EPS foam followed by a screwed-down plywood underlayment on top of the basement slab, but I'm also considering a product called Dricore, a subfloor system consisting of engineered wood panels that have a molded polyethylene membrane on the underside. Which approach would be better at controlling condensation on the cool slab floor?

APaul Fisette, director of Building Materials and Wood Technology at the University of Massachusetts Amherst and a JLC contributing editor, responds: In any basement, your primary design objective should be to control surface water, so designing a good drainage envelope on the outside of the foundation that incorporates subslab drainage should be a priority.

According to code and good building practice, you will also need to insulate (either on the outside or inside) the basement walls. Then you can direct your attention to the floor.

The plastic cleats on the bottom of Dricore panels are designed to lift the engineered subflooring off a cool basement slab floor and create an insulating airspace.

While I have no personal experience with Dricore (see photos, left; 866-767-6374, ), it seems like an effective approach, provided that the basement has a good moisture-control system in place and the installed cost works for the project budget. Rigid foam with a plywood flooring underlayment might supply better insulation and be cheaper to install than the Dricore panels, but you'd lose a little bit of headroom.

However, if the house you're working on is still in the planning phase, the best approach is to insulate underneath the slab: First, install a 6-inch layer of crushed stone in the bottom of the excavation, then cover it with a sheet of 6-mil polyethylene and at least 1-inch-thick rigid-foam insulation. The concrete slab is then poured directly on top of the foam/poly layer.

This arrangement will keep your slab on the warm (conditioned) side of the envelope, making condensation less likely to develop on the slab. The carpet pad and carpeting can then be installed directly on the concrete slab, without the additional expense of an interior foam/sleeper/underlayment system.


ICC Takes a Look at Net-Zero in the Context of Today’s Codes

Wed, 2019-05-08 16:17
Building ScienceEnergy Efficiency

In building energy efficiency circles, the terms net zero, zero net energy, carbon neutrality and net carbon neutral are becoming increasingly common when discussing policy trends. However, there is confusion of what these terms mean and how they intersect with today’s energy codes.

This article is in response to a recent inquiry from a member seeking clarifying information on the International Energy Conservation Code (IECC) and “zero codes.” It is the first in a series addressing the changing landscape of building design, and the challenges, solutions and benefits of these changes.

The growing trend

The concept of net zero energy or net zero carbon buildings was first popularized by Architecture 2030 when they issued the 2030 Challenge to the building industry in 2006.  The challenge called for the reduction in the use of fossil fuels in new construction and major renovations resulting in carbon neutrality by 2030. Since that time, numerous programs, standards and codes have been developed to help move building practices closer to net zero, including the U.S. Department of Energy’s (DOE)  Zero Energy Ready Home, Architecture 2030’s Zero Code, the California Building Energy Efficiency Standards, and city- or state-specific energy codes such as the city of Boulder’s Energy Conservation Code or the state of Massachusetts Stretch code.

To underscore the magnitude of interest in energy and carbon reduction, in 2017 a total of 350 mayors had joined the Climate Mayors Agreement. Under this agreement, cities agreed to implement strategies that aligned with the greenhouse gas emission reductions outlined in the Paris Agreement. The signatories include the 10 largest cities in America — New York, Los Angeles, Chicago, Houston, Philadelphia, Phoenix, San Antonio, San Diego, Dallas and San Jose — along with hundreds of additional cities large and small in both red and blue states. The group of mayors, who represent more than 65.8 million Americans in 44 states, outlined a plan to align with the other 194 nations that signed on to the Paris Agreement.

At its 86th Annual Meeting, The United States Conference of Mayors passed resolutions supporting the achievement of 100% Renewable Energy in American Cities, and Uniting Cities to Accelerate Focus on the Economic and Climate Benefits of Boosting America’s Building Energy Efficiency. Within this latter resolution, they urged mayors from around the nation to work in conjunction with non-governmental organizations and other broad-based organizations promoting greater building efficiency to unite and maximize local government support for putting America’s model building energy code, the IECC, on a glide path of steady progress toward net zero building construction by 2050.


So, what is a net zero energy building? Generally, it means the energy use of the building is offset by renewable energy generated on-site. The DOE convened a broad group of stakeholders to develop a definition for a zero energy building and recognized that several terms can be used as synonyms. The DOE definition for a zero energy building is:

Zero Energy Building: An energy-efficient building where, on a source energy basis, the actual annual delivered energy is less than or equal to the on-site renewable exported energy.

In other words, the on-site renewable energy that is exported to the grid is greater than the off-site power generated and delivered to the building. It is important to note that not all entities agree that renewable energy must be generated on-site, and some jurisdictions are seeking carbon reduction and neutrality by providing renewable energy via the grid.

How far are current codes from net zero?

The distance of the 2018 IECC from net zero is nuanced on several factors, including the definition of net zero, building type and occupancy, climate zone, and acceptable level of cost-effectiveness. While in theory many of today’s buildings could be a zero energy building with the installation of on-site renewables such as photovoltaic panels or wind generation; high-rise buildings with limited roof area are constrained and many buildings have not yet achieved a level of energy efficiency that allows for cost-effective deployment of renewable energy, nor could many grid systems handle the level of on-site power generation required.

There is not one definitive answer on how much more efficient buildings should be before it is cost effective to make them net zero or zero energy building. However, we can look to the research of leading organizations to understand how far the codes have come, and the efficiencies that are still needed. According to analysis conducted by the DOE, overall buildings constructed to prescriptive provisions of the 2018 IECC use an average of 33 percent less energy than those constructed to the 2006 IECC.

Research from the Florida Solar Energy Center indicates that single-family, low-rise residential can be cost effectively net zero with an Energy Rating Index (ERI) score in the mid-40s. This compares to current code minimum scores of 57 to 62. If we consider an ERI of 100 aligning with the base efficiency of the 2006 IECC, an ERI of 45 is 55 percent better than the 2006 IECC.  This will vary by due to climate and local market conditions, but the research indicates when homes are 50 to 60 percent more efficient than the 2006 IECC it will be cost effective for on-site renewable power generation to offset the power use.

Commercial buildings have far greater variance — consider the energy use of a warehouse in temperate climate compared to a hospital with large cooling needs in a hot climate. Architecture 2030 research indicates that a 70 to 80 percent reduction in energy use from the 2006 IECC is needed to cost effectively designate a commercial building net zero or zero energy building. Again, this will vary by climate and occupancy. Applying the DOE definition of net zero — it is far more likely that the warehouse with expansive roof area in a temperate climate will net zero than a high rise hospital in a hot climate. In fact, the DOE recognized this challenge by offering parallel definitions for zero energy campuses, communities and portfolios.

Glide path to net zero by 2050

Returning to the Mayor’s Resolution, and addressing the “Glide path by 2050,” the analysis shows buildings generally need to be 50 to 80 percent more efficient than the 2006 IECC, depending on occupancy and climate zone, to potentially be considered net zero. Given that the 2018 IECC is, depending on occupancy and climate zone, 33 percent more efficient that the 2006 IECC,  cost-effective net zero construction would require a further reduction of approximately 20 to 50 percent. An average 2 to 4.5 percent decrease in energy use over each of the 11 code cycles from the 2018 IECC to the 2051 IECC would accomplish the mayor’s resolution of net zero by 2050.

As a point of reference, the 2009 and 2012 IECC provided a 10 percent and 33 percent reduction in energy use from the 2006 edition (respectively). Each of these codes included provisions that resulted in key improvements in efficiencies — involving key changes in design, construction and enforcement practices.  The 2015, and it is expected analysis will show the same for the 2018 IECC, did not impact energy efficiency by more than 1 percent.

More questions

Critical questions asked by designers, builders and code enforcement personnel include queries into effective design protocols, cost-effectiveness and feasibility related to both new construction and existing buildings.

Future articles will explore building practices and trends across the country. The DOE and the Institute for Market Transformation have conducted data collection and compliance studies on construction practices related to codes, and we will be able to look at national and regional trends. What code provisions have successfully reached market transformation, and which are still challenges.

Not unlike the current energy code, advanced efficiencies look at the increased insulation; reduced lighting power; proper sizing of heating, ventilation and air conditioning (HVAC) equipment; and eliminating unneeded use of energy through reduced air leakage, natural light and daylighting controls, occupancy controls, and HVAC controls. Advanced codes and design protocols also focus on building orientation and more complete system integration and commissioning. We will highlight both challenges faced by builders, and those builders that have found cost-effective means of building to current 2018 IECC levels and well beyond.

In addition, future articles will explore codes and policies that have been implemented to impact energy use of existing buildings. Finally, we will address how practices that reduce energy use in a building contribute to the health and safety of the building and its occupants, durability and resilience.


A Look Back at Insulation Products of the 20th Century

Wed, 2019-05-08 15:23
Building ScienceEnergy Efficiency

Insulation is critical to the energy efficiency of a building envelope. The U.S. Green Building Council’s LEED v4 building certification program, for example, awards up to two points to energy conservation from insulation that minimizes heat transfer and thermal bridging. However, insulation as we know it today is a relatively recent technology. While civilizations as early as the Ancient Greeks reportedly utilized asbestos, it was not until the 20th century that major advancements were made in insulative materials.

Courtesy BTHL. Click to enlarge.

In the 1900s, the design and construction of buildings with a thermal envelope to improve human comfort, as well as to reduce energy costs, spurred the production of insulating materials. The use of cavity wall construction for housing across the country led to the development of materials from mineral sources that could be installed as loose fill, blankets, or sheathing panels. The use of natural fibers extracted from wood and sugar cane produced a number of different insulating sheathing boards. By midcentury, new industrial processes resulted in lightweight glass fibers and mineral aggregates that combined thermal resistance with fire- and rot-resistance. Later still, the combination of insulating materials with vapor resistant materials led to composite systems.

Here, ARCHITECT takes a look back at the available insulation technology of the 20th century.

Click to page through.

Patent Mineral Wool, A.D. Elbers, New York, 1880
Some of the earliest commercial insulation were made of mineral wool, a fibrous material spun from molten mineral or rock components such as slag. Mineral wool could be used to insulate piping and heating systems, as well as in general structures.

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H.W. Johns' Asbestos Steam Saving and Fire Proof Materials, H.W. Johns Co., New York, 1884
The H.W. Johns Co., established in 1858, became a large manufacturer of asbestos insulation, a material noted for its fire-resistance—and later reviled as a health hazard. This catalog promotes the use of insulation materials for boilers and heating systems.

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Celotex Insulating Lumber, Celotex Co., Chicago, 1923
The Celotex Co. produced a variety of building products that it promoted for their insulating qualities and structural strength. The company claimed that its insulating lumber exterior sheathing material was superior to conventional lumber or masonry in reducing thermal transfer, and therefore reduced energy usage.

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The Building Contractor’s Book on Armstrong’s Corkboard for a Heatproof Lining for Walls and Roof, Armstrong Cork & Insulation Co., Pittsburgh, 1926 
Cork has long been recognized for its thermal insulating capacity and noise transfer reduction. The Armstrong Co. produced corkboards that could be used instead of lath for plaster walls.

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Weatherwood Insulation Data Book for Architects, Chicago Mill and Lumber Corp., Chicago, 1931
Weatherwood was one of several competing versions of a structural insulating board made from wood or other natural materials. This publication bills itself as a comprehensive guide for architects offering climate and technical data on insulating materials.

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Facts About Insulation, Silvercote Products Inc., Kalamazoo, Mich., 1936
This guide to insulation is an illustrated version of two technical publications from the American Society of Refrigeration Engineers. Early research on insulation revealed that insulation technology also needed to address moisture transfer and control.

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The Book of Triple Insulated Homes, Johns-Manville Co., New York, 1937
The "triple insulated home" featured a variety of Johns-Manville products that had improved durability and fire resistance because they were made of asbestos. The wall cavities of this hypothetical house were filled with rock wool insulation while the roof and walls featured asbestos-cement shingles.

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Fir-Tex Insulating Boards, Fir-Tex Insulating Board Co., Portland, Ore., 1945
Fir-Tex insulating boards could be used for sheathing but this catalog also features many options for decorative interior finishes.

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Zonolite Brand Vermiculite: Insulation, Lightweight Aggregates, Acoustical Materials, Zonolite Co., Chicago, 1951
Vermiculite is a fire-resistant mica mineral that could be turned into a very lightweight loose-fill insulation for cavity walls or attics. Vermiculite could also be used as an aggregate in plaster or concrete. Unfortunately, these materials could also contain asbestos.

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Reflective Insulation, Louis Hafers Co., Alhambra, Calif., 1961
This reflective insulation featuring aluminum foil attached to a "kraft paper" backing was promoted for its superior reduction of radiant heat, particularly in ceilings.


Rmax Continuous Insulation Shines in Colorado Project

Wed, 2019-05-08 14:59
Building ScienceEnergy Efficiency

When Colorado architects from the Davis Partnership were designing a new building for the non-profit Shiloh House, they were thrilled to find a product that would protect the building envelope from exposure to fire, water, and wind while integrating a continuous insulation system that would provide long-term thermal efficiency. The polyiso wall insulation solution from Rmax gave them flexibility to use a variety of external claddings for visual interest without compromising on protection from the elements and energy savings. Even better, with the help of Rmax’s in-house architect and field team, they were able to design a wall system with smooth, on-time installation that meet the rigorous NFPA 285 requirements.

Shiloh House has five locations across Colorado that offer nurturing, therapeutic and educational services aimed to help youth and families to overcome the impact of abuse, neglect and trauma. They helped over 1,000 youth last year alone. 

This new facility in Centennial is situated on a 1.54-acre property and includes on-site parking, outdoor courtyards, and the spaces and amenities that support the group’s programming to promote family stability and help families achieve their goals, while ensuring continued access to community resources once Shiloh House services have been successfully completed.

For an organization with such lofty goals, every dollar saved in building operations is another resource that can be used to serve its mission. The Rmax polyiso wall boards provide continuous insulation—eliminating heat lost that could occur through the studs when insulating with traditional products that are installed only in the wall cavities—and have reinforced aluminum foil facers that offer enhanced durability, dimensional stability and greater radiant heat protection. They make it easier and less expensive to keep the building comfortable, no matter the weather conditions outside.

“When we’re designing a building, we try to meet the highest standards because we care about protecting the environment and saving our client money over the whole life of their building by maximizing energy efficiency,” the architects explained. “With a reliable weather barrier and superior insulative properties, the polyiso continuous insulation system really gives your building the best protection while actually saving time and hassle on installation since it includes multiple protective layers in a single product.” 

And the finished product speaks for itself:

Aerial views: 

Project Gallery:


Johns Manville Releases New Fiberglass Insulation Board

Wed, 2019-05-08 14:53
Building ScienceEnergy Efficiency

Johns Manville, a Berkshire Hathaway company and leading building products manufacturer, announced today the release of 800 Series Spin-Glas® Ultra, a fiberglass insulation board with a new polypropylene coated (poly-top) facing.

The insulation is designed with a facing that provides a similar aesthetic to Johns Manville’s Micro-Lok® HP Ultra pipe insulation, which also features a polypropylene coated facer. This polypropylene coating allows both 800 Series Spin-Glas Ultra and Micro-Lok HP Ultra to be wiped down for better cleanability.

Lance Bonin, Johns Manville’s Mechanical Portfolio Manager, said the idea for this new facing began at one of Johns Manville’s Contractor Advisory Councils.

“We regularly host events where we can get feedback from the contractors who install our products,” Bonin said. “Over the last year, one thing we heard repeatedly was that contractors want a poly-top facing for our Spin-Glas board insulation that is similar to the poly-top facing we use on our Micro-Lok® HP Ultra pipe insulation.”

The new facer is a scrim-reinforced, polypropylene-coated, metalized polyester.

Meredith Westerdale, Johns Manville’s Mechanical Product Manager, explained that this new facing is unique from other mechanical insulation facings. “Most facings used on mechanical insulation have a kraft paper component, but the new facing we are using on our 800 Series Spin-Glas Ultra board has no paper. We’ve found that for fiberglass boards, this can improve their wrinkle-resistance,” she said.

800 Series Spin-Glas Ultra can be used on any ASJ specification as it meets the requirements of a polymeric film type ASJ per the NIA Glossary. Additionally, it meets the highest rating for low permeance vapor retarders as a Type I classified material per ASTM 1136.

800 Series Spin-Glas Ultra will be available from Defiance, Ohio, in late April. For more information about 800 Series Spin-Glas Ultra, download the data sheet or the FAQs.


Kingspan Moves On After Recticel Rejects Buy Offer

Wed, 2019-05-08 14:48

Kingspan has moved on from its discussions with Recticel over bids for a part or whole of its Belgian rival and sees little hope of a deal being revived, the Irish insulation company’s chief executive said on Friday.

Recticel last week rejected a 700 million euro bid for its two main foam and insulation businesses, and disclosed that Kingspan had also approached it in relation to a possible offer for the entire group.

Kingspan had in fact twice reached agreement to progress to due diligence on a takeover before instead attempting to select the assets it really wanted, CEO Gene Murtagh said on Friday.

Recticel said last week that the approach for the entire group was made at 10 euros per share.

“We had agreement. On two occasions in fact and it’s when that fell through that we made the probably less friendly approach and the conclusion of that was quite predictable,” Murtagh told the company’s annual shareholder meeting.

“I wouldn’t hold out much hope at all (of the deal being revived). It would have been a nice bolt on, but it wasn’t to be... We’ve moved on. Plenty more fish to fry.”

Murtagh said Kingspan first approached Recticel “to do something” in 1994 when his father, current chairman Eugene Muratagh, was in charge.

Kingspan has spent just over 1 billion euros on acquisitions over the last two years, mainly building up a presence in North, Central and South America, while also strengthening its grip on the European insulation market.

Murtagh told reporters after the meeting that Kingspan had a pipeline of potential acquisitions and the capacity to spend 400 to 500 million euros a year on deals.

Acquisitions helped drive Kingspan’s first quarter sales up 18 percent to just over 1 billion euros, the Cavan-based company said on Friday.

While it anticipated “reasonably positive momentum” through the second quarter, it also flagged that insulated panel orders in the United Kingdom, where it generates around a fifth of its sales, have been relatively subdued.

Murtagh said that as long uncertainty prevailed in the UK regarding its departure from the European Union, investment decisions will be curtailed. 


Chicago Waits 70 Years to Overhaul Building Code

Wed, 2019-05-01 17:25
Building CodesDive Brief:
  • Chicago Mayor Rahm Emanuel and the city's Department of Buildings announced that they are making a “comprehensive” overhaul to local building codes, which was last done 70 years ago. City officials have been working with each other on the revamp for more than a year.
  • In addition to adopting the International Building Code’s (IBC) terminology and classification systems, the revised code will include provisions for modern materials; update sprinkler requirements to increase safety and encourage development; add risk-based structural requirements that will take the burden off those building relatively small and simple structures; provide more flexible, cost-efficient rehab codes for historic and other existing buildings; institute green building codes; and introduce seismic codes for critical structures and tall buildings.
  • “We are modernizing our building code for the 21st century to advance sustainability, make construction more cost-effective and continue our city’s reputation for innovative design and world-renowned architecture,” Mayor Emanuel said. The city will begin a phase-in of the new codes on June 1, with full implementation by Aug. 1, 2020.

Dive Insight:

Architects, engineers and contractors are expanding their reaches across state and city boundaries, so it’s much easier for those companies to reduce design and permitting time and head off any future compliance problems if local building codes are similar to ones they’ve used before. The International Code Council’s IBC is about as close as the U.S. gets to a common code.  

In addition to its use in several foreign countries, the IBC has either been adopted or is in use in all 50 states, Washington, D.C., New York City and U.S. territories. The ICC updates the IBC, along with its other codes, every three years. The next updated IBC will be released in 2021. 

There’s no mention yet whether the new Chicago code will provide for the construction of tall wood buildings, but the next edition of the IBC, after a somewhat contentious development process, will include codes for mass timber structures built as high as 18 stories (270 feet). Opponents of the new rules cited fire safety as one of their concerns, but the ICC’s ad hoc committee apparently addressed those and other arguments adequately since the organization’s membership voted in favor of the tall wood construction proposals.  

Each year in the run-up to the publication of a new code, the ICC membership considers new proposals based on code group — Group A, Group B and Group C. The tall wood construction proposals were taken up as part of the Group A development process, and this month the ICC will kick off the review of proposed Group B codes. Next year the ICC will consider changes to Group C, which includes the International Green Construction Code