Energy Efficiency and Building Science News

Q&A: Best Approach for Achieving an R-50 Wall?

Wed, 2018-12-12 16:30
Building ScienceEnergy Efficiency

T. Barker is planning a high-performance house in Climate Zone 7A, where the number of heating degree days reaches 10,000 a year and the January design temperature hits 20 below zero.

Although he is still tinkering with his plans, Barker is leaning toward a design with R-50 exterior walls to make the house as comfortable as possible and to reduce the cost of the mechanical systems. The question is how best to get to that insulation value.

In a Q&A post, Barker asks, “Are there any good reports using actual construction experience comparisons for the cost to build double-stud 2×4 (or 2×6) walls compared to single 2×6 with exterior insulation?”

What reading he’s done so far suggests that most double-stud walls are framed on 24-inch centers. “I would think for the minimal cost difference to stay 16 inches on center you get better drywall finish and shear wall capacity for 2-story construction,” he says.

What does the most recent research show in terms of material costs, construction labor, and pros and cons of each of these two options? Further, are there insulation materials on the market with very high R-value that might be a good fit for his house, such as silica aerogels? Those are the questions raised in this Q&A Spotlight.

Double-stud walls are more practical

Reaching R-50 with a 2×6 wall plus exterior foam takes a lot of foam, says Dana Dorsett, something on the order of 6 inches. That makes construction awkward, and may be a good reason to choose the double-stud option.

“A double stud wall is far more practical, since the distance between walls is flexible — two feet thick isn’t substantially more difficult than a foot,” Dorsett writes. “You have to pay attention to the thermal bridging of the subfloors and band joists, etc., and dense packing cellulose gets harder, making fiberglass (which unlike cellulose won’t sag or settle if you don’t quite hit the target density) perhaps a better option.”

As to Barker’s questions about the most up-to-date research, Dorsett points him to a study by the Building Science Corp. Even though it’s not quite as recent as Barker would like, Dorsett says, it still offers sound advice.

But, he adds, forget about aerogel. “Aerogel is ridiculously expensive, and would be totally wasted as cavity fill,” he says, “but there are commercial products designed for framing edge strips, the primary market being commercial construction with steel-stud curtain walls.”

It’s a matter of builder preference

The choice between a double-stud wall and one with exterior insulation is a matter of the builder’s preference, says Michael Maines.

“The ones who prefer double stud walls and don’t like working with foam say that double stud walls are the best value, and that installing exterior foam is difficult,” Maines writes. “The ones who like using foam say that double stud walls are twice the labor and twice the material, and that installing exterior foam is not a big deal. I’ve had this conversation with many different builders and most of them fall into one camp or the other.”

With that said, Maines has found that exterior foam is the best value when the goal is in the R-30 range. For R-values of 40 or higher, a double-stud wall is a more economical choice. The cost difference between an 8-inch-thick wall and an 18-inch-thick walls is just in the extra insulation.

“There are many variables in the equation,” he adds, “so the answer will depend on your specific situation.”

Nor does the choice between 16-inch and 24-inch on-center framing have a clear answer. While 16-inch framing doesn’t use significantly more material, it does use more, and the extra studs don’t make the building substantially stronger. (Builders of three stories or more, however, are required by the International Residential Code to be framed on 16-inch centers.)

Making the case for R-50 walls?

“Can I ask the big question,” says Walter Ahlgrim. “Why R-50? Given the current prices of fuel, materials and labor in most places, an R-50 wall is unlikely to justify its cost in terms of dollars and cents.”

If Barker is shooting for performance numbers required in a Passive House building, R-50 might make sense. Or Barker may live in an area where the cost of fuel is unusually high. He suggests Barker spend some time with a no-cost computer program called BEopt, developed by the National Renewable Energy Laboratory, to learn more about this options.

Packing R-50 worth of insulation into the walls, and R-100 into the roof, will save about $500 a year in heating and cooling costs, Barker replies, in addition to the C$20,000 in mechanical systems. These savings over 15 years will add up to at least C$25,000.

“Additional costs to superinsulate and seal a 2,200-square-foot house will be approximately C$35,000,” he adds. “I can live with the extra cost for better comfort, a quieter house, and being green (never thought I’d hear myself say that — LOL).”

Fuel is indeed a problem. There is no natural gas available on the site, and while propane is a possibility, it’s expensive. Plus, Barker sees no sense in running gas lines into the house when the future is clearly electric.

Several GBA readers question Barker’s estimates of how much money he will save in HVAC operating and installation costs. Will he really save $25,000 over 15 years?

“I wasn’t clear,” Barker says, “but I’m comparing R-50 ‘superinsulated, super-tight’ against the standard that most decent homes would be built to in this area today, which is about R-24 walls, ACH50= 3.0, etc. This happens to be about the quality my current home was built to 20 years ago, so I use electrical and utility usage from that house to make some of my comparisons. Will it end up being R-35 or R-40 instead of R-50?  Maybe, but it will certainly be far more insulated than R-24.”

“At a whole-wall R-value of R-30 or more, the cost difference between R-30 vs. R-50 whole-walls or an R-50 vs. R-100 in the attic is often better spent on upgrading or fine-tuning the window options,” Dorsett adds. “Walter’s recommendation for maintaining a BEopt simulation as you adjust the design features is a good one. In most climates the heating and cooling loads can be cut to the level where point source heating/cooling can work without taking it to R-50 whole-wall and R-100 attic.”

Choices for exterior insulation

Barker has done some research on the cost of different types of exterior insulation and finds that mineral wool is the cheapest option. To reach R-50, he says, the cost of 12-inch-thick Rockwool would be about US$2.05 per square foot of wall area; EPS (13 inches) would be US$3.59 per square foot; XPS (10 inches) adds up to US$5.47 per square foot.

GBA editor Martin Holladay wonders why Barker might choose XPS for exterior rigid foam when most green builders prefer EPS or polyisocyanurate.

Barker says that he wants to stay away from polyiso because of its reduced R-values at low temperatures and, he suspects, some environmental issues.

Dorsett suggests he consider reclaimed polyiso. “Large industrial and commercial flat roofs are usually insulated with polyiso or EPS, which is often swapped out and upgraded during re-roofing,” he says. “The used foam is ‘gold’ for materials reclaimers — they make a good margin even when reselling it at less than 1/3 the price of virgin-stock foam.”

Plus, he adds, polyiso’s reduction in R-value at low temperatures is probably not as severe as Barker thinks.

Our expert’s opinion

GBA technical director Peter Yost adds this:

It’s surprising to have such a detailed discussion of wall performance without mentioning windows. This is especially true given the difficulty that windows introduce in either a 6-inch exterior foam walls or double-stud walls. What is their performance relative to the walls? What’s the increased difficulty of window installation in thick walls? There are lots of decisions to make, and some careful detailing to manage.

I decided to ask leading Passive House builder Steve Baczek what his preference would be for “superinsulated and super-tight” Climate Zone 7 walls. He provided the drawing at the top of this column, and added this:

“I’d love to tell you there is a ‘silver bullet’ wall assembly out there, but — sorry, I’m not aware of any.

“When it comes to enhanced wall assemblies, the choice is usually between a thicker frame (i.e. 2×8+) or a double wall assembly. I’ve done both numerous times and they each have their pros and cons. What I’ve found generally is that it really comes down to the builder’s perspective.

“I can make either assembly perform well, but builders apply the $ tag to it. If I asked 10 builders, I would likely get a 50/50 split in favor of each. We can debate a lifetime on this, but here’s one of my contentions: We worry so much about the R-value of the wall at the cavity, that we usually neglect the wall at the window.

“Understanding the impacts of whole wall R-value suggests heavy attention to exterior continuous insulation and, more importantly, to the windows. My stepping off point for a high-performance wall is usually a 2×8 24-inch on-center wood-framed wall with R-9 Zip  sheathing. Everything is a bit enhanced, but the number of parts is the same as a code-built wall. So I am essentially paying extra for enhancements, not additional labor. This wall for my climate gets me into a R-40ish+ range. It also usually leaves some money for that very important window upgrade to leverage my whole-wall R-value.”


How to Utilize Blower Door Test to Fix Air Leaks

Wed, 2018-12-12 16:26
Building ScienceEnergy Efficiency

There are two ways to seal potential air leaks in homes: You can either seal seams that you anticipate will leak, or you can seal leaks that become evident when a blower door is used to depressurize the house. This second method of air sealing is known as “blower-door-directed air sealing.”

Blower-door-directed air sealing is a method that was developed in the 1980s by weatherization specialists supported by the Weatherization Assistance Program (WAP), a 42-year-old federal agency that funds air-sealing and insulation work in the homes of low-income families.

Old homes are leaky. Discovering all the air leaks in an older home is tricky, requiring construction knowledge, air sealing experience, and detective work. Most experienced weatherization contractors use a blower door to help find these leaks.

Some builders of new homes perform multiple blower door tests at each home they build, using each blower door test as an opportunity to improve on the previous results. More commonly, a builder will arrange for a single blower door test, to be performed as soon as the home’s primary air barrier is complete.

If a house has a vented unconditioned attic, the primary air barrier usually includes the wall sheathing and the ceiling drywall. Assuming that the drywall contractor can visit the job site to install the ceiling drywall early in the construction process, the blower door test is performed as soon as the following steps are complete: the wall sheathing, roof sheathing, roofing, windows and doors, and ceiling drywall. (If your airtightness target is ambitious, you might conduct a second round of blower-door-directed air sealing after the electrical and plumbing rough-in, wall insulation, and drywall work is complete.)

If the house has an unvented conditioned attic, the first (perhaps only) blower door test would be performed as soon as the wall sheathing, roof sheathing, roofing, windows, and doors are installed.

If a builder simply wants to know the home’s air leakage rate, the blower door operator sets up quickly, determines cfm at 50 pascals of depressurization, and leaves.


Entries Sought for Spray Foam Project Awards

Wed, 2018-12-12 16:19
Building ScienceEnergy Efficiency

Help SFPA honor the work and the workers by submitting your examples of cool, interesting projects that show the best of what SPF in the hands of a skilled pro can do. You might win, and that gets you lots of coverage. If you don’t win, you still get recognized as a National Awards Program Finalist, and we share your projects with other industry publications when they come looking for stories so even in loss you might still pick up a big article somewhere. It costs nothing as a member to submit, and you literally have nothing to lose, everything to gain. Make it competitive, submit a project now.

DETAILS: On February 6, 2019, SPFA will host the Industry Excellence Awards Luncheon as part of the Sprayfoam Show 2019 Convention & Expo. There will be awards in several categories for projects that demonstrate excellence in our industry. A panel of industry experts will adjudicate the selection process through a blind judging process. Judges will not know to whom each of the entries belong, therefore the judging will be solely based on the merit of the project according to awards guidelines.

Projects must be completed between December 1, 2017 and November 30, 2018

Please visit for more info.

Residential Enclosure SPF - Spray foam insulation installed in a residential or multi-family dwelling in assemblies such as interior or exterior surfaces of walls, beneath floors, ceilings, under roof decks, unvented attics, basements, crawlspaces, under-slab or exterior below-grade

Commercial Enclosure SPF - Spray foam insulation installed in a commercial, institutional or industrial building in assemblies such as interior or exterior surfaces of walls, beneath floors, ceilings, under roof decks, unvented attics, basements, crawlspaces, under-slab or exterior below-grade

Roof SPF < 40,000 sq ft - Spray foam roofing systems (foam and coatings) installed on the top surface of a low-slope or sloped roof deck on a residential or commercial building where the total sprayed area is less than 40,000 SF.

Roof SPF > 40,000 sq ft - Spray foam roofing systems (foam and coatings) installed on the top surface of a low-slope or sloped roof deck on a residential or commercial building where the total sprayed area is greater than 40,000 SF.

Specialty Applications - Novel or non-traditional applications of SPF insulation or roofing systems not addressed by the four categories above. These can include applications such as underground piping, storage tanks, theatrical stage sets, etc.

Elastomeric Roof Coatings - Application of elastomeric roof coatings [only] on new roof installations. This category is limited to elastomeric coatings defined in SPFA-102.

Global Foamed Insulation Demand to Grow 5% Annually

Wed, 2018-12-12 16:03
Energy Efficiency

Foamed plastic insulation accounted for the largest share of the market in value terms in 2017. This type of insulation is used in all geographic regions and major end-use markets. Polystyrene, polyurethane, and phenolic foams (in both boards and spray-on applications) are the most common foamed plastic insulation products. These and other trends are presented in Global Insulation, a new study from The Freedonia Group, a Cleveland-based industry research firm. 

Through 2022, foamed plastic is expected to be the fastest growing insulation product, advancing 4.9% annually.Growth will be driven by:

  • strong gains in nonresidential construction – particularly in the Asia/Pacific region – as foamed plastic is the most commonly used material in this market 
  • advances in appliance production, as polyurethane foam is the primary insulation product used in freezers and refrigerators
  • the material’s high R-values, enabling it to gain share from fiberglass and mineral wool products
  • comparatively low installation costs relative to other major materials
  • new building codes in many developed countries that call for dwellings to be more tightly sealed to prevent air leakage 

Global demand for all types of insulation is forecast to rise 4.3% per year to $55.2 billion in 2022, when sales in volume terms, excluding reflective insulation and radiant barriers, will total 31.7 million metric tons.

Thermoseal Launches 3 New Spray Foam Products

Wed, 2018-12-12 15:58
Building ScienceEnergy Efficiency

Thermoseal, llc , a leader in the spray foam industry and the manufacturer of Thermoseal brand spray foam insulation and coatings, announced today that after 4 years of research and development, it has launched 3 new spray foam insulation products including Thermoseal 360, Thermoseal 800 and Thermoseal ONE.

Thermoseal’s objective was to improve its technology by offering the highest quality and highest coverage, most installer friendly spray foam products in the industry.

Thermoseal 360 is a new Ultra-High yield open cell spray foam insulation offering more than 20,000 Board Feet in coverage, while remaining simple to install, and providing one of the most consistent cell structures in the industry. Thermoseal 360 allows its customers to increase their profitability by roughly 25% over other traditional open cell spray foams due to its ultra-high yield.

Thermoseal 800 is a new Ultra-High R-Value open cell spray foam which is a dummy proof, no-mix, simple to install, open cell spray foam with superior cell structure. Thermoseal 800 will allow its installers to achieve an R-Value of 4.5 per inch, or R15 in a 2×4 wall which was not previously achievable by most open cell spray foams on the market.

Thermoseal ONE is a new Ultra-High yield, Ultra High R-Value, one pass, closed cell spray foam insulation that can be sprayed up to 7 inches in one pass. Thermoseal ONE offers an R-Value of 7.2 per inch making it one of the highest R-Value closed cell spray foams available on the market. Thermoseal ONE also passed the Hurricane Wind Uplift test which means it is approved for use in Hurricane zones across the USA.

“With the increased competition in the spray foam industry we realized that it was critical to stay one step ahead of the competition by offering products that will help our customers offer superior products and increase their profitability“ said Richard Ettinger, General Manager of Thermoseal. “After 4 years of R&D we are very excited to be able to offer our customers these three new products.”


CA Builders Detail Their Approach to Net-Zero Homes

Wed, 2018-12-05 17:12
Building Science

Building green homes in Napa requires a combination of abiding by national standards, learning about the local natural environment and being aware of how light and heat change over the course of a day in Napa Valley.

A typical green home rewards its owner by using less energy and water, providing a monthly saving on utilities, and maintaining cleaner indoor air than a conventional home. There are many aspects of green building to consider, from heating to materials to protecting local bird populations.

Mike Zimmer, chief building official of Napa County, said mandatory and voluntary measures affect green residential home construction.

“The California Green Building Standards Code (which took effect Aug. 1, 2009) is the nation’s first statewide green building code,” said Zimmer.

Zimmer said even individuals doing a remodel or a small room addition can review “green elements” of home construction with a contractor.

In California, builders should be aware of the “southwest exposure,” the direction in which sunlight comes into a house.

“It helps if you orient the house so the windows and openings face the southeast. That way, you can take in more sunlight during the day. Not having to turn the lights on early in the morning and late at night saves you energy,” said Zimmer.

Zimmer said people who are low-income or on a budget can get assistance to make a home green by looking to the appropriate agency.

“If you’re retired and on a fixed income, different agencies in the state will repair or replace certain items for free. For example, the California Conservation Corps (CCC) will replace refrigerators, upgrade lighting, and change water fixtures for you. The California Department of Housing will assist with weatherization,” said Zimmer.

Kenneth Russo, founder of Green Builder, a Vallejo-based contractor who builds green homes in Napa, advises several materials for green homes.

Advertisement (1 of 1): 0:11

“When you build where there is a risk of fires, you should use fire-resistant glass. (You should also have) metal shutters on the exterior of windows so you may close (them) and prevent hot (embers) from entering the home. I recommend metal stud construction for homes as well. It’s economical, fire-resistant, and recyclable. It doesn’t get termites or wood rot,” said Russo.

Russo also recommends a roof made of refractive material, which holds heat in during the winter and keeps heat out during the summer.

“It avoids the stack effect which allows infiltration of hot air into enclosed spaces. That way you do not waste heat or cooled air anywhere in the house. (Another thing you can do) is install vapor barriers underneath the home,” said Russo.

Bob Massaro, CEO of Healthy Buildings in Napa, said the best strategy is starting with a “really good building envelope.”

“Summer months in the Napa Valley can get quite warm. We design and build each home’s ‘building envelope,’ walls, floors and roofs, to be very energy efficient. (This way) the residents are always comfortable and…the requirement for using air conditioning is minimized. We also put solar power on our homes to make sure each home produces as much energy as it consumes. In the building industry, that is called ‘zero-net energy,’” said Massaro.

Massaro advises not using wood on the outside of a home.

“It’s combustible and not allowed in many areas because of fire danger. Wood also does not weather well. We use composite materials, metal siding, and ‘Smart Siding.’ These are durable, low maintenance products that are quite fire resistant,” said Massaro.

Jarrod Denton, architect with Signum Architecture, LLP in St. Helena, said if you build a well-designed and constructed home in Napa Valley, you will not need air conditioning.

“Make sure you get high-performance windows and doors. They perform eight-times better than conventional windows and doors. A well-insulated, airtight home is almost like having a Gore-Tex jacket in a rainstorm. Moisture can escape out. Nothing is allowed in unless you choose to open up the window or doors for a pleasant breeze,” said Denton.


RESNET Director Outlines Building Efficiency Goals

Wed, 2018-12-05 17:03
Building ScienceEnergy Efficiency

Ryan Myers, program director for RESNET, recently outlined his top priorities for 2019 in an interview with Edward Keegan.  According to the resulting article, Myers most important responsibility is to increase the number of HERS-rated homes in the U.S. above the current level of 200,000.

Here are a few key initiatives Myers outlined to achieve that goal:

“…get HERS index scores into real estate listings by educating appraisers to recognize the value of HERS-rated homes.

…move toward performance-based codes, noting that the prescriptive path has developed to a point where it’s difficult to get efficiency gains across the board.

…developing a whole-house water efficiency rating with RESNET, which will be an ANSI standard when it’s finished.”

Ultimately, Meres states ratings systems like HERS are a useful tool for builders and designers.

“The projected HERS rating is based on plans and specs,” Meres explains. “We can provide different solutions than the builder may have thought of—by switching out windows or using a different kind of insulation to achieve the same R-value.”

Tips for Designing with Insulated Metal Panels

Wed, 2018-12-05 16:48
Building ScienceEnergy Efficiency

Insulated metal panels (IMPs) are an exterior cladding system that can be used on virtually any type of facility and are commonly found on industrial-type structures such as storage buildings or warehouses.

IMPs offer design and construction teams numerous benefits, such as quick installation, advanced thermal performance and a tight, continuous air/weather barrier. This continuous insulation, which meets the 2015 Washington State Energy Code requirements, also helps minimize heating and cooling costs. 

Editor’s Note: For in-depth information and best practices for designing and installing continuous insulation, check out:

To ensure the building envelope performs properly in structures that incorporate IMPs, designers need to pay close attention to how the IMP system interfaces with adjacent envelope and structural systems to achieve optimal performance. When working with building owners and designers, Nexus bec Inc. focuses on avoiding thermal bridging, selecting the right sealants and correctly sealing penetrations through the IMP system. When these details are specifically addressed, owners can get the most out of this efficient and cost-effective system.

Avoid thermal bridging

Thermal bridging occurs when a material that is more conductive than the materials around it spans continuously from the exterior of a wall assembly to the interior of a wall assembly, effectively creating a bridge through the thermal barrier of the wall that allows for the accelerated flow of heat. This frequently occurs at wall studs and is commonly visible on cold days where framing appears to be “shadowed” on the exterior face of walls.

Any structure is susceptible to thermal bridging, but it is a specific concern with metal-framed structures. The biggest concern is thermal bridging will allow for condensation to occur within a wall assembly or on structural members, frequently resulting in deterioration and organic growth within insulation and on gypsum sheathing.

A completed wall with IMPs is right of the Tyvek wrap. The Tyvek area will have CMU veneer installed, with IMPs over the exposed framing. 

This sealant joint separated likely due to movement of the flashing. 

From an energy-efficiency standpoint, thermal bridging has a significant negative impact on the effectiveness of the building’s insulation. For example, metal-framed walls with only batt insulation can see a reduced effectiveness of the insulation of up to 63 percent due to thermal bridging.

Advances in IMP construction and detailing, particularly in sealing at panel joints, have helped remedy this issue. This exterior cladding system itself is designed to avoid thermal bridging; however, it is still possible to find IMP systems that do not properly address this concern due to insufficient joint detailing, improper roof-to-wall transitions, and transitions from IMPs to other adjacent materials.

Generally, IMP packages are designed as a complete system, but often project-specific details for transitions are left to the general contractor to determine in the field if not properly captured during design. Design-build projects are most susceptible to “gaps” in the details. For this reason, it is important to pay close attention to joint detailing and how well the IMP details allow for integration with adjacent materials when selecting a system.

Selecting sealants

Sealants and self-adhered membranes are a critical component in any IMP system and the role it plays as part of the whole building air barrier. The exterior metal face on the IMP will naturally expand and contract with changes in exterior temperature throughout the seasons or even over the course of a day. This thermal expansion may cause panels to bow and shift, putting tremendous strain on sealant joints, both adhesively and cohesively.

It is crucial the design team specify sealants or self-adhered membranes that provide durability, flexibility and exceptional elongation properties over the life of the IMP system.

When specifying a sealant, design teams must consider the regional and specific micro-climate around the building, taking into account solar exposure of the panels, wind exposure and potential sources of humidity that may impact both the installation and long-term performance of the sealant.

Considerations beyond climatic conditions potentially affecting the sealant and air-barrier performance are structural movement anticipated (i.e. high wind exposure) and the intended use of the building where excessive temperature and humidity may be present on the interior.

These types of conditions may further concentrate performance issues on the sealant joints, which are the most dynamic part of the IMP system. It is important to consult with the IMP manufacturer to make sure the sealant specified has proper adhesion qualities for the intended use, followed with an adhesion test to ASTM standards.

Seal from air and water

Every building will have some sort of punched opening, such as windows and doors. It is essential these openings, along with the transitions from slab/foundation to walls, walls-to-roof assemblies and other penetrations (louvers, vents, electrical junction boxes, security cameras, etc.) are properly detailed to ensure a proper seal for air and water.

The redundancy and layering of built wall systems do not exist in the barrier-type system of an IMP, particularly leaving penetrations exposed to climatic conditions. Since many IMP manufacturers often provide full installation details for their systems, it is easy to overlook these critical, project-specific details. For this reason, the design team needs to work collaboratively with the contractor and perform specific site visits during construction to verify the integrity and quality of installation and detailing in the field.

Achieving energy efficiency

Insulated metal panels are an effective and efficient way to clad a building that not only meets state and local energy code requirements, but also provides building owners with a facility that is air- and water-tight. However, these systems are not perfect and require special attention to the unique design issues outlined above.

With so many factors to consider, Nexus works closely with designers, construction teams and building owners to ensure the components of an IMP system are properly selected, detailed and installed.


Addressing Moisture in Unvented Attics with Spray Foam

Wed, 2018-12-05 16:31
Building ScienceEnergy Efficiency

Editor’s Note: For in-depth information and best practices for designing and installing foam insulation, check out:

To some, unvented attic construction using spray foam insulation is a fairly new approach in home building. With it, the orientation and type of insulation applied to the top of the building enclosure has changed from the traditional way, and so temperature and moisture conditions experienced by various assembly elements will be impacted. As a result, some in the building industry have experienced concern with this construction approach.

Moisture Concerns

Roof Leaks

The issue of water leakage from the exterior is sometimes raised as a concern. From a design perspective, attic venting is not provided to address roof leaks. The basic design assumption regarding all roofing systems is that the roof system deflects water away from moisture-sensitive materials. If it does not do this, it has failed.

Spray foam insulation performance can offer different ways to address problematic situations:

Open-cell foams will tend to leak closer to the point of water entry making leaks easier to identify and locate. Note that not all open-cell spray foam insulations have the exact same physical properties as some are able to absorb a significant amount of water which could aggravate moisture conditions in an attic.

Closed-celled foams will perform better in terms of deflecting water away from interior element,s but in some cases leaks may go undetected longer. Many have been tested as a water resistive barrier.

Vapor Diffusion

The superior air sealing performance of spray foam insulation, both open- and closed-cell, results in moisture movement by vapor diffusion increasing in importance. Building code vapor retarder requirements for unvented attic construction have been in place since the 2009 IRC and have resulted in thousands of successful assemblies that contain spray foam. Closed-celled foams can meet vapor retarder class II requirements at minimal thicknesses, thereby proving a popular choice in Climate Zones 5 through 8 where such requirements apply. In Climate Zones 1, 2, 3, and 4 the use of open-cell spray foam, with their vapor permeable nature, will allow the drying of roof sheathing and framing as diffusion allows moisture to pass through the spray foam out of sheathing and structural elements.

Lately, discussions related to open-cell spray foam in unvented attics, vapor drives and humidity levels have appeared. It appears that many opinions presented are based on limited building science field research, generalize a complicated building science situation, and doesn’t fully explain the continued successful, long-term performance of spray foam insulated unvented attics in hot climates. There is a significant emphasis on computer simulations in these discussions. The movement of air and moisture in real buildings is a complex and dynamic group of reactions that are difficult, if not impossible, to fully and properly model in a computer analysis.

Some roof assemblies use very vapor impermeable materials such as “peel and stick” membranes to cover the entire roof sheathing exterior. Care should be taken with these assemblies in Cold Climate Zones in that the manufacturers of these materials assume that roof deck may require ventilation to assist drying. If spray foam is used in these climates zones vapor retarder requirements apply, drying to the interior is limited, and a vented space may still be needed directly under the roof deck. In Warm Climate Zones, vapor permeable open cell spray foam would facilitate drying of the assembly to the interior, making a vent space under the roof deck unnecessary.

Air Leakage

For unvented attics, having the spray foam layer applied continuously from the roof/wall intersection to the roof peak, at the specified thickness, encapsulating the entire interior surface area of the attic will hinder airborne moisture entry while providing an energy efficient environment. Coverage gaps could lead to moist outdoor air entry, and since a venting system is not place, higher humidity levels could result. Spray foam installers that have successfully gone through manufacturer or trade-association delivered application training are more likely to deliver the installation needed.  

Temperature Concerns

Among the significant issues that get raised pertaining to unvented attics is concern over asphalt shingle temperature/durability in hot climates. Generally, it has been found by researchers that the net impact of eliminating venting is to raise shingle temperatures only by five to eight degrees Fahrenheit. Furthermore, it was found that shingle temperature was affected more severely by factors such as geographic location, roof slope and orientation, and shingle color. The effect on roof sheathing temperatures in unvented attic was similarly shown to be of negligible concern.

But, the lack of understanding of these issues has prompted some manufacturers to reduce or eliminate their warranty on shingles applied to unvented roof assemblies. Were warranties based on scientific evidence, it would be logical that they should also be altered based on geographic location—one should expect to get a different warranty in Las Vegas versus Minneapolis. In any event, a growing number of manufacturers are offering competitive warranties for roofing over unvented attic assemblies recognizing a significant marketing opportunity for their products.

In cold climate locations with significant snowfalls, ice dam formation on roofs is a real concern. The problem is that warm house air can melt the snow on an uninsulated roof when attic venting is blocked. Insulating and providing airtightness with spray foam at the underside of the roof as part of an unvented attic assembly will elevate such concerns.

Spray foam insulation in an unvented attic assembly has been one of the most researched and widely implemented innovations of recent years. Over time, feedback from builders and building owners has been and continues to be overwhelmingly positive, especially in the areas of moisture performance, energy efficiency, and building durability.  


Beacon Roofing Posts 50% Net Sales Increase

Wed, 2018-12-05 16:07

Despite the challenges posed by weather in the fourth quarter, Beacon Roofing Supply's net sales rose 50% year-over-year, according to a news release. Fourth quarter net sales rose to a record $1.9 billion according to the company.

Most of the boost in sales came from the acquisition of Allied Building Products, a deal that was closed in January. Excluding the impact of acquisition related costs and the non-recurring tax reform, Beacon's net income grew 27.8% year-over-year to $84.1 million in the fourth quarter.

Sales in the residential roofing product market grew 17.8% in the quarter, while complementary product sales grew 170.6% over the prior year. Excluding acquisitions, though, Beacon's sales decreased 5.6% in the quarter. The company attributed the decrease to weather-related events.

Beacon said fourth quarter results were positively impacted by price gains across all product lines and improved gross margin performance. Fourth quarter gross margins expanded by 40 basis points compared to the year-earlier period to 25.4%. Gross profit increased 52.3% year over year to $491.3 million.

The quarter results were negatively impacted by existing market sales declines, higher operating costs, and an increase in interest expense and preferred dividend payments that were both primarily related to the acquisition of Allied, according to the company. While the Allied acquisition helped boosted Beacon's sales numbers, it also impacted the firm's costs. Selling, general, and administrative fees went up 60.3% to $328.7 million. Selling, general, and administrative fees as a percentage of revenues climbed up from 15.8% to 17.0% in the July-to-September 2018 quarter. Depreciation jumped 110.3% to 18.7 million and amortization swelled nearly 68%.

Hendron, Va.-based Beacon, the 3rd largest company in the ProSales 100, recorded a fourth quarter adjusted EBITDA—income before interest, taxes, depreciation, and amortization—of $178.3 million, a 34.4% year-over-year increase.

"Despite significant weather impact top-line challenges, we are encouraged by our fourth quarter and fiscal 2018 progress," Beacon president and CEO Paul Isabella said in the news release. "Synergies from the Allied acquisition are exceeding expectations. We will build upon these successes in 2019 by leveraging our 2,000 person salesforce and vast network of over 500 branches to drive top-line growth, supported by the ongoing expansion of our robust digital platform."

Below the operating line, interest expense rose 174% to $37.1 million. The company's balance sheet lists goodwill as making up $2.5 billion of its $6.5 billion in assets. On the liabilities side, long-term debt totals $2.5 billion.

DuPont Launches New Tyvek DrainVent Rainscreen

Wed, 2018-12-05 16:05
Building Science

DuPont Safety & Construction, a business unit of DowDuPont Specialty Products Division, today announced the release of the DuPont™ Tyvek® DrainVent™ Rainscreen to provide advanced protection against moisture damage in exterior wall systems. The product is the business’ first roll good offering that creates a 6mm (0.25”) space for water drainage and air movement for drying behind cladding.

The Tyvek® DrainVent™ can be installed behind stucco, stone veneer, brick, wood, fiber cement and metal panel systems. And helps to prolong the life of exterior cladding by creating a gap that helps prevent rot, cracking and peeling problems. The product replaces the intervening layer required with stucco and stone, while the attached heavy-duty filter fabric prevents mortar and stucco infiltration.

A benefit to contractors looking for time efficient products, Tyvek® DrainVent™ is easy to cut and install, lays flat and rolls tight against corners, helping protect against poor installation and detailing errors. The heavy-duty filter fabric keeps mortar out, helps create a flat surface to allow the cladding to lay flat and has a high perm rating so it is very breathable. Thanks to its unique three-dimensional honeycomb-textured design and durability, it also provides uniform nonstructural support for the various claddings.

“We are bringing new solutions to help our customers build high-performance walls and provide peace of mind for homebuyers desiring the most popular claddings and designs. DuPont™ Tyvek® DrainVent™ helps walls dry by simply letting water drain, and air to circulate behind the cladding, to help prevent long-term damage to the structure,” said Alan Hubbell, Residential Market Manager, Performance Building Solutions, DuPont Safety & Construction. “The new offering is an important addition to our DuPont™ Tyvek® weatherization portfolio and customers can rest assured it will offer the performance, reliability and durability expected from a leader like DuPont.”

Tyvek® DrainVent™ includes a 10-year limited product warranty, and a 10-year limited product and labor warranty if installed properly with DuPont™ Tyvek® wrap and flashing products. For customers to ensure they are eligible for the warranty, it’s recommended that 

Tyvek® water-resistive barriers, like HomeWrap®, be used underneath Tyvek® DrainVent™ rainscreen. DuPont™ Tyvek® Tape and DuPont Flashing Products are suggested as well to ensure optimal building envelope performance. Using Tyvek® full system of products in this way will enable customers to take advantage of the available warranties. In addition to the warranty, the Tyvek® Specialist Network is available across the United States for additional information and customer support.

Tyvek® DrainVent™ also features a Class “A” fire rating per ASTM E84, the standard test method for surface burning characteristics of building materials.


JohnsManville Completes Expansion of TPO Production Line

Wed, 2018-12-05 16:03

Johns Manville (JM), a Berkshire Hathaway company and leading building products manufacturer, announced today the completion of a TPO expansion project in Scottsboro, Ala., to manufacture 12-foot-wide TPO roofing sheets. The announcement comes as the company celebrates the 10-year anniversary of its renowned TPO roofing product and production in Scottsboro, beginning in 2008.

“We are proud of the performance with our TPO product line,” said Joe Smith, president of Roofing Systems at Johns Manville. “Our Scottsboro manufacturing facility plays a vital role in ensuring product availability for our North American customers. This second production line increases capacity and our ability to develop products to meet the needs of commercial roofing contractors and distributors.”

TPO is the fastest growing commercial roofing membrane in the U.S. Now, JM can offer 12-foot sheets and 6-foot sheets. The new production gives contractors working on commercial roofing projects more choices to meet their project needs.

“Our goal is always to offer best-in-class products to our customers and to meet their growing business needs,” said Jennifer Ford-Smith, director of sales for JM Roofing Systems. “The 12-foot-wide TPO is a product that many customers have wanted to buy from JM. We are delighted to add the wider sheet to our broad portfolio of roofing products.”

The expansion project to add a second production line will create more than 25 new jobs in Scottsboro. JM expects more jobs will be added in the coming years.

“This plant has been a dynamic part of the Scottsboro community since 2008,” said Jeff Maxson, group plant manager-single ply for JM Roofing Systems. “A larger workforce means we have more opportunity to participate in state and local community activities. We have long enjoyed supporting local food banks, the American Cancer Society, Relay for Life and other important organizations in the community.”

JM’s 12-foot-wide TPO product will be available in all thicknesses – 45, 60 and 80 mils. The new, wider product became available in early July and is at distribution facilities across the country including Scottsboro, Ala.; Rockdale, Ill.; Hazelton, Penn.; Grand Prairie, Texas; and Tracy, Calif.

Kingspan Wins ‘Top Trusted Brand’ of Insulation Award

Wed, 2018-12-05 15:56

The latest Top Trusted Brands survey by Architecture & Design has once again named Kingspan Insulation as the Top Trusted Brand in Insulation. Kingspan extends their winning streak by topping this category for the fifth consecutive survey.

More than 600 brands were in the running for the awards. The survey collected over 6,000 responses, which ranked their favourite brands in the architecture and design space across 30 categories. Kingspan Insulation has held the title of Top Trusted Brand in the Insulation category since the awards were established in 2012.

Kingspan’s success comes from the fact that the brand provides the widest range of Code-Mark certified insulation products and offers full support through their expert technical and customer services.

Customer responses to the survey explain exactly why it has remained on top of the list for so long.

“Top service, quality products, and excellent technical support. Kingspan are leaders in the industry around the world.”

“I have referred numerous family, friends and businesses onto Kingspan insulation products. Their quality, commitment, honest can-do attitude far outweigh any other product or competitor in the market today. They are of the highest safety standards and will proudly back this with hardcopy records of strict quality control testing and stats. I have dealt with the SA team on a few occasions and I find them highly innovative, trusting and extremely proactive with their service to the wider business community. Kingspan is definitely my top trusted brand for not only 2018 but past and future also.”

“Every time insulation comes into any discussion Kingspan comes immediately to everyone’s mind.”

“Good advice and an honest approach. We have worked in Singapore and Australia and they have an understanding of the requirements for both countries.”

In response, Kingspan Insulation’s Marketing Manager, Neil Cox said that it came down to the company’s commitment to its customers.

“We are always looking at ways in which we can enhance the brand experience to our customers, and the architects and designers who are specifying our products. We offer a full range of technical support and services and that definitely puts us a step ahead in terms of the trust our customers have in our people, our products and our brand.”

Tax Bill Could Make Commercial Roof Retrofits More Attractive

Wed, 2018-12-05 15:52

There is a new tax reform bill which features enhanced deductions under Section 179 that lower the cost of commercial property improvements, including the roof. This could be a game changer when working with commercial establishments looking to get a new roof or do repairs or even for your own buildings.

This recently modified Section 179 expands the definition of eligible property and increases the amount of associated costs that may be expensed as of January 1, 2018. Certain updates to nonresidential property, including roofs, may now be fully expensed in the year of purchase, rather than depreciating the cost over 39 years.


You repair a small section on one corner of the roof of a rental house. You deduct the cost of the repair as a rental expense. However, if you completely replace the roof, the new roof is an improvement because it is a restoration of the building. You depreciate the cost of the new roof.

Some other changes include the maximum amount that may be immediately deducted from $500,000 to $1 million and increases the phase-out threshold from $2 million to $2.5 million. These new limits may be effective for qualifying property beginning after December 31, 2017 and will be adjusted for inflation following 2018.

We encourage you to talk with your tax professional to see how this may help you and your related sales towards Commercial roofing and insulation!

2020 Polyurethane Conference to be Held in Chicago

Wed, 2018-11-28 16:35
Building Science

Organizers of UTECH North America, the independent polyurethanes conference and trade show, today announced that the next edition of the event will take place May 19-21, 2020, at the Renaissance Schaumburg Convention Center Hotel in Chicago.

“Our attendees and exhibitors spoke, and we listened,” said Debbie Hershfield, Trade Show and Events Director, Crain Global Polymer Group. “The show’s new location will make travel easier than ever for polyurethanes professionals and suppliers traveling from across North America. We’ve already had a lot of positive feedback on the new location and are confident this will be one of our best events to date in North America.”

UTECH North America draws from a broad range of polyurethane professionals representing numerous industries innovating with polyurethane. This includes automotive, aerospace, building and construction, electrical, furniture and bedding, footwear and textiles, mining and offshore, pipes and pipelines, refrigeration and insulation as well as specialist surgical and medical.

Held in conjunction with the conference, the independent UTECH North America trade show connects suppliers and buyers from across the polyurethane industry for two days of networking, learning and identifying new business opportunities. As the only show that is 100 percent polyurethanes, attendees can expect to meet with leading suppliers, including REPI, Chromaflo, Frimo and Max Process Equipment.

To stay up-to-date with the latest information and details for UTECH North America 2020, please visit the event website at: http://www.utech-north-america.comImages and video from UTECH North America 2018 are also available on the event website.


IgCC 2018 Designed to Align with LEED

Wed, 2018-11-28 16:28
Building CodesBuilding Science

The 2018 version of the International Green Construction Code (IgCC) is designed to align seamlessly with LEED.

The code is developed by a coalition of partners, including the U.S. Green Building Council (USGBC), The American Institute of Architects (AIA), and ASHRAE.

Resilience, EV charging, and required renewables

What’s different about the 2018 code?

First, it looks a bit different because there are two numbering systems. That’s because the code has been completely harmonized with ASHRAE 189.1, Standard for the Design of High-Performance Green Buildings Except Low-Rise Residential Buildings. “This version has basically combined the two documents into one,” explained Wes Sullens, director of codes technical development at USGBC. “The standard will exist on its own in markets” internationally, he said, but for all practical purposes, in the U.S. and Canada, the IgCC and ASHRAE 189.1 are one and the same.

USGBC envisions a time when widespread green codes are the foundation of voluntary LEED certification.

As for substantive changes, there are a few of those as well, many designed to align the code more closely with LEED.

“Resilience is now added to the scope as a discrete desire or goal for the code,” said Sullens, who pointed to things like building controls, site design for passive energy strategies, and certain aspects of commissioning “that hopefully allow for better use of buildings in case of interruption.” He added, “There’s not a chapter on resilience” that anyone could point to, but “we spent a lot of time on the committee talking about what does that mean to be a resilient space.”

Other new requirements include:

  • either electric-vehicle charging or preferred parking for green vehicles
  • pre-plumbing for dual-flush bathroom fixtures
  • a new definition of alternative sources of water, with recycled water no longer recognized (“You have to find that water through storage or other means,” Sullens said)
  • real-time displays of energy use for building managers
  • post-occupancy planning for an indoor air quality survey
  • a small amount of onsite renewable energy (although there is an alternative path that does not require this)

Barriers to adoption

“The ultimate goal is to get adoptions,” pointed out Dave Walls, executive director of sustainability programs at the International Code Council, speaking at a reception at Greenbuild 2018 in Chicago. Although many jurisdictions have adopted some version of the IgCC, he said, “a lot of jurisdictions were struggling with how to adopt it and how to comply with it.”

One issue that hinders adoption is the sense that codes should focus on life-safety issues, but Walls disagreed with the notion that the IgCC doesn’t address life safety. By helping buildings avoid contributing greenhouse gas emissions, the code directly affects health and safety, he argued, pointing to heat waves, drought, fires, and floods as examples of life-safety issues that stem from climate change. “Green codes work hand-in-hand with the safety codes,” he said.

Another issue that hinders adoption is confusion about how the code relates to LEED certification, which some jurisdictions require already. That’s why USGBC has released a chart showing how closely the new IgCC aligns with LEED, with all the LEED prerequisites and 20 points’ worth of credits being easily achievable with the code, making LEED certification easier after that.

LEED will also use alternative compliance paths to align with the code, much like what’s happened with CalGreen, the green construction code in California, according to Sullens.

We can get there from here

Sullens emphasized USGBC’s mission of green buildings for all and said that’s why the organization participates in green code development. “LEED really needs the codes to pick up the core strategies in order for us to keep innovating at the top,” he said. “Otherwise, we’re going to lose the market.”

He said that the coalition working together on development “sends a powerful message,” adding, “It’s all part of a spectrum that we’re all promoting.”


Sustainable Community Rating Incorporated into LEED

Wed, 2018-11-28 16:16
Building ScienceEnergy Efficiency

Today, the U.S. Green Building Council (USGBC) announced that the STAR Community Rating System, which offers certification for sustainable communities, will be fully integrated into USGBC’s LEED for Cities and LEED for Communities programs. This integration will help advance healthy, green and economically strong cities and communities – and reflects USGBC’s partnership with STAR Communities, the non-profit that runs the STAR rating system.

USGBC’s LEED for Cities and LEED for Communities programs provide third-party verification of the current performance of built-out cities and communities.

“Integrating the STAR Community Rating System into LEED for Cities and LEED for Communities, will bring us closer to our goal of advancing sustainable cities and communities around the world,” said Mahesh Ramanujam, president & CEO, USGBC. “We are helping cities develop responsible, sustainable and specific plans for energy, water, waste, transportation and many other factors that contribute to raising the standard of living for all people around the world.”

The 75 cities and communities that have achieved STAR certification and the 20 additional cities and communities that are seeking STAR certification will now transfer into the family of LEED for Cities and LEED for Communities. Hilari Varnadore, the director of the STAR Communities program, has also joined USGBC as the director of the LEED for Cities and LEED for Communities programs.

“STAR has been a longtime collaborator with USGBC,” said Hilari Varnadore, director, USGBC. “In fact, the STAR Community Rating System was inspired by LEED, and developed with LEED in mind. Through this integration, these exceptional STAR communities will reach an even higher level of leadership where they will be able to benchmark their current performance, home in on targeted metrics to achieve continuous improvement, and demonstrate a commitment to sustainability, human health and economic prosperity. They also send the signal to city planners and policy makers that radical transparency and accountability are necessary to ensure a new generation of places where people, nature and businesses can all thrive.”

The City of Columbia, S.C., was recently certified under STAR. “As mayor of the City of Columbia, South Carolina I could not be more pleased that our city’s performance – and continued commitment to improve that performance – qualifies us to join the illustrious ranks of LEED cities around the world,” said Mayor Steve Benjamin, also Chair of the U.S. Conference of Mayors. “Our STAR certification – earned last December – has provided a great foundation for future work with the U.S. Green Building Council, and we look forward to openly tracking and communicating our continued social, economic and environmental performance so that the people of Columbia can be assured of our measurable progress.”

The development of equitable, safe, healthy, sustainable cities and communities at USGBC dates back to the development of LEED for Neighborhood Development more than a decade ago. As new technologies are developed and new strategies devised, there is a growing consciousness of the collective role sustainability plays in human health and wellness.

“At USGBC, we have a vision that buildings and communities will regenerate and sustain the health and vitality of all life within a generation,” added Ramanujam. “In order to realize a sustainable future for all, the next generation of green building must focus on the development of smart and resilient cities and communities. Our cities must champion equitable, safe and healthy development policies; advanced technologies that improve the performance of their communities and cities; and incorporate concepts like wellness and human experience into city planning, development and management.”

Cities and communities face many challenges in this day and age—citizens are demanding more transparency and information about the places where they live, work, learn and play. LEED for Cities and LEED for Communities address these concerns on a global scale.

LEED for Cities and LEED for Communities programs are helping to accelerate the leadership now being shown by city and community leaders. LEED helps cities and communities benchmark current performance, track performance metrics, communicate continuous improvement, educate residents, visitors and business owners to demonstrate commitment to sustainability, human health and economic prosperity. As a result, local governments are becoming laboratories of innovation and leadership, and have an enormous opportunity to initiate a dynamic dialogue with citizens—and earn their trust in the process.


NYC Group Focuses on Building Envelope to Lower Bills

Wed, 2018-11-28 16:04
Building Science

In recent years, average rent for a one-bedroom apartment in Brooklyn’s Bushwick neighborhood has skyrocketed to more than $3,000 a month, excluding utilities. That’s why New York City’s Department of Housing Preservation and Development (HPD) and Ridgewood Bushwick Senior Citizens Council (RBSCC) came together to develop Knickerbocker Commons.

RBSCC also wanted to cut tenant utility costs radically without compromising comfort. So, they called upon Chris Benedict, R.A., to design an ultra-low energy building. Henry Gifford, who works for Chris Benedict, designed the mechanical systems for the building. The team combined several technologies, such as continuous exterior insulation, energy recovery ventilators, sealed combustion boilers, and individual room thermostat controls, including Danfoss thermostatic radiator valves (TRVs). According to Gifford, the result is 90 percent lower energy consumption than comparable buildings — and heating costs below $50 per apartment per year.

“The 803 Knickerbocker Avenue building was completed in 2014,” says Gifford. “We used proven building-science concepts that could be applied to any high-performance building. No energy-efficiency rebates defrayed the cost of the low-energy technology we used. In fact, we delivered an extreme level of efficiency and comfort without adding to the construction cost.”


Known for his life-long passion for building science, Henry Gifford attended the first class in the U.S. on ultra-low-energy building principles known as “Passive House.” According to Gifford, who recently published the book Buildings Don’t Lie: Better Buildings by Understanding Basic Building Science, “If you understand the underlying science, you’ll have the tools to improve buildings from the start.”

The Passive House principles use a continuous air barrier and exterior insulation. These construction techniques eliminate thermal bridging, creating an interior space that can maintain a comfortable temperature. Natural light and human activities keep the space generally warm; mechanical systems handle domestic hot water production and extreme hot and cold conditions.

When energy prices in Europe more than quintupled in the early 2000s, the “Passivhaus” idea took off — with more than 25,000 buildings on the continent meeting the voluntary, ultra-low energy building standard by 2010.

In the U.S., energy cost hikes were not that extreme, but rising. In 2011, Gifford and Benedict were presented with two projects ideal for the unique design approach, one of which was Knickerbocker Commons.

“It’s not merely about meeting a standard, but simply implementing the smartest possible building-science principles,” says Gifford. “That means integrating all building systems — insulation, water, lighting, and heating, cooling, and ventilating — into a cost-effective, holistic solution. That’s why a device like the Danfoss thermostatic radiator valve plays a big role in creating a comfortable, energy-efficient building.”


One of Gifford’s design principles is that each room should have its own thermostat.

Gifford explains: “If a simple building with only two rooms is located where the sun shines from one direction and the wind blows from another direction, the heating and cooling loads will vary between rooms. Putting a single thermostat in one room will keep that room warm, but leave the other too hot or cold. Plus, internal loads will vary depending on cooking, showering, computers, and lighting. The temperature imbalance becomes very noticeable if the building is well insulated. People will run space heaters in winter to heat up the cold room, and/or open windows in a hot room. That’s a huge waste of energy, and it makes the air dry and unhealthy.”

To avoid balance problems, Gifford provided each room at 803 Knickerbocker with a radiator controlled by its own individual thermostat.

Gifford observes that “individual room temperature control makes the whole apartment comfortable without wasting energy by overheating or overcooling. This allows the system to be downsized, which

saves enough money to more than pay for the additional thermostats.”

To regulate the flow of hot water through the radiators, Gifford employed Danfoss RA2000 TRVs with a tamper-resistant non-electric operator. The RA2000 TRV is designed for hot water or low-pressure steam. In this case, Gifford applied the valves on wall-mounted baseboard radiators to avoid coordination hassles between flooring installers and plumbers.

The TRV regulates hot water flow by using an integrated thermostat and valve assembly. A white knob containing a sealed capsule filled with a heat-sensitive vapor charge functions as the thermostat. If the room is too warm, the rise of temperature increases the vapor pressure in the bellows, closing the valve;

if cold, the pressure decreases, opening the valve. In typical operation, the valve is not either fully opened or closed. Rather, it modulates between open, closed, or partly open based on a proportional difference between actual and desired temperatures.

With the TRV, controlling space temperature is easy; the apartment resident turns the knob to the desired temperature. The dial is scaled in five increments about 5°F apart, ranging from 57°F to 79°F. Gifford set the upper temperature limit to 73°F, but residents can lower the temperature setting, if desired.

“Psychological studies show that when people have control over room temperature, they tend to be more satisfied with their environment,” he notes. “That’s particularly valuable in mild weather when controlling temperature is difficult and a lot of energy is wasted due to overheating.”


Utilizing room thermostat control into the integrated building design has produced extraordinary energy savings. Despite its 34,581 square feet, the property’s peak heating load is only 127,000 BTU/hour.

“This is an incredibly low heat load for a building of this size,” says Gifford. “But, just because the load for space heating goes down doesn’t mean the domestic hot water load is reduced. We put two small, sealed-combustion gas boilers in a mechanical room on the roof. The boiler capacity is primarily used to make domestic hot water and, secondarily, heat the building — which is opposite from the responsibility of most boilers in other buildings. We have four storage tanks for the domestic hot water, and we use the smallest, most efficient pumps possible to circulate water in the hydronic loop.”

A 1/8-horsepower pump supplies a two-pipe hot water system, which runs whenever the outdoor temperature is lower than 55°F, serving the entire building. The Danfoss valves on each radiator control flow through each radiator.

The bottom line for the Passive House design: The space heating cost per apartment averages about $44 per year in a building constructed for the same cost per square foot as any other NYC affordable housing facility.

The ultra-low energy performance, comfort, and aesthetics of 803 Knickerbocker have been widely recognized. It was the first midsized apartment building in the U.S. to be certified to the Passive House standard, and was recognized in New York City Mayor Bill de Blasio’s One City Built To Last program as an innovative approach to reducing the city’s carbon footprint.

The building is further proof that an integrated, holistic approach to design is practical. It also has helped spur changes in NYC building code and zoning regulations to enable construction of more ultra-low energy buildings.

However, most important to Gifford is the legacy of comfortable tenants and property owners. Gifford notes, “Danfoss TRVs have been successfully used for decades, especially in Europe, where it seems almost every room has its own radiator control. Since 803 Knickerbocker opened in 2014, there have been zero tenant complaints about heating. When you can make both tenants and property owners happy in Brooklyn, it shows using thermostatic radiator valves for every room really works.”


Video: Local News Covers Spray Foam Installers

Wed, 2018-11-28 15:50
Building ScienceEnergy Efficiency

In this video, a local crew shows how they install high-grade spray foam insulation to help keep a house warm during the winter. This video is the seventh in a series by a New Mexico news station looking at how homes are built.



Knauf Insulation Completes Mineral Wool Facility Upgrades

Wed, 2018-11-28 15:46
BusinessEnergy Efficiency

Editor’s Note: The article below details Knauf Insulation’s investment in mineral wool production capacity; finishing upgrades in Wales while also building new production facilities in France and Malaysia.

Knauf Insulation has completed a £7 million upgrade of its manufacturing plant in Cwmbran, South Wales, which will increase its capacity by 6%.

The improvements include a complete rebuild of the furnace at the heart of the plant. The work has been completed as part of a £200 million investment programme to significantly increase the company’s manufacturing capacity and capability, which includes the construction of new plants in France and Malaysia.

“We’ve seen increased demand over the last 18 months as architects, contractors, developers and regulators have recognised the benefits of high-performance, non-combustible mineral wool insulation,” said John Sinfield, managing director at Knauf Insulation. “All indications suggest this trend will continue, which is one of the reasons we’ve invested in this comprehensive upgrade of our Cwmbran facility.”

The programme of work at the plant was scheduled to take six weeks, but was completed three days early. It included a complete rebuild of the furnace, and plant-wide refurbishments and modifications taking advantage of the latest technology developments to maintain high product standards. The programme also includes energy efficiency improvements with new compressors, drives and motors installed, which will reduce the plant’s CO2 emissions by just under 7,000 tonnes per year.

During the works, the plant’s 207 employees volunteered their time with local charities under Knauf Insulation’s ‘Community Matters’ programme. In total, 576 hours were given over to supporting four local causes, including two hospices, a resource centre for people with learning disabilities, and an animal rescue facility.

Knauf Insulation’s Cwmbran plant manufactures Glass Mineral Wool for use in a wide variety of applications. Products made at the site include the Supafil range of blowing wools for cavity insulation, and the Earthwool range of high-performance rolls, and slabs for use in traditional and off-site construction.

Knauf Insulation’s new Rock Mineral Wool plant in France is expected to come online in 2019, with the new Glass Mineral Wool plant in Malaysia following in 2020.