Wall Assemblies for Maximum Efficiency: How Many Layers is Too Many?

SimplexOPTIMABuilding professionals spend a lot of time dealing with production construction which has dialed in efficiencies and productivity to provide the maximum assembly for the cost per square foot.  The reality is in standard construction you build things in five or six layers. This is the standard in terms of building a wall system more efficiently and we have gotten it down to a science.  Generally a six layer home will give you a solid, energy efficient, comfortable home.

Occasionally, I work with builders on projects that remind me of possibilities beyond what is the status quo.  I recently had an opportunity to work with a builder who was building a custom home whose wall systems had 13 layers.  This wall had so much redundancy and robustness built into it that I just had to ask for a chance to visit the project and see this masterpiece being built.

This was the homeowner’s instruction: They wanted a thick wall, they wanted a silent wall, they wanted a highly efficient wall for them to own.  That’s one of the key’s to this discussion- the owner is focused on what comes afterwards- not what happened before. To achieve this goal the builder is employing a combination of traditional masonry materials and cutting edge products and systems.   

In a similar fashion, a project that CertainTeed has been involved with at the Navy Yard in Philadelphia with Penn State achieves a similar goal but in a lighter and perhaps less massive assembly – to create a highly efficient wall system that can provide comfort, improve indoor air quality, better acoustics but, and here’s the rub- to still be affordable by more typical consumers.  This was done by using a 2 x 8 construction – providing a deeper wall cavity – A Blown-in-Blanket Insulation System, Weather Resistant Barrier, a Smart Vapor Retarder and Air Barrier System, a Wallboard Solution, Rigid Insulation on exterior and Insulated Vinyl Siding. This created an R30.5 exterior wall.

In both homes, products were used to address acoustics, indoor air quality and moisture control.  Do you need 13 layers?  Probably not but the pressure is certainly going to be on what layers remain to do more than they have in the past.

Thoughts?

 

A Tip for New Home Buyers – Consider What is Behind the Walls

Hybrid insulation installDuring the 2013 International Builders’ Show I had the chance to speak with a regional manager for a national builder about the challenge of helping consumers understand the features, benefits and return on investment (ROI) on the hidden features in a home. 

When a potential homeowners speaks to a builder they are usually more focused on considering upgrades that are visible to the eye than considering what’s underneath the walls of the home. What they don’t consider is how upgrading the R-value in their walls will save them money on heating and cooling over the life of the home or if they plan on selling the home in the future, how this improved performance may help them compete against homes that will be built between now and then.

The challenge that is faced by a builder as well as a solution provider is to create ways to have that very conversation with the consumer in a clear and relatively quick manner. The reality is that a builder only has so much time with a prospective buyer of a new construction and they do have a great deal of ground to cover.  It is usually easier to focus on what is visible than what is not.

During our chat, we discussed creating scenarios of building a house three different ways to maximize the efficiency of the home and how to show that to a prospective buyer.  You could have partially finished walls in the garage of a model home which show building and insulating a wall to code vs. improved materials and techniques.  You could then show various types of wallboard – yes there are varieties of wallboard that address noise reduction, mold and moisture control and volatile organic compound removal.  This could be a chance for people to actually see and understand what is usually hidden behind the finishes they have been focused on.

Truth is, potential homeowners seem more interested in talking about the aesthetics of countertop materials than increasing the efficiency of their wall systems. Why are we so comfortable being ignorant about one the most important investments of our life? I would bet that more people have researched the features and benefits of their next car in terms of gas mileage, horsepower, etc.  than researching the type of insulation and wallboard to use in their home for optimum comfort and health.

Does anybody have any ideas of how we can engage homeowners in the conversation about the energy efficiency options in homes that will lower their operating costs over the life of a home? If you are a realtor, what do you do?

Can We Design Buildings for Heat and Cooling that Mimic the Human Body

Lucas Hamilton

Lucas Hamilton is Manager, Building Science Applications for CertainTeed Corporation

I spend lots of time thinking about buildings. Sad; I know. Lately I have been wondering how we wound up in such a confusing state. It’s like looking under your car hood. Have you looked under your hood lately? It looks like a building design. Who in their right mind would have started out to design such a complicated mess? No wonder we need so many building scientists and we pay a hundred bucks an hour to get our cars fixed. Can we step back for a minute?

Thermal comfort in the built environment needn’t be so complicated. If we could start from scratch and try to make buildings comfortable based upon our own organic experience, what would we do? I live in Philadelphia.  If I go outside in the winter and try to passively stay comfortable – passively meaning to not use any outside energy sources – I would use lots of layers of clothing, would zip up tight and cover my skin.

Coincidentally that is what we require in our cold climate building codes.  Lots of layers of clothing means R-value. When you wear lots of layers of clothing you are trapping gas inside layers.  The gas is the insulation – gas gives you resistance to conductive energy heat flow – that’s R-value.  So when you are wearing lots of layers you are wearing R-value. When we say zip up – that’s getting air tight. We finally woke up and added that one to the cold and mixed climate codes as well.

The problem comes in the summertime. To stay cool, you would take off those layers, wear light colors and try to get air flow around you.  You would wear airy fabrics to release as much heat from your body as possible and light colors which don’t get hot in the sun. If you were stuck wearing lots of layers and were zipped up tight, you would have to blow cold fresh air into that outfit to stay comfortable. Our goal should be not to do that. Remember, passive technologies rule and active technologies cost $$$.

We need to find ways to help a building be warm in the winter and stay cool to begin with in the summer. I am looking for changes to our practices that will enable us to do to buildings what we do to ourselves. How would you build your building differently?

If you can’t strip off all the layers of clothing the very least you will do is unzip so can we figure out a way to unzip our buildings? I know we want to be air tight in the winter but can we figure out a way to use air to remove surface heat in the summer? I think ventilated claddings may be one answer.

Can you think of some others? To go back to the car analogy, let’s stop bolting more stuff onto the internal combustion engine to make it more efficient and drop in an electric motor. It needn’t be so complicated.

Rules Matter When it Comes to R-Value

Ken Forsythe

We all know there are ‘rules’ that everyone might not follow to the letter: “Speed Limit 55”…”Do Not Remove Mattress Tag Under Penalty of Law”…”Lather, rinse, repeat.”  When it comes to heating and air conditioning ductwork, there’s another rule many insulation contractors rarely follow:  “When installing bubble wrap insulation on ductwork, secure spacers every 24” to 36” around duct before applying wrap.”

While there’s no harm if you skip the “repeat” step when washing your hair, there can be serious utility bill consequences if installers leave out the placement of spacers between a duct and bubble wrap insulation. Bubble wrap insulation needs the thermal break provided by the air space that is created by spacers to achieve advertised R-values.  The actual R-value of improperly wrapped (i.e. no air space) duct with bubble wrap can be as low as R-0.90 to R-1.1.  Building Inspectors and owners need to be aware of what to look for to insure that the product performs properly.

In checking with HVAC insulation distributors to determine if insulation contractors routinely purchase air spacers with their bubble wrap, the answer is often “We’re still on our first shipment of spacers” or an outright, “We never sell any of those.”

Often bubble wrap insulation manufacturers do include spacer instructions with options for installers to create their own spacers by cutting and placing 2” wide strips of bubble wrap around the duct in intervals before applying the wrap around the duct or applying corner spacers specifically made for the purpose at each corner of rectangular duct.  But with so much pressure on insulation contractors to keep labor to a minimum, it’s hard to imagine that the vast majority are taking the time to create or use spacers on every project. Let’s face it: installers care about installing as quickly as possible for the lowest cost.

It’s true that quality bubble duct wrap may have good reflectivity and provides some protection against conductive heat gain or loss – as does fiber glass duct wrap with FSK (Foil-Scrim-Kraft) facing – however, the bubble wrap industry needs to do a better job educating installers and/or HVAC contractors. Educating the industry about the science behind adding air spacers and their integral role in delivering promised R-value is an important first step and is in everyone’s best interests.

 Ken Forsythe is a Senior Product Manager for CertainTeed Mechanical/Industrial Insulation

Hybrid Insulation Systems Give Best of Both Worlds in Performance

While making a presentation recently at the Oakland Space and Science Center in California, the topic of fiberglass versus spray foam insulation came up and was quickly followed by questions about hybrid insulation systems. It seems like a lot of people have hybrids on their mind these days.

One of the positives about spray foam is that the insulation itself is air resistant.  The gas or air which does the majority of actual insulating is trapped in bubbles inside the plastic foam matrix and can’t be washed out by air flow.  Now that we recognize the influence of air leakage on a home’s energy consumption, many builders and homeowners are trying to get their houses as “tight” as they can. Installing spray foams where air is leaking through the building envelope can reduce that flow rate. One of the issues people struggle with when considering foams as a solution has been their cost- they can have a significantly higher installed cost than fibrous insulations.

For this reason, in some markets, contractors are turning to hybrid insulation systems often referred to as flash and batt insulation. To fill a 2 x 6 inch empty wall cavity, first add a flash coat of closed cell foam on the exterior wall to a thickness of 1 -2 inches then take a low density batt to fill in the space before the drywall is installed. What you get is the best of both worlds – the inexpensive high R-value of the fiberglass batt combined with a smaller amount of foam which gives you the air tightening effects desired. 

An even more effective option is using loose fill insulation such as OPTIMA® in the hybrid system instead of fiberglass batts.  This is a cost efficient, high R-value, well performing system. A challenge for the hybrid approach lies in very cold climates. Fiberglass is a very efficient insulating material so if too much is used with the foam it will make the foam cold and moisture can form in the wall assembly. That needs to be avoided at all costs. For colder climates there are very specific recommendations for the amount of foam you need to use in the wall constructions before you can eliminate the need for a vapor retarder on the warm-in-winter side of the insulation. We have recommendations for hybrid insulation systems, as does the Blow-in Blanket Contractors Association (BIBCA), designed to create the appropriate foam to fiberglass ratios which will prevent this from occurring. If you choose to install less foam and more fiberglass or if you have any lingering concerns about moisture in these assemblies, I recommend installing a Smart Vapor Retarder such as the MemBrain™ product. As an example, the First LEED Platinum Home in Colorado applied the hybrid system using CertainTeed products.

If you are using a hybrid insulation system in your construction projects I would love to hear your experiences.

Lucas Hamilton

Lucas Hamilton is Manager, Building Science Applications for CertainTeed Corporation

Green Generates Green for Philadelphia Builder

Lucas Hamilton

I had the pleasure of listening to Tad Radzinski, of Sustainable Solutions, a sustainability expert in the Philadelphia area, talk about an unusual and creative project that he recently worked on using a vegetative roof. 

From the Building Science perspective, what I like about vegetative roofs is the albedo of plants, which plays a large part in the benefit of live roofs, and the fact that they are literally cool roofs that naturally increase the insulation value on your structure (the r-value of the soil bed). Live roofs also reduce the amount of storm water runoff and city’s like Philadelphia are starting to reward building owners for moving to vegetative roofs.

 A few facts:

 1.) For most of us on municipal water, when you pay for a gallon of water you are also paying for a gallon of sewage treatment.

 2.) In older municipalities, the storm water and sewage lines are co-mingled.

 3.) When there is a rain event it can cause the water/sewer to overflow system capacity and be diverted into the rivers.

 4.) When this occurs, the municipality is fined for the overflow.  However, most cities would rather pay the small fine from the occasional rain event than to upgrade the storm water and sewage system.

Philadelphia recognized this and has started to reward builders who take steps to reduce site run-off by reducing the per gallon rate paid for the water they do use. By demonstrating the volume of run-off eliminated through the implementation of vegetative roofs and the reduction of hard surfaces such as paved parking areas, builders can qualify for water rate reductions. Applying this data to a life cycle assessment, we quickly see one more way that being green can save you green.

Lucas Hamilton is Manager, Building Science Applications at CertainTeed Corporation

Don’t Skimp on Insulation

Spray foam insulationOn February 5, Martin Holladay from Green Building Advisor.com posted a Blog entitled “It’s OK to Skimp On Insulation, Icynene Says.” This was in response to open-cell spray foam manufacturer, Icyene’s position advising builders to install less insulation than the code requires and for building officials to approve insulation that doesn’t meet minimum R-value requirements.

Martin makes some very good points regarding the flaws in this thinking.  Icynene’s position is that air-tightening a home will have a significant impact on the energy consumption of the home–which is absolutely true, but they are also saying that by doing this you can accept lower R-values.  There is no reason to accept lower R-values.  Builders should be able to do both:  air-tighten a home and have the R-values that the code requires.

Heat moves to and from a home in three ways simultaneously; conduction, convection and radiation.

R-value just deals with conduction and not with air loss.  So to say that building code officials can reduce our requirements on conduction because we are helping to deal with air leakage is a weak argument.  Why should we settle for less? The building code requires that homes be air sealed and have a minimum R-value. There is a reason for that. We have to deal with all three modes of heat transfer simultaneously.

Martin points out that there is language in the 2006 International Residential Code (IRC) that gives air sealing requirements.  Here are a few examples Martin publishes about where buildings are to be air-tightened:

  • Sealing all joints, seams and penetrations;
  • Sealing around windows, doors and skylights
  • Sealing openings between window and door assemblies…

These are not places we put thermal insulation. Putting insulation between two studs doesn’t even address what the code language is saying as to where buildings need to be air-tight.  Different measures need to be taken.  If you look at Icynene’s argument you might infer that because they are air-tightening between two studs they can reduce the R-value required between those studs or in the attic.  There is no reason to accept that.

We consumers can and should have both air-tightness and high R-values because energy is too important to have less than what the code requires. 

Lucas Hamilton

Lucas Hamilton

Lucas Hamilton is Manager, Building Science Applications at CertainTeed Corporation. 

It’s About Systems Not Just Products at Greenbuild

Lucas Hamilton

Lucas Hamilton

I’ve noticed a trend in trade show booth design incorporating computers that show visitors products via websites. This technique cuts down on the amount of materials being shipped to and from show sites.  CertainTeed has tried that as well.

But as I watch and talk to people at trade shows, I’ve noticed that they want to see and more importantly, touch products.  So CertainTeed has decided to go in a different direction with our booth (921) at Greenbuild, November 11-13, in Phoenix, AZ.

In our booth, we are constructing wall and roof systems from our materials, and instead of just having a panel that shows insulation systems or a panel that shows roofing systems, we are building the walls and roof to show those materials from the inside out and the outside in. We want visitors to see how high performing, very green materials can be used to assemble sustainable systems. CertainTeed is unique because we manufacture everything in these constructions but the 2 x 4 framing.

We’ve always had sustainable materials in construction but we were not using them to their maximum potential because we viewed them as individual components.  It’s not about materials alone.  It’s about creating systems and assemblies that not only come from sustainable resources but that perform in a manner which both reduces the energy consumption of a building and extends its life-cycle.  As a manufacturer, we are conducting our research on performance and product interaction. We think about products in terms of systems and want to help design professionals and builders to put together products in a green or sustainable way?

That’s what I like about our booth at Greenbuild: we enable visitors to not only feel the difference between an insulated backed vinyl siding product compared to a fiber cement siding but then show how they perform within an assembly. 

 Another aspect of sustainable systems is the indoor environmental issues like acoustics, ventilation/air quality, and durability.  Depending upon where you live, you want to create systems with appropriate products to meet your maximum goals for R-value, moisture management, ventilation and other variables. Properly designed ceiling products are critical to controlling the acoustics and light reflectance which also contribute to indoor environmental quality, comfort, and visually pleasing aesthetics.

As I have mentioned in previous blogs, retrofitting existing structures to make them more energy efficient is a major challenge.  How do we go back and fix them and make them last longer and perform better?  Dennis Wilde from Gerding Edlen Development Company will share the success they are having with their Sustainable Solutions program at our CertainTeed-sponsored luncheon at Greenbuild. They are mastering the process.  The challenge with green and sustainable building is that everyone is afraid of the learning curve. Everybody wants to be on the leading edge but they don’t want to be on the bleeding edge.  Gerding Edlen has bled the blood and figured out how to do it. They have paid the price in pain and it is a great gift that they are willing to educate the rest of us. 

The room is filling up fast so if you want to attend the luncheon at Greenbuild, email Kristen Harter, Kristen.M.Harter@saint-gobain.com.

Remember: a building that lasts twice as long is twice as green. Stop by and see us at Greenbuild Booth 921!

Lucas Hamilton is Manager, Building Science Applications, for CertainTeed Corporation

Home Improvement on NBC’s Today Show: How Blow-in Insulation can boost a home’s R-value

Lucas Hamilton

Lucas Hamilton

On Wednesday, October 21, home improvement expert, Lou Mandfredini of HouseSmarts™ will appear on NBC’s Today Show during the 8:30 a.m. hour to share some tips with homeowners on how adding insulation to their attics can improve overall energy efficiency and lower energy bills while enabling them to benefit from the federal tax credits. Each week, Lou provides the answers to questions that homeowners have about their homes. Lou is uniquely qualified to do this as a former remodeling contractor and home builder. Lou and his wife are also the owners of an ACE Hardware store in suburban Chicago.
Lou Manfredini

Lou Manfredini

 

During the segment, Lou will discuss the benefits of adding energy efficient insulation to attics and offer hands-on installation tips. Specifically, Lou will demonstrate how the CertainTeed TrueComfort Blow-in Insulation can be used to boost a home’s R-value.  He will also share the best way to add fiberglass batt insulation to an attic floor. If you haven’t seen any of Lou’s previous home improvement segments, you’ll love how he explains projects and materials in ways that everyone can understand. This is one of the qualities that make Lou so effective.

 

Improving the energy efficiency of your home will help to lower your energy costs and your carbon footprint. If your home was built before 1990, you might want to conduct an energy audit, a careful walk-through of your home to identify any air leaks along the baseboard or edge of the flooring, at junctures of the walls and ceilings, or at electrical box openings and plumbing penetrations.

 

Check your local listings for your local NBC channel and tune in to Lou on The Today Show, Wednesday, October 21st at 8:30 a.m.

 

Lucas Hamilton is Manager, Building Science Applications, for CertainTeed Corporation

Energy Awareness: A Life Long Pursuit

yhtp_cm_eam09_lgThe U.S Department of Energy has declared October as Energy Awareness Month to call attention to the need for all of us to adopt new habits to help lower our carbon footprint. The theme for 2009 is A Sustainable Energy Future: We’re Putting all the Pieces Together.

Energy awareness was first observed in the U.S. in 1981 as American Energy Week but was expanded to a month-long observance by the Department of Energy in 1986.  On September 13, 1991, President Bush officially proclaimed October Energy Awareness Month. It’s hard to believe that, in more than 25 years since the initiative began, we haven’t made more headway in energy conservation.  That is why I believe, as I mentioned in my previous Blog Stars Align for Energy Efficiency, that now is, indeed, the time to change our energy consumption habits.

Building Science Engineering has come a long way in understanding and communicating the physical, chemical and biological reactions among a building’s components.  These advances also help to drive the development of products to improve the energy efficiency of new and existing buildings.  Of course, the older the building the less energy efficient it probably is, but many structures can benefit from a mild energy efficiency makeover. 

Here are some tips to determine and improve energy efficiency:

  • Conduct an energy audit.  Locate obvious air leaks by examining gaps along the baseboard or edge of the flooring, at junctures of the walls and ceilings, and at electrical box openings and plumbing penetrations. If cracks are present, caulk and weather strip.
  • Understanding the R-value of fiberglass insulation is important. R-value means resistance to heat flow – the greater the R-value, the greater the insulation power. Visit www.energystar.gov for a map of the recommended R-value insulation levels needed in your region.
  •  Properly controlling moisture will improve the effectiveness of air sealing and insulation efforts. Some insulation systems can provide the added benefit of moisture management in addition to traditional insulation performance. Any insulation that is exposed to significant levels of moisture can decrease R-value performance.
  •  Insulated siding helps improve R-value, up to 30 percent.  Insulated siding can help reduce the heating and cooling costs of a home.
  • Solar reflective roofs can provide long-term protection as well as savings. Cool roofing technology is another simple way to lower energy consumption. This means less work for the air conditioning system, and minimizing the absorption of solar heat through the roof. Solar reflective coatings and solar reflective shingles should be considered for a roofing project.

 The Federal Energy Tax Credit creates a great opportunity for all of us to improve the energy efficiency of our homes.  Let’s not let Energy Awareness Month pass by without taking advantage of savings and efficiency all year long.Lucas Hamilton

Lucas Hamilton is Manager, Building Science Applications for CertainTeed Corporation.