An energy audit can discover lots of heat escaping through a home’s attic and walls. However, a new approach to air sealing and insulation can make a big difference.

To build a better thermal envelope, we need to look at the second law of thermodynamics. This law states that heat flows in one direction, from a warm space to a cold one. For example, warm air inside a home will flow to the cooler air outside during winter months. Fiberglass batt insulation helps prevent this from happening, but there’s a better method for preventing heat loss — one that is easy to install and is within your budget.

The best practice for insulating is to use spray foam insulation to fill the spaces between the framing studs in the walls and attic. Spray foam insulation is nontoxic and typically has a lifetime guarantee. It expands to about 100 times its original volume, so it fills in air gaps unlike standard fiberglass insulation. Over time, as the house expands and contracts, so will the foam insulation. This eliminates cracks and spaces for warm air to escape.

If you’re insulating a small part of a wall or several small spaces, you’re probably better off buying your own tanks of spray foam from a local contractor. However, for areas larger than 200 square feet, such as an attic, you should consider hiring a professional. It’s cheaper for you, and they’ll have the equipment for such a large-scale job.

Here’s how to insulate a large space with spray foam insulation:

• Do a test spray. Remember, this material expands to about 100 times its initial volume, so use it conservatively.
• Spray evenly between the studs and on the backside of the exterior sheathing. Allow it to expand so it fills all the gaps.
• After allowing the foam to form and set, take a handsaw blade and shave away any foam that extends past the studs. The foam needs to be flush so that it won’t be an obstacle when you’re ready to install the drywall.

The most common insulation method is to use fiberglass insulation batts, which are placed between the studs and stapled into place. The drywall is then nailed over it, creating a straight wall. Although this is an acceptable method, it does not create an airtight seal, so heat can escape. The amount of heat that escapes from the average home every day could fill up a blimp. By using the better practice of spray foam insulation in walls and attics, you can create a better air-tight envelope. This gives an advantage over common batt insulation in both efficiency and cost.

BASF announced today (October 5, 2011) that closed-cell spray polyurethane foam products have received hurricane-zone approval from the Miami-Dade County Building and Neighborhood Compliance (BNC) Department. Tests and engineering evaluations of COMFORT FOAM® and SPRAYTITE® (178 series) applied at roofing trusses increased the wind-uplift resistance of a traditional code-approved home roof by more than 200 percent. Spray Polyurethane Foam (SPF) from BASF can enhance wind-uplift resistance of new and existing homes to help prevent roof failure during a hurricane.*

Submission of this test data to the Miami-Dade County BNC office resulted in the first Notice of Acceptance (NOA)** for this application with approval for use in High Velocity Hurricane Zones.

“This new hurricane-zone approval adds high-wind mitigation to an already impressive list of product benefits,” said Michael Sievers, Business Manager, Spray Systems, BASF. Sievers added that this specialty application must be installed by a BASF qualified contractor.

The Miami-Dade County NOA indicates that when BASF spray foam is applied as a three-inch fillet along the truss and roof deck, it glues the roof down to provide a simple and cost-effective means of significantly strengthening the roof against failure during high-wind events. BASF also has Florida Building Code (FBC) product approval (FL #13001) for COMFORT FOAM and SPRAYTITE (178 series) SPF products. Adding a total of three inches of closed-cell spray foam under the roof deck will also give the homeowner energy savings and wind resistance. Reduced homeowner insurance premiums may also be an added financial incentive in some areas of the country.

Homeowners in high-wind areas who want to maximize the benefits of COMFORT FOAM, including: premium-insulating values, improved indoor air quality, reduced energy bills and stronger roofs, are recommended to install a three-inch continuous application to the entire roof deck.

What stands tall after the storm may depend on a strong roof
The National Oceanic and Atmospheric Administration (NOAA) reports that hurricanes account for average insured losses of about 5.2 billion dollars per year in the United States. The majority of these losses were directly caused by severe wind and rain exposure resulting from a failed roof deck, according to a study by Clemson University.

BASF understands the value of providing materials that protect homes during catastrophic weather events including storms, hurricanes and high winds. Particularly vulnerable to these conditions are roofs. According to the Federal Alliance for Safe Homes, if a roof is not properly secured to the rest of a home, the likelihood of structural failure is much greater than if reinforced with hurricane damage mitigation tools.*** This type of application of spray foam glues the roof sheathing to the rafters, giving severe wind and rain no room to enter and weaken a structure.

For more information on the energy and structural benefits of building or retrofitting your home with BASF spray foam insulation, please visit http://www.spf.basf.com.

About BASF Polyurethanes
BASF is the leading supplier of Polyurethane Solutions for systems, specialties and PU basic products. With its global network of 38 polyurethane system houses and its comprehensive product and service portfolio, BASF is the preferred partner of its customers in many industries.

The BASF brand “Polyurethane Solutions” represents over 40 years of experience of the market and technology leadership for Polyurethane Systems.

In the extremely service-oriented business of polyurethane systems and specialties, reliable PU experience and competence are crucial. Through its system house network, BASF provides fast local support, from technical service and sales to production and marketing during the development of customized solutions. With its world-scale plants, BASF secures its leading market position in the production of polyurethane basic products in all regions of the world.

Polyurethanes make life more comfortable, safer and more pleasant while helping to save energy sustainably. They contribute towards improved insulation of buildings and more attractive, lightweight design of cars. Producers of shoes, mattresses and household goods as well as sports equipment use the unique advantages of polyurethanes provided with the knowledge and expertise of the polyurethane experts of BASF world-wide. Further information is available on the internet at http://www.polyurethanes.basf.com.

When you buy a new house, before it’s built, you get to choose from the variety of styles and floor plans the builder offers, as well as options and upgrades on details and finishes. Depending on the builder, sometimes the options and choices of upgrades are very limited. Most times, those options are limited to finishes. Rarely do they offer green upgrades, or upgrades on what matters most: what’s behind the walls.

A lot of builders and building companies have model homes, or even a design centre you can visit to help you decide on the finishes and upgrades you might want to add. What’s on display is always finishes. It’s never the insulation, the drywall or tile underlayment. You’ll never see air purifiers on display or added as an extra appliance.

Energy Star appliances are standard now with new homes, and they are built to minimum code standards with regard to construction, building envelope, insulation.

But what about green upgrades?

Some leading green builders offer features such as solar rooftop photovoltaic (PV) and solar hot-water pre-heating rough-ins for those who want that option. And lots are coming on board with low/no VOC paints, and maybe some bamboo flooring. But that’s about it, I’m sad to say.

That’s all driven by consumer demand. Builders will build what sells, so it’s up to you to demand upgrades that will really increase the value of your home.

What do homebuyers think is important when they invest in their new homes?

Everyone is concerned about indoor air quality, and the effects of mould and allergens on their families’ health. But how many people are even aware of the upgrades they can have that will improve that indoor air quality? The type of insulation you choose, the type of cabinets and flooring, all contribute to the indoor air quality. What about adding an air-purifying system or premium HEPA filtration to your HVAC?

Some people will advise you to choose your upgrades based on future resale of your home. That’s fine, but who’s to say a brushed nickel faucet will still be fashionable when your home goes on the market? Will cherry cabinets be in, or will painted wood? Is your money better spent on a granite countertop or on a properly insulated basement and attic?

A finished basement is a popular one. But for me, this is one of the real traps of a “builder upgrade.” Guaranteed: If you opt for this upgrade, you will have a basement finished to minimum code. That’s all that’s required. And that will be a complete waste of your money — in either a short time or a slightly longer time — when you need to tear everything out because it’s tainted with mould.

Conventional wisdom says that spending your upgrade money on kitchen and bathrooms will repay you. But I say that every penny you invest in an upgrade that improves your home’s efficiency will repay you, too.

I say, when your budget is limited — and whose isn’t? — spend your upgrade money on the places you can’t get to later: behind the walls. You can always upgrade a standard finish to something pricier later, if you want to. But you can’t easily change your insulation or the underlayment beneath your tiles or replace your standard drywall with mould-resistant.

The consumer decisions always seem to be: Do you want the premium kitchen cabinets or the standard? Do you want a granite countertop or laminate? What kind of tile do you want in the bathroom?

People spend hours discussing choices of light fixtures, door handles, cabinet hardware, plumbing fixtures, paint colour, crown moulding and style of baseboards. Who cares? Seriously.

What about the level of insulation — code or above code? What kind of insulation — blown-in cellulose, batt, or spray foam? How good are the windows?Are they high-performance? BluWood or standard? Mould-resistant drywall or standard?

Can you choose sustainably sourced hardwood for your flooring?

Ask the questions. Make the right choices on your upgrades.

The article highlights the benefits of using closed-cell spray polyurethane foam (ccSPF), also known as medium-density spray foam, in residential construction.  ccSPF can be used as cavity insulation and as an exterior wall and roof material. The material has applications in all climate zones.

Among the numerous benefits offered by ccSPF, the material’s water resistance can be an invaluable asset in the face of the severe weather conditions common to coastal regions. In fact, “Closed-cell spray foam has negligible water permeability, minimal water absorption, and excellent adhesion allowing it to act as a secondary rainwater barrier to limit damage when primary roof assembly rainwater-control membranes leak,” states Christopher J. Schumacher, a principal with Building Science Consulting, Westford, Massachusetts.

Everywhere there are joints and cracks, the spray foam seals and prevents the entry of water. In cases where the primary roof does leak, the ccSPF application can keep water from spreading through to the interior finishes.

And for low-slope roofing, ccSPF, by itself, can actually perform as a primary water barrier due to its high adhesion and closed-cell characteristics. It keeps away mold and mildew and is the only FEMA-approved cavity insulation for homes built in flood zones.  Furthermore, after it is exposed to water, it demonstrates rapid drying capability.

The high-performance insulating material, closed-cell SPF, strengthens the same walls they insulate. Closed-cell SPF is stiffer and stronger than other insulations. For that reason, ccSPF can strengthen frame walls by a factor of two to three times when applied inside the wall cavities.

An additional area where ccSPF has well proven its worth includes withstanding wind uplift. Considering the fact that uplift of the roof deck is, after window and glazing damage, the most common form of hurricane damage, this can be key.  Testing shows that wind uplift performance can increase by two to three times with spray foam insulation.

Beyond water resistance and wind uplift, additional ccSPF properties include thermal insulation and airflow control.  Closed-cell spray foam acts as an air barrier (at 1 in. or 25 mm minimum thickness) and vapor retarder (at 2 in. or 50 mm minimum thickness) and therefore does not need an additional vapor retarder in cold climates. And because ccSPF is air impermeable, it adheres well to construction surfaces and expands to fill voids, thereby creating an air seal.

With ccSPF, all these problems are eliminated. Industry groups like the Spray Polyurethane Foam Alliance (SPFA) and the Spray Polyurethane Foam Division of the Society of the Plastics Industry (SPI) list a number of additional benefits:

• Energy transfer through ductwork is no longer lost to the exterior.
• Water pipes are better protected from freezing.
• Airtightness requirements for the ceiling plane are reduced or eliminated.
• Renovation and rewiring involve no disturbance to the insulation layer.
• Attic storage space

Homeowners can quickly search for spray foam contractors in their state, through our convenient search engine.  Search results can rapidly be scanned for areas of special interest with the certification icons.  Each potential contractor can be contacted directly for a custom estimate and/or reference checks.

Homeowners looking to save money on their long-term energy bills will find the Spray Foam Homes site extremely useful with tips and best practices for reducing energy consumption.  The combination of spray foam insulation and practical advice will save homeowners tremendous amounts of money year after year.

Our mission is to provide homeowners, as well as builders, GC’s, architects and all other energy-conscious individuals with the most current news and information on spray polyurethane foam technology.

We invite your commentary, thoughts, and suggestions for topics.  In fact, if you’d like to submit an article for publication on the Spray Foam Homes site(s), please email it to us.  All submissions are welcome!

Expanding spray-in-place foam insulation products such as those based on a polyurethane formulation have several beneficial aspects over other forms of insulation. Spray foam insulation currently costs more than alternative insulation products, but this additional upfront cost can be overcome when the other benefits of spray foam are utilized and realized. These aspects include benefits associated with increased structural/strength properties, enhanced thermal insulation capabilities, and reduced air infiltration properties.

Structural benefits: Clemson University has been researching the use of spray foam as an enhanced attachment system for roofing. This research centers on how to retrofit or construct buildings to be more resistant to hurricane and other high wind events. Clemson’s research shows that spray foam can significantly improve the attachment of roof sheathing to trusses and rafters, similar to the way construction adhesives help bond a floor system together. In a retrofit case, foam can be sprayed on one or both sides of the sheathing/rafter intersection from inside the finished roof. In new construction, spray foam can be applied to the entire roof system. The spray foam makes a significantly stronger roof than either nails or screws alone. More information on this research is available from Clemson University’s Civil Engineering Department, or the 113 Calhoun St Project in Charleston, SC.

Thermal and air benefits: A second aspect of spray foam is the enhanced thermal insulation characteristics. The stated R-value, or thermal resistance value, of insulation is measured under laboratory conditions. Real-life in-use R-values are quite different. An R-13 rated insulation batt installed improperly may only provide R-9. Whole wall Rvalues may be even less because of voids, wood, headers, etc. in the wall. Spray foam can provide a higher whole-wall R-value because of its ability to better fill wall cavities around electrical, plumbing, and other obstructions within the wall. The Oak Ridge National Lab has tested several whole-wall R-values for various wall/insulation combinations. Some of their results have been published in publications such as Energy Design Update, and should be available on their web site soon.

The R-value of an insulation system also depends upon the lack of air movement through the insulation. Most insulation products use entrapped air as a barrier to heat transfer. Therefore, to get a high R-value, air cannot move within or through the insulation.

In a whole-house situation, part of the energy use is in infiltration air. Air flow retarder products such as house wraps were developed to reduce the amount of infiltration air. These air barriers help reduce infiltration as well as air movement through the insulation.

Typical loose fill or batt insulation works well if installed correctly, and if installed in conjunction with an air barrier. Good installation is difficult to do, however. The insulation is often packed too tight or too loose, cut too short or too long, gapped around plumbing and wiring, or left out because of access problems.

Spray foams claim a couple benefits. First, they fill gaps and voids better. Second, they perform well as air flow retarders. The result is a higher in-the-wall R-value. Infiltration is also reduced, so that component of a building’s energy use is reduced. Both of these benefits result in raising the “effective” R-value of spray foam when compared to typically installed loose fill or batt insulation.

Spray foam products must still be sprayed correctly, and dense-pack blown cellulose can make some of the same claims. Spray foam is also self-supporting, which enables its use on the underside of roofs and floors.

Roof Benefits: Insulating the underside of a roof rather than a ceiling creates many other benefits as well. Historically, we ventilated roofs in an attempt to prevent moisture problems and reduce heat build-up.

Current research shows that much of the moisture in attics comes from damp basements or crawl spaces, as well as from the living space. Research also shows that if we address crawl space, basement, attic and living space moisture, we do not need to ventilate an attic. In fact, by ventilating an attic, we can often make a moisture problem worse.

Attic moisture problems are a result of moisture condensing on cold roof surfaces. Adding more vents causes the attic to be cooler, especially at night, which causes more condensation to form on the underside of the cold roof. Cutting a hole in the roof causes a bigger hole in the top of our “chimney”, which makes the “chimney” draw better, pulling even more moisture upward. I have not seen any attic moisture problems solved by adding attic ventilation, with the exception of ice damming. (Ice damming is a “warm” attic phenomenon, and can better be addressed by reducing the amount of heat leaking into the attic.) Unfortunately, the building codes haven’t kept up.

Ventilation to reduce summer heat build up in an attic has also been challenged recently by research done at the Florida Solar Research Center and the Building Research Council in Illinois. Much of the heat in an attic is from radiant heat transfer. The hot sheathing radiates heat to the ceiling or other objects in the attic. To cool an attic, outside air is vented through attic or insulation is added to the ceiling to prevent the attic heat from warming the living space. Research has shown that the ventilation rate would have to be quite large to make much difference in an attic temperature. In the summer, the best you could possibly achieve was outside temperature. With a very large fan using lots of energy, you might get close to outside temperatures. In winter, this would result in a colder attic as well.

Ceilings are usually insulated because of the ease of piling up cheap insulation. Recessed lights, outside walls, sloped or tray ceilings and knee walls all create a non-uniform thermal “cap” on the building and result in voids in the insulation. The real-life R-value of an insulated ceiling is very often less than the claimed R-value.

Ducts are often located in the attic, which exposes the coolest/warmest air in the house to the hottest/coldest environment in the house (depending upon the season). This does not create a very energy efficient situation. As much as 10% of the heat or AC can be lost by placing ducts in an unconditioned attic.

From an energy standpoint, ducts and air handlers should be located within the conditioned space. This reduces heat transfer to the outside, and reduces some concern of duct leakage. Recently, building researchers proposed making crawl spaces into unvented, conditioned plenums, which is now accepted by code. More recently, building researchers proposed making attics into conditioned space by eliminating ventilation and insulating the underside of the roof rather than the ceiling. As a building researcher, I fully support both concepts.

A roof system insulated with spray foam reduces energy several ways. Energy loss from ducts located in the attic is essentially eliminated. The top of the building is much tighter resulting in less infiltration and exfiltration, so excess moisture isn’t pulled into the attic. Infiltration through the ceiling is also reduced. In addition, the attic temperature is lower, which further reduces energy loads.

In a standard insulation system, ceiling insulation reduces the transfer of heat from the attic to the living space (in the summer). Attic temperatures can often approach 140F during the day. Most of this heat enters the attic space through a multi-step process. First, solar energy warms the shingles and sheathing. The hot sheathing then transfers heat to the rest of the attic through conduction, convection and radiant heat transfer. The 140F temperature of the underside roof surface drives the heat transfer process

By insulating the roof surface with spray foam, the surface temperature exposed to the attic (the temperature driving the heat transfer) is reduced by as much as 40F. Both conduction and convection heat transfer are proportional to a temperature difference, so that heat transfer will be reduced proportional to a drop in surface temperature. Radiant heat transfer, though, is proportional the 4th power of the temperature difference. The reduction in radiant heat transfer resulting from an insulated roof can easily exceed conduction and convection reductions.

The benefits of including the attic in the insulated space are:

• Duct leakage and heat loss/gain from ducts is much less of an issue.
• Air sealing is easier in the roof that in the ceiling.
• Dust and loose insulation are less likely to migrate down to the living space.
• Tests show energy costs are lower when the attic is sealed.

Further information is available from ASHRAE (8700-527-4723) in a publication titled “Vented and Sealed Attics in Hot Climates”.

Crawl Spaces Benefits: Batt insulation is usually installed between the floor joists over a crawl space foundation. Problems associated with this installation technique include incomplete thermal barriers from obstructions such as wiring and plumbing, ductwork, and narrow or wide joist spacing. Batts are often compressed during installation due to the use of wire insulation hangers. Open web floor trusses create additional problems in that the open webs create pathways for air to move around the batts. During the summer, warm humid air can flow around the batts and create condensation, mold and decay problems in the floor system. In my opinion, open web floor trusses are impossible to adequately insulate with batts.

Spray foam circumvents floor insulation problems through its ability to completely fill voids and open spaces. Areas around wiring and plumbing as well as open webs of floor trusses can be completely filled, resulting in a complete, essentially uniform thermal barrier on the floor. Spray foam will also create an effective air flow retarder layer on the floor, which will reduce the house air by crawl space air.

In my opinion, spray foam insulation is a superior insulation product that overcomes several disadvantages of other insulation products. Spray foam can provide a more uniform, consistent thermal barrier as well as provide air flow retarder functions. To best obtain spray foam’s potential benefits, and overcome it’s higher initial costs, spray foam should be used in a systems approach to creating a better building. In a roof application, spray foam will increase the structure’s ability to handle high winds as well as bring the attic into the conditioned space. A roof application of spray foam will reduce infiltration and reduce ceiling heat transfer and duct losses. Wall and floor applications will also create better thermal and air barriers, and make better use of engineered products. Spray foam insulation can result in less conductive, convective and radiant heat transfer, lower infiltration rates, less duct losses, a more structurally sound building and can result in significantly smaller-sized heating and cooling systems and better comfort levels for the occupants.

With foamed-in-place insulation, it is relatively easy (though not inexpensive) to fill wall and ceiling cavities completely. Closed-cell spray foam provides a higher R-value per inch (6.5) than less expensive insulation types like cellulose and fiberglass (3.5 to 3.7).

Most spray polyurethane foam is called “two-component” foam. Two ingredients—conventionally called “A” and “B” components—are mixed on site using special equipment mounted in a trailer or truck. Heated hoses convey the components to a mixing gun that sprays the chemicals on the surfaces to be insulated.

A chemical reaction begins as soon as the chemicals are mixed. The liquid mixture foams, expands, and eventually hardens.

Choose a conscientious installer

Most jobs are for pros
Spray polyurethane foam is usually installed by a spray-foam contractor equipped with a truck or trailer to carry the necessary chemicals and spray equipment.

For smaller jobs, builders can purchase disposable tanks of two-component polyurethane foam. These tanks are sold in various sizes, and range in cost from about $200 to $500. For very small jobs, small aerosol cans of one-component (moisture-cured) polyurethane foam can be purchased at most building-supply stores for about $5 a can.

Experience matters
Although spray polyurethane foam has many advantages over other types of insulation, spray foam installation isn’t foolproof. Some builders have reported problems with sloppy foam insulation. For example, some installers have been known to begin spraying before the chemical components are up to temperature, which can affect component mixing and foam performance. When components are poorly mixed, or mixed in the wrong ratio or at the wrong temperature, cured foam has been known to shrink away from rafters or studs, leaving cracks. Some installers rush through their spraying, resulting in voids.

As with any type of insulation—whether fiberglass batts, cellulose, or spray foam—it’s important to choose an installer with a good reputation; to monitor the installer’s work; and to verify that the insulation work meets expectations before making the final payment on the job.  Since spray foam is messy, the best bet is to get everybody who’s not part of the foam crew out of the house. Have some helpers nearby to watch the installation, and be ready with drop cloths, tape, and caulk to stop or catch any drips that find their way to the exterior of the house.

OPEN-CELL FOAM

Half-pound foam, also known as open-cell foam, has a density of about 0.5 lb. per cubic foot and an R-value of 3.5 or 3.6 per inch.

Open-cell foam is relatively vapor-permeable. Three inches of open-cell foam have a permeance of 16 perms. When installed in a cold climate, the interior face of open-cell SPF should be covered with a vapor retarder (for example, vapor-retarding paint).

Some of the low-density foams are made in part from bio-based raw materials—for example, soybean oils—in place of a portion of the petrochemicals. Open-cell foams use water or carbon dioxide as the blowing agent.

Compared with closed-cell polyurethane, open-cell products use significantly less material, making them attractive from a resource-use standpoint. However, open-cell foams have a lower R-value per inch than closed-cell foams.

Open-cell foam is vapor permeable. When used to create a cathedralized attic in a cold climate, open-cell foam should always include a vapor retarder. This can be accomplished by spraying the cured foam with vapor-retarding paint.

CLOSED-CELL FOAM

Two-pound foam, also known as closed-cell foam, has a density of about 2 lb. per cubic foot and an R-value of 6 to 6.5 per inch. Two-pound foam is significantly more expensive than half-pound foam.

Closed-cell foam is a vapor retarder. Two and a half inches of closed-cell foam have a permeance of 0.8 perm.

The blowing agents in most types of closed-cell spray polyurethane foam are hydrofluorocarbons (HFCs) with a high global warming potential. Because the global warming potential of these damaging blowing agents is 1,430 times more potent than carbon dioxide, many green builders avoid the use of closed-cell spray foam. For more information, see Calculating the Global Warming Impact of Insulation.

While these tips are short-term or quick-fix suggestions, one of the things people are discussing is long-term solutions to stay cool and reduce energy consumption.  Spray foam insulation is specifically designed for this application. Homes that contain spray foam are far superior in their ability to tighten the thermal envelope. If you have air conditioning, you can save electricity by sealing everything that separates the inside of your home from the outside. Spray foam insulation is the best air sealant. Check the caulking around windows and weather-stripping around doors. Storm doors and storm windows actually can help keep cool air in the home so your air conditioner doesn’t have to work as hard.

With proper planning, you can be completely prepared for next summer’s heat wave.  Reduce your energy bills while keeping your home cooled to you comfort level… these are just a few of the many benefits of spray foam insulation.