| When can spray foam be installed? |
| Spray foam insulation is professionally installed at the same point in the construction cycle as other types of insulation. That is, it should be installed after the rough plumbing, electrical wiring, and heating and air conditioning ducts have been installed, but before the interior walls are completed in new construction. In some cases spray foam also can be applied in other buildings or structures, to the inside of roofs and under floors after construction has been completed. |
| How does spray foam work? |
| A two-part mixture is applied by trained professionals to the surface to be insulated. The spray mixture expands rapidly to fill all cracks and voids, completely and permanently adhering to wood, masonry, metal, concrete, and most other construction materials. |
| Which is better, closed or open cell? |
| Both systems offer significant advantages over fiber-based insulations: ability to air seal; ability to fill cracks and conform to odd shaped cavities; and ability to hold their shape over time and under adverse conditions. But only closed-cell foam has the thermal insulation value (R-value) to bring your building up to Energy Star® standards with only one-half the thickness required for fiber insulations. In addition, closed-cell foam products increases the strength of your wall system (it's approximately doubled) and increase the water resistance of your building's exterior. |
| How does closed-cell spray foam provide moisture protection, yet still breathe? |
| Unlike cellulose and fiberglass materials, closed-cell foam is impervious to water penetration and wicking. Yet, like Gortex® fabric, the closed-cell structure allows the diffusion of water vapor (high energy particles) to allow your building's envelope to "breathe". Liquid water has much larger particles and is unable to pass into or through a closed-cell foam barrier. |
| What's a "thermal barrier" and when is it needed? |
| A thermal barrier is a covering between the interior of a building and the surface of the spray polyurethane insulation which will protect it for at least 15 minutes in the event of a fire. ½-inch gypsum wall board, such as Sheetrock®, is an approved 15-minute thermal barrier.
Building codes require the installation of a thermal barrier between foam plastics (such as spray polyurethane insulation) and any occupied space. Exceptions apply in some cases; review local codes and/or confer with your local building code officials.
The building code provides for an exception to the thermal barrier requirement in attics and crawl spaces where entry is made only for the service of utilities. In such cases, the spray polyurethane insulation must be protected from ignition. NCFI offers Aldocoat 757, a spray-on ignition barrier coating for these areas.
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| How does the NCFI spray polyurethane insulation seal my building? |
| NCFI spray polyurethane insulation is sprayed on as a liquid which reacts and expands in place. This expansion action also seals all of the cracks and crevasses in your wall's exterior sheathing. The result is that air can no longer slip in: your building will be less drafty and more comfortable.
Air leakage can also introduce moisture into the wall cavity, resulting in wet insulation and mold and mildew. With the sealing effects of NCFI spray polyurethane insulation; this will not be a concern.
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| Won't sealing my building lead to indoor air quality problems? |
| Your building does need to be ventilated. Most design professionals will advise you to seal the structure as tight as possible and provide the necessary ventilation through the heating and air conditioning system. Many systems employ an "air exchanger" which is designed to pre-condition (either warm or cool) the incoming outside air with the outgoing exhaust air. In this manner, you can build an extremely energy efficient exterior shell using spray polyurethane foam while still providing controlled and energy efficient ventilation. |
| Is spray polyurethane insulation code approved? |
| Yes. Building codes provide for the use of spray polyurethane insulation in the Foam Plastic section. This section of the code also describes the use of thermal barriers. |
| At what point in the construction should spray polyurethane insulation be applied? |
| Normally spray polyurethane insulation is installed at the same point in the construction cycle as other types of insulation. That is, it should be installed after the rough plumbing, electrical wiring, and heating and air conditioning ducts have been installed. If you decide to seal the entire exterior shell with spray polyurethane, spray insulation may need to be applied in some areas before the ductwork is installed. |
| Can I use NCFI spray polyurethane to insulate an existing building? |
| Spray polyurethane insulation is used primarily to insulate new buildings or structures. This is because spray polyurethane must be applied to an open cavity. When spray polyurethane is injected into a closed wall cavity, the pressure of the expanding insulation may damage the wall. Consider insulating an existing building with spray polyurethane when you’re replacing the exterior siding or doing other major remodeling. |
| Will I save money if I insulate with NCFI spray polyurethane insulation? |
| Yes! The installed cost of spray polyurethane is somewhat higher than glass fiber batts or blown-in cellulose. However, the higher initial cost is partially offset because you can leave off the wrap and your heating and air conditioning equipment can be smaller.
You will save in your heating fuel and electric bills. Studies suggest that buildings insulated with spray polyurethane use 20 to 40 percent less energy than those insulated with conventional insulation. Your savings may be greater or less depending on your structure's appliances, building site, number and size of windows, etc. |
| Will spray polyurethane insulation lose R-value over time? |
Open cell foams trap air to create the R value and therefore stabilize very quickly after the application, resulting in R values per inch of thickness the same as fiber based insulation, which also attempt to trap air to provide its R value.
Closed cell systems utilize a blowing agent that creates an inert gas of complex molecules that are highly resistant to heat flow. The foam is formed by the chemical reaction of two hot liquids and this reaction also creates more heat in the process. This hot gas, in the 160°F range, is trapped in the foam matrix during the chemical reaction as the cell walls form the micro-cellular membrane. As this gas cools back to room temperature, the cell walls remain fixed, setting up a lower air pressure inside the cell than the air in the atmosphere.
While the large inert gas molecules are trapped inside the cells, the much small molecules of elements in the air can diffuse into the cells. Due to the lower pressure inside the cells, the smaller molecules diffuse into the cells over time, stabilizing the pressure, which also reduces the heat transfer resistance of the foam; or lowers the R value. The R value stabilizes and remains at that level unless the foam is cut or damaged. This reduction is typically 2 to 4 percent, so the R value reduction will be a couple of tenths, something like R value of 6.7 measured just after spraying will stabilize at 6.4 or so. The stabilized R value is measured by an industry, building code approved ASTM protocol. All manufacturers of closed cell foams are required to "age" the foam and measure and report the stabilized R value using these approved ASTM test methods.
When first installed, spray polyurethane foam’s R-value is about 10 for a one-inch thickness. Over time, the R-value drops to between 6.5 and 7.0 (one inch) and stabilizes at that value. The time it takes to reach an R-value of 6.5 to 7.0 depends on a variety of factors, including total foam thickness. We report a six-month aged R-value. Many industry studies indicate that a one-inch thick sample of foam will stabilize after six months and maintain that approximate R-value for decades.
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| Can spray polyurethane insulation be applied directly to electrical wiring? What about installed electrical devices like recessed lights? |
| Spray polyurethane can be applied directly to electrical wiring. Recessed lights or other fixtures may require a certain amount of air circulation around them for cooling purposes. In these cases, a box can be build around the fixture with gypsum wall board; then spray foam can be sprayed directly to the outside of the box. |
| Will spray polyurethane insulation deteriorate over time? |
| Ultra-violet light (sunlight) will cause the foam to degrade over time, so polyurethanes applied to surfaces that will be subjected to sunlight (an outdoor tank) will need to be covered or coated with a UV barrier coating. For interior applications as in your house walls, we are not aware of anything that will degrade the foam. We've looked at 20-year old spray foam projects when remodeling required the walls be opened, and have not observed any signs of deterioration. We expect the NCFI spray polyurethane insulation system to insulate and seal your building for the life of the structure. |
| How long has spray polyurethane been used to insulate houses? |
| Spray polyurethane foam was commercially developed in the United States in the mid-1960's. Buildings have been insulated with spray foam since that time. NCFI is aware of houses insulated with our spray foams in the early 1970's. |
| Will spray polyurethane insulation absorb or entrap moisture? |
| Most moisture problems in houses are due to moisture entry from air leakage. Because spray polyurethane insulation provides such an excellent air barrier, this source of moisture is virtually eliminated. Other potential sources of moisture can be excluded with proper construction techniques and materials. Unusual building use (such as freezers or swimming pool buildings) may require a vapor retarder. Contact us regarding your specific situation if you have any questions. |
| Does spray polyurethane foam contain formaldehyde? |
| No. |
| What equipment do I need to apply spray polyurethane insulation? |
| Required equipment elements include a plural component proportioner pump with heaters, dual high pressure heated hoses, high pressure mixing and spray gun, and feed pumps and hoses. In addition, an air compressor and electrical generator may be needed. |
| Can a building owner apply spray polyurethane insulation? |
| Not practically. Spray polyurethane application requires complex equipment and a skilled installer. |
| Will spray polyurethane insulation strengthen my structure's walls? |
| Yes! NCFI InsulStar® closed cell foam is strong and structural. Your walls will be more resistant to winds and you'll notice less creaking and shaking when doors are slammed. NCFI's Sealite® open cell foam is lighter density and not as strong as InsulStar® but will still seal your walls and add strength to your home. See our report on Wall Strength for more information. |
| How long does it take to install spray polyurethane insulation?
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| Quite quickly. A single-story building can be fully insulated with spray polyurethane in a day or less. Large buildings with complex design features could take longer. |
| Insulation General |
| How can I repair blisters? |
| 1. Before repairing blisters (see step 2), thoroughly inspect the roof system to determine the source of the blisters. If it appears that it is a surface phenomenon, then go to step 2. If the blisters go down to the surface, there may be a moisture issue with the roof system.
2. Remove the blisters by scraping or power washing to the point where you have a sound surface for re-coating. Allow surface to dry completely, and then apply the correct product for the job.
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| Why does the roof coating look like it is wrinkling? |
| Wrinkling is the aftermath of significant blistering of the coating. Sometimes, blisters will go away, but if the blistering is bad enough, the coating has been stretched too far and the blisters cannot recover. The repair suggestions for wrinkling are the same as for blistering.
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| Why is the roof coating flaking or peeling? |
| Flaking or peeling is due to a loss of adhesion. This could have been caused by blistering or simply because the coating was not designed for the surface. The repair suggestions for flaking and peeling are the same as for blistering.
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| It looks like the roof coating had bubbles when it was wet, but now that it is dry, the bubbles are broken, leaving small dimpled spots on the coating surface. What causes this?
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| These defects are caused by foam that is trapped in the coating while it is wet. A properly formulated coating may still have bubbles in it, but these bubbles should break and flow out smoothly so that when the coating dried, the surface is smooth. However, if the bubbles do not break quickly enough and the coating begins to dry, then they will not flow out and you'll see these defects on the surface. In most cases, these defects will not affect the ultimate performance of the coating; they are usually just aesthetic nuisances.
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| What causes mildew or algae? |
| Mildew and algae can grow on practically any surface. The more a surface is cool and damp, the more prone it will be to mildew or algae growth. In general, climates like the southeast and south-central United States are more prone to mildew and algae than climates in the southwest. A quality coating is designed to resist the growth of mildew or algae on its surface. The length of time a coating will resist mildew or algae varies, but should be at least a few years.
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| How Can I remove mildew or algae? |
| Mildew or algae can be easily removed by power washing the surface with a mild bleach solution (one part bleach maximum, three parts water is more than sufficient).
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| Why does the roof coating have roller or stipple marks? |
| Roller or stipple marks are unintentionally left behind by the painter's roller. In general, the longer the nap of the roller covers, the more marks you will see. Roller marks can be more pronounced if the applicator is pushing too hard on the roller or using a low-quality roller cover. These roller marks will not affect the ultimate performance of the roof coating significantly. As an aside, one of the benefits of spray-applying roof coating is that you will not get these roller marks from the spray application.
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| Why is the white elastomeric roof coating turning yellow? |
| If the underlying substrate is asphaltic, especially a fresh asphaltic substrate. The yellowing is most likely due to asphalt bleed, which is simply low molecular weight asphaltenes leaching up through the coating. This discoloration will not hurt the performance of the coating. It is an unsightly aesthetic issue, but in most cases, the yellow color will bleach out and disappear over a few months.
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| What is the white powdery material forming on the roof coating? |
| During the natural weathering process of a coating, the coating will eventually erode. A good quality coating will not start eroding for several years, but when it does, the erosion process releases some of the pigments in the coating. These pigments are white, so they appear on the surface as a chalk-like powder. This mode of erosion is typically called chalking. A little bit of chalking is normal and is part of the natural erosion process. However, excessive chalking is normal is not good and is a sign that the coating is degrading too quickly.
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| Some damage occurred to the roof such that the polyurethane foam underneath is now exposed. What can I do? |
| Fortunately, one of the advantages to a roof system that has polyurethane foam as the underlayment is the ease of repair. In general, for damage less than ¾-inch diameter and ¼-inch deep, the area can be repaired with caulk alone or caulk and coating. For damage bigger than this, it may be prudent to remove damaged foam, and use both caulk and coating, or for multiple damage points (about 20 or more), consider scarifying the foam surface, re-foaming, and then re-coating. |
| Why is the elastomeric roof coating dirty? |
| Over a long period of time, it is not unusual that some dirt can accumulate on the surface of a coating. However, significant dirt early in the life of a coating is not desirable. When the surface of a roof coating is very dirty (hopefully after many years of service), the dirt can be removed by power washing with a mild soap and water cleaning solution, followed by a power wash with just water. This can be done as part of a maintenance program to keep a coating looking fresh; or, if the coating has been in service for many years, it could be time to apply another fresh coating of high-quality elastomeric roof coating.
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