Spray Foam Insulation

Spray Foam Insulation Contractors, Missoula, Montana

Energetechs is Missoula’s most responsible insulation installer. We are not your typical “one size fits all” contractor. We take the time to figure out which solution works best for the home, the homeowner, and the environment in each particular situation. To this end we offer a number of different insulation technologies. One of these is spray-in (sometimes called blown-in) polyurethane foam insulation. This high-performance insulation is made by mixing two separate liquid chemicals and using special equipment pressurized with nitrogen to spray the foam insulation into cavities and exterior surfaces.

Advantages of Spray Foam

High R-value Insulation

Spray Foam insulation has numerous advantages over conventional fiberglass or cellulose insulation. Firstly, it has significantly higher R-value per inch. R-value is a measure of Resistance to Heat Flow. The higher the R-value the better a material resists heat flow so the better it is at insulating a home. Fiberglass and cellulose have R-values in the range of R3 – R4 per inch whereas high-density spray foam has R-values around R6 per inch (about twice as good). This means that in a typical 2×6 framed wall, you can get about R19 using fiberglass or cellulose and about R33 using spray foam.

Air-sealing properties of spray foam

High-density Spray Foam insulation also has the advantage of being both an insulating material AND an air-barrier. This is very important to creating an effective “Thermal Boundary”. To create an effective Thermal Boundary it is important to understand that insulation by itself does not stop air movement. An excellent insulation job requires excellent air-sealing in order to be effective. Insulation without good air-sealing is like being out in a blizzard wrapped in a thick blanket that has a lot of holes in it. It won’t keep you warm. On the other hand, air-sealing without good insulation is like being out in a blizzard dressed only in a tightly sealed garbage bag. It won’t keep you warm either. As mentioned above, high-density spray foam provides both of these whereas fiberglass and cellulose do not.

Sound Insulation

Because of its excellent air sealing properties, spray foam insulation is also excellent for sound-proofing building assemblies. As with any form of cavity insulation, it won’t stop sound that is carried through the actual structure of a building (studs, joists, beams, etc) but spray foam does an excellent job of stopping air-born sound. One of the often-overlooked advantages of an energy efficient building envelope is the fact that a home that is well insulated and air sealed and has really good windows will be much, much quieter inside than your average home. You will hardly even notice noise from busy streets, neighboring college kids, or planes flying overhead.

Vapor-barrier insulation

Finally, high-density spray foam insulation also provides a vapor barrier that can prevent moisture vapor from reaching a dew point within building assemblies and condensing to liquid water inside walls, roofs, and other hidden places in your home. Once again, fiberglass and cellulose by themselves to not stop moisture moving through building assemblies and so often require the addition of a separate vapor barrier to prevent water damage, rot, mold, and condensation inside your home.

Disadvantages of Spray Foam Insulation

High-embodied energy insulation

Of all of the available insulation materials polyurethane spray foam has one of the highest “embodied energy” components. Embodied energy is the amount of energy required to produce a building material and get it to where you need it. Cellulose insulation has by far the lowest embodied energy of the available insulation materials which one of the reasons why, at Energetechs, we try to use it wherever possible. Another reason is that cellulose insulation is made almost entirely of natural fibers from recycled paper. Spray foam insulation is neither natural, recycled, or low in embodied energy.

Insulation from petroleum by-products

The raw materials that make up polyurethane spray foam insulation come from by-products of the petroleum industry and therefore have a serious environmental impact.

Off-gassing and fire

Both the manufacture and installation of spray foam produce significant quantities of Volatile Organic Compounds and other chemical gases that can have significant environmental effects. After application the foam ceases off-gassing quite quickly so is not a hazard to the occupants of a home insulated with spray foam unless there is a fire. When spray foam burns it produces a lot of toxic smoke which can be potentially fatal to people caught inside a burning home with spray foam insulation. For this reason it is required by code that spray foam in certain applications in homes has to be covered with an “ignition barrier”. This won’t stop it from burning but will, hopefully give the occupants time to escape before the foam starts to give off toxic smoke.

Moisture trapping potential

However this property of spray foam insulation can also create potentially hazardous situations in which the foam actually traps moisture inside building assemblies. It is vital that your insulation contractor understand the building science behind these situations so that they can be avoided. Moisture vapor from either the outside or the inside of a home can readily be trapped inside building assemblies under certain conditions if there is a vapor barrier material like spray foam insulation incorrectly installed or in the wrong place.

Ventilation and the “too-tight” house

From the energy efficiency point of view there is no such thing as a “too-tight” house. However, from the health and safety point of view, there can certainly be an under-ventilated house. Because of it’s excellent air-sealing properties, the liberal use of high-density spray foam in a home creates a situation where balanced mechanical ventilation (preferably heat recovery ventilation) becomes essential to ensure good indoor air quality and a constant supply of fresh air. Another potential hazard when air-sealing a home is the increased potential for backdrafting atmospherically combusted furnaces, boilers, and water heaters. The tighter the home, the easier it is to cause the combustion gases from these appliances to get sucked back down the flu pipe and into the home. The best solution to this is the installation of sealed combustion equipment.

When to use Spray Foam Insulation

Because of the potential hazards and environmental effects we are very careful about when we use spray foam insulation. In every different situation we weigh the benefits of exceptional R-value, air sealing, and moisture vapor control with the potential for indoor air quality, safety, and environmental problems before we decide to use spray foam. Typically we will only use spray foam if there is no practical and cost-effective way to properly insulate and air seal a building assembly using cellulose insulation. Often this includes insulating cathedral (sloped) or flat ceilings, rim joists, and shallow assemblies where there is not enough depth to gain sufficient R-value using cellulose.

Insulation using the “house-as-a-system” approach

Hopefully you have gathered from the information above that it is essential that your insulation contractor understand the complex relationships between insulation, air sealing, ventilation, heating systems, moisture movement, and environmental effects. This is why the team at Energetechs is constantly studying building science and is devoted to improving our knowledge of all of these things and more. And it is why we look at a house as a system in which we cannot change one thing without affecting other things that could potentially create serious problems for the homeowner and the occupants. We are dedicated to protecting your health and safety and the durability and market-value of your home at the same time as doing everything we can to help you save energy, lower your utility bills, and improve the comfort of your home.

CONTACT US – Energetechs, Inc., – ph.