What is R-value?

R-value measures insulation’s resistance to heat flow. It can also be referred to as “thermal resistance.” The R-value of different insulating materials must be based on test methods established by the American Society of Testing and Materials (ASTM). Don’t forget that R-values are determined by material type, thickness, and installed weight per square foot, not by thickness alone.

What is the R-Value myth?

To the average person the higher the R-value number of your insulation, the warmer you should feel in the winter and cooler in the summer. The reality is something totally different as the R-value listed on insulation is not arrived at under real world conditions making them extremely misleading to the consumer. For instance, fiberglass insulation is generally assigned an R-value of approximately 3.5. It will only achieve that R-value if tested in an absolute zero wind and a zero moisture environment. Zero wind and zero moisture are not real-world. The average home with all its doors and windows closed has a combination of air leaks equal to the size of an open door, hence the reason why so many people feel that their homes are drafty. Even if you did a perfect job of installing Fiberglass or Cellulose insulation in your home and were to bring the air infiltration close to zero from one side of the wall to the other, you would still not stop air from moving vertically through fiber based insulation itself, in ceilings and walls. Water vapor from the atmosphere, showers, cooking, breathing, etc. constantly moves back and forth through walls and ceilings as well dropping Fiberglass or Celluloses insulation’s R-value — as much as 50 percent or more as well.

By some estimates, 50-60% of your heat escapes through light fixtures, vents, and directly through your ceiling into the attic and out your ridge vent or soffits. This is why when considering insulation, addressing deficiencies in the attic can give you the biggest bang for your insulation dollar.

The only way to stop the moving of air and moisture within a building’s structure is with an air and vapor barrier. One inch of spray Polyurethane foam insulation properly installed throughout the building structure can prevent more heat loss than all the fiber insulation that can be crammed into the structures walls.

What is the Stack Effect?

The “stack effect” is when warm air moves upwards in a house. This happens in summer and winter. Warm air rises – because it’s lighter than cold air. So when it rises, what happens? It escapes out of the upper levels of our homes through recessed lighting fixtures, fan fixtures, etc. But we can’t create a vacuum in our homes so when air escapes new air has to come in to replace the air that escaped. Where does the new air enter the house? …at the lower levels, through your floors above the crawl space, at your top plate, around windows, through under-insulated walls, vents and other leaks in the home envelope.

What is the difference between Closed-Cell and Open-Cell spray Polyurethane foam insulation?

Closed-Cell Foam

Closed-Cell spray Polyurethane foam is highly dense and when sprayed expands up to 30 times its original liquid volume producing an R-value per inch of 6.4+. In Closed-Cell spray foam, cells or bubbles in the foam are compacted together, are not broken and each is filled with an inert gas selected to make the insulation value of the foam as high as possible. An example of Closed-Cell foam insulation that we benefit from every day would be the insulation found in your refrigerator and freezer.

The advantages of Closed-Cell foam include its strength, higher R-value, and greater resistance to the leakage of air or water vapor making it ideal for windy, damp and water prone locations, such as coastal areas, below grade, crawl spaces, or for the whole house. For many of our clients, Closed-Cell foam is the product of choice. While more expensive than Open-Cell foam because of its density, at 1 inch thickness Closed-Cell foam develops an air barrier and at 2 inches a moisture barrier. Closed-Cell Spray Foam is the only FEMA approved flood resistant insulation material.

Open-Cell Foam

Open-Cell spray Polyurethane foam is soft – like a foam cushion in a pillow and is an excellent air and sound insulator. Unlike Closed-Cell foam, Open-Cell foam is less dense, with each Cell in the foam being broken, thus allowing air to fill all of the spaces in the material. Upon spraying Open-Cell foam expands up to 150 times its original liquid volume, thereby filling all nooks and crannies in the wall cavity. When spraying is complete, the excess foam is shaved off the studs, leaving a flat surface over which dry wall or other material can be applied. With an R-value of 3.7+ per inch Open-Cell foam gives you an air barrier @ 5 inches of thickness. Uses for Open-Cell include spraying directly to all walls of a house, and as sound proofing for media rooms. Open-Cell foam may also be direct sprayed to roof decks.

Is spray Polyurethane foam good for soundproofing?

Both Open-Cell and Closed-Cell spray Polyurethane foams are effective for reducing noise from outside sources by sealing cracks and gaps that allow sound to travel through the walls, floors and ceilings into the building. Of the two, Open-Cell foam has the best soundproofing capabilities.

If you spray the underside of a roof deck with spray Polyurethane foam insulation, should you vent the attic?

No, the application of spray Polyurethane foam insulation to the underside of the roof deck eliminates the need to vent the attic. Venting of attics primarily came about as a way to eliminate condensation buildup on attic insulation resulting from temperature differences between the inside attic walls and the interior of the building. Unfortunately, this venting also allows cold air into the attic in the winter and warm air in during the summer. With spray Polyurethane foam insulation a thermal and moisture gradient is provided allowing the space to become semi conditioned, within 10-15 degrees of the interior house temperature, thus preventing the development of dew point conditions in the attic.

At what point in the construction of my house should spray Polyurethane foam insulation be applied?

Spray Polyurethane foam insulation is professionally installed at the same point in the construction cycle as other types of insulation. This typically occurs after the rough plumbing, electrical wiring, and heating and air conditioning ducts have been installed, but before the interior walls are completed in new home construction. In some cases spray Polyurethane foam insulation can also be applied in older homes, to the inside of roofs and under floors after construction has been completed.

How does the spray Polyurethane foam insulation seal my house?

Spray Polyurethane foam insulation is a two component, sprayed in place insulation designed to provide superior thermal performance on virtually any substrate (wood, masonry, metal studs and joists). When sprayed on the substrate, the foam expands allowing it to form a monolithic seal to the inside surface of exterior walls, to the underside of the roof deck, beneath floors, and in basements and crawl spaces. The result is that air can no longer penetrate your house making it 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 spray Polyurethane foam insulation moisture can be reduced to the point that this will not be a concern.

Won’t sealing my house lead to indoor air quality problems?

If you are sealing the entire building envelope we always recommend some form of fresh air ventilation. Most building design professionals will advise you to seal the building structure as tight as possible and provide the necessary ventilation through an air exchanger attached to your heating and air conditioning system. In the winter, this simple machine brings cold fresh air from the outside and passes it by the warm stale air being expelled. This allows the fresh air to pick up the heat from the stale air, maintaining energy efficiency while providing a continuous supply of fresh air. In the summer, the opposite occurs giving the same results. In this manner, you can build an extremely energy efficient exterior shell using spray Polyurethane foam insulation while still providing controlled and energy efficient ventilation.
If you are retrofitting parts of your home, such as the attic, crawl space, or basement walls, you will probably not need to worry about your house being sealed too tightly as air enters the building envelope every time we open the door as well as through windows and locations within the home that typically are not reachable because of drywall etc.

Our position in regards to insulating a new home is that you will get only one chance to do the whole house. If you under-insulate you will regret it. In the unlikely event that you over-insulate the situation can be remedied with low cost ventilation systems as previously mentioned.

Can I use spray Polyurethane foam to insulate an existing home?

Yes, we can spray Polyurethane foam insulation on the underside of your roof deck, under crawl spaces, on basement walls, and into new additions or home renovation projects involving the removal of the existing drywall.

Will I save money if I insulate with spray Polyurethane foam insulation?

Yes, the installed cost of spray Polyurethane foam insulation is somewhat higher than Fiberglass and blown-in Cellulose. However, the higher initial cost is partially offset because of the sustainability of the insulation (it will not degrade over time like fiberglass and cellulose) and you may be able to downsize your heating and air conditioning equipment. Additionally, you will save in your heating and cooling bills. Studies suggest that homes insulated with spray Polyurethane foam use up to 40 % less energy than homes insulated with conventional insulation. Your savings may be greater or less depending on your life style, appliances, house site, number and size of windows, etc.

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