Buyer’s Guide to Spray Foam Insulation

Spray foam insulation is made from polyurethane. This product is used to reduce air leakage in any structure. It is easier to install and more efficient than any other type of insulation on the market. It fills in all the nooks and crannies of unusually shaped areas. No area will be unprotected when spray foam insulation is involved. It does wonders for older, drafty homes, and large areas that need superior protection.

The Importance Of R-Value

Spray foam insulation comes in two main types. The most common type is open-cell, which has a density of around ½ pond per cubic foot. The second type is called closed-cell spray foam. This type of insulation has a density of around two pounds per cubic foot. The density needs to be as high as possible as this affects the R-value per inch. Spray foam insulation and traditional insulation with a higher R-value are more effective in sealing out drafts.

On The Job Preparation

To make this type of insulation, two components are mixed using special equipment. The mixing is done on a truck at the installation site. Using heated hoses, workers can put the chemicals in a mixing gun and spray them into the surfaces needing coverage. As soon as the chemicals are mixed, a reaction occurs. The liquid turns to foam, which will expand and harden.

If it is a small job, then the builder can use disposable tanks that have two-component cells. These tanks come in various sizes and will run anywhere from $300 – $600. If the job is very small, aerosol cans can be used. They are around $5.00 a can at most hardware stores.

Open Cell Insulation

Open-cell spray foam insulation has an R-value of 3.5 to 3.6 per inch. While the cost will vary greatly, it will cost around. $1.20 per square foot to insulate the area. It is best for walls, ceilings, and roofs. It is relatively vapor permeable, so if it is used in a cold climate, the foam’s interior should be covered a vapor retarder. A special vapor-retarding paint can do the trick.

The blowing agent in open-cell foam is either water or carbon dioxide. In place of the petrochemicals, some foams are made from natural materials like soybeans. This foam creates an effective air barrier. A downside is that this type does absorb and hold water. It has a lower R-value per inch, and it is vapor permeable. Depending on the application, the permeable nature of this spray foam insulation can be a drawback.

Closed-Cell Spray Foam

Closed-cell spray foam has an R-value of about 6.5 per inch. Though the cost will vary widely, it will take around $2 to $3 per square foot. It is best used under slabs, and for walls, ceilings, and roofs. The high R-value of this type of insulation is less expensive than using fiberglass or cellulose. Unfortunately, it is the most expensive type of residential insulation. Keep in mind, when installed properly, it will perform better than any other insulation available.

This insulation provides an excellent air barrier, is waterproof, and acts as a vapor retarder. Some say it has a glue-like tenacity. However, that just adds structural strength to the area applied. This type of spray foam is often used in new construction. It is effective at sealing the joists in the attic or the partition top plates. Green builders don’t like to use close cell spray foam as it has hydrofluorocarbons, otherwise known as HFCs. These HFCs are known to have high global-warming potential.

Spray Foam Is Superior In All Applications

Though the costs are a bit more than traditional roll insulation, the benefits far outweigh the price. The ability to get into even the smallest of spaces makes the energy efficiency of spray foam better.

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