How Thick Should Spray Foam Insulation be in my Attic?

If you're interested in having spray foam insulation added to your attic, you're probably wondering just how much needs to be applied.

The answer largely depends on the difference in temperature between your attic and outdoors.  There is a point at which spray foam insulation is no longer cost effective, so a professional contractor needs to determine just how much you actually need.

Here in Louisiana, the average temperature high for the state is about 93 degrees.  When we compare that to the cold storage temperature, we can calculate the most cost-effective thickness of spray foam insulation needed (about five inches, in this case).  Of course, the best amount of insulation can be different for each home.

Is there a recommended amount for most homes, though?

There is something that you need to known in advance about R-values.  An R-value is a term that we use for insulation's resistant to heat flow.  The higher the R-value of a product (like fiberglass or spray foam), the better it insulates your home.  Spray foam insulation has a much higher value than fiberglass, for example.

The US Department of Energy suggests R-values for different homes in America based on the local climate, and the average heating and cooling costs in your area. 

So if the ideal R-Value for your home is R-40, your contractor may only need to spray five inches of foam insulation.  This is compared to having to stack fiberglass as high as 14-16 inches to get the same results.

So what's the best way to know how much spray foam is needed?

A professional spray foam contractor should be able to determine this for you.  By inspecting your home, and understanding the average temperature in your city, an experienced spray foam installer will be able to best know exactly how much insulation you need. 

At Advanced Foam Insulation of Louisiana, we specialize in treating homes with spray foam to lower electric bills.  Not to mention added benefits like prevention of dangerous mold, and increasing your home's resale value.

If you live in the state of Louisiana and would like to get a free estimate, please call us today or click here to reach us by email.