Wall Insulation Materials: Cellulose & Retrofit Foam
Posted on: Apr 7, 2011 Category:Insulation
Cellulose or Retrofit Foam?
Cellulose: One common form of wall insulation is cellulose. The cost of cellulose is low so it is a good method to use in new construction because your wall cavities are open allowing for the high density required for effective r values (3.5 PCf pounds per cubic foot and a 3.2 r value in inches). However, cellulose cannot withstand strong winds and should never be placed where water can infiltrate it.
Unfortunately when cellulose is used to fill an existing cavity (a home is retrofit) it is often done with a loose fill insulation and does not cover the required area to affect appropriate r values. Most commonly I find here in Ann Arbor, MI. That people have paid thousands to retrofit their walls with cellulose only to find the house cold and drafty again.
There are a few reasons for this:
- The installation/contractor did not blow it in with the high density required
- The installer does not understand building science and did not run extension wands up and down the walls for true coverage
- They did not realize cellulose bridges on existing wires or existing batts so you end up with whole areas completely uninsulated.
The worst part about the incorrect application of cellulose insulation is when a thermal scan is done you can see all the cellulose at the floor level and nowhere else.
My recommendation would be to use retro-fit foam insulation when upgrading existing homes. There are several types of foam on the market (even do it yourself kits) however it takes a lot of research to understand exactly what you are getting for your money. Foam is able (if installed properly) to achieve much higher r value, act as a true air barrier, true vapor barrier, and fill or seal voids in interstitial spaces (your wall cavity and chases). In my next blog I will cover the different foams and applications.
If you would like more information, visit our insulation pages or contact us. We're always happy to help!
April Rue
Ms Green Construction
