Replies

1. 
   user-577475 | Apr 09, 2011 02:47pm | #1

   I've had some success with blown in cellulose in a similar retrofit situation. You can generally have it done, or do it yourself, with a 1" or larger hole in either the ceiling or floor drilled at each end of the floor span in each truss space. Depending on how deep your floor trusses are, it may take a lot of cellulose but it is still one of the lowest cost per cubic foot of insulation and is recycled material.

2. 
   BobHr | Apr 11, 2011 11:35am | #2

   Was the foam applied to the underside of the floor? If there did it correctly a 2lb foam will be an air barrier and a vapor barrier. Were the ducts sprayed too?

   Does that room have an air return. Air returns will suck a lot of air from adjoining spaces. If they are not well sealed you run the risk of sucking any fiberglass or cellulose insualtion in to your ducts.

3. GBA Editor
   Martin Holladay | Apr 11, 2011 05:55pm | #3

   Darryl,
   Three inches of closed-cell spray foam gives you an R-value of about R-20. That's OK, but not great. Still, it should be enough to avoid cold floor problems. If you have cold floor problems, it may be because of a defective heating system, not a problem with your insulation.

   If you want to upgrade to R-40, you can always have more spray foam installed.

4. 
   user-968787 | Apr 11, 2011 08:12pm | #4

   Yes the foam is on the underside of the floor. The underside is still exposed. Drywall is going up this summer so this is the opportunity to improve the situation.

   Another 3" of spray foam is pretty expensive so i'm looking for an alternative.

5. GBA Editor
   Martin Holladay | Apr 12, 2011 07:27am | #5

   Darryl,
   Either fiberglass batts (as long as they are thick enough to completely fill the joist bay -- or, better yet, be compressed) or blown-in cellulose will add R-value to your floor assembly at lower cost than spray foam.