In an effort to make the family room as cozy as possible, I’ve used some Great Stuff expanding foam to seal the walls, some fiberglass bats to insulate the walls, a giant pile of cellulose to insulate the ceiling, and some rolls of fiberglass to insulate the skylights. This is the last part of the insulation, and also probaly the most worthless, but I’m doing it anyway. After bolting some wooden furring strips to the brick wall to hang some drywall to, I noticed that there would be a 3/4″ gap in between the drywall and the brick, a perfect spot for some more insulation! This time I’ve used foam board insulation, which has a nice foil backing to help reflect the heat into the room. The foam only adds a few to the R-value, and considering the brick (which is an excellent insulator by itself) is in front of a insulated 2×4 wall, this was undoubtedly overkill, however it was only a few bucks to put in, and it was easy to do.

When used properly Great Stuff expanding foam is an awesome substance.  it sticks to pretty much anything, expands into gaps, and is water-proof.  Its designed to be used to insulate in little gaps and cracks that are two small for regular types of insulation.   Although it probably has a decent R-Value, its far to expensive to be used in any significant thickness, and is much more useful at preventing air leaks.   I used it on this outside wall to make sure that all the gaps along the bottom of the sill plate were plugged (some bugs had previously found that they weren’t)  as well as to seal around the sheathing where holes were cut for lights.  Ohh and if you’ve ever gotten this on yourself,  a little acetone before it dries takes it right off.  Just don’t let it dry because once it does its practically impossible to remove.