I am getting ready to insulate an addition on my house that consists of double brick, 1×2 strapping, ten-test and 4×8 wood panel sheets. In order to minimize the floor space lost by this endevor and to avoid moving hot-water radiators, I plan to use 2 inch sytrofoam secured by steel channel to insulate the space.
Since the walls currently have little insulative value, the electrical boxes are mounted on the ‘warm’ side of the wall. However, when I add the sytrofoam, they will effectivly be mounted on the ‘cold’ side.
My question is: Will I have a problem with consendation in my electrical boxes, since they will be mounted to the uninsulated brick wall, and if so, how can I avoid it?
Replies
You should not have any problem with condensation. Many houses ariund here were built without insulation in the walls in the 40s, 50s, and 60s. Earlier one had metal boxes and latter ones had plastic. I have never seen signs of condensation in either type over 30 years of remodeling.
Dave
Seal the boxes tight. If no warm moist air passes through them, no condensation will happen. This is just good practice anyways for boxes placed in exterior walls.
I seal all of the openings in the back of the boxes, and the gap around them with caulk. You can also buy special plastic pockets that seal to a vapor barrier, if you are using one.
I do not think that the typical foam cover seals perform well.
One source of vapor barrier boxes:
http://www.efi.org/products/weather/lessco.html