Foam and Wiring
A bit of foresight makes future electrical connections a snap
I know that foam insulation is popular with you guys. But as an
electrician, I'm concerned that it limits options for any future wiring.
Once it's in place, how can I snake wires through those walls if the
homeowner wants to put in another circuit or add a switch or receptacle?
— David, Newton, Mass.
Tom replies: We've used polyicynene foam insulation on a number of
projects because it doesn't trap moisture, is environmentally safe,
muffles sound, and seals every crevice where air might leak in or out.
Basically, we figure the benefits far outweigh the difficulty it might
cause when making future wiring changes. Actually, because the
insulation is fairly soft and forgiving, retrofitting wiring isn't as
bad as you think. On a recent project where we had to run wires from the
basement into an upstairs home office, we drilled through the subfloor
and wall plate, then pushed a fish tape right up through the foam. It
wasn't the easiest way to go, but I'm sure you've found that snaking
wires through fiberglass batts can be a challenge, too. Still, we do try
to anticipate the problems future electricians might face. In some
cases, we've put lengths of electrical conduit vertically in the walls
and capped both ends before filling them with foam. This way, wires can
be routed easily from one level to the next if anyone ever wants to.