Insulating Brick Walls
How to add a layer of warmth on the inside
We are renovating an extremely old house (100+ years). One room has
three outside brick walls. What is the best way to insulate the room
from the inside?
— Frank, Carleton, MI
Tom Silva replies: If the brick has one-inch firring strips and you're going to
tackle this yourself, I'd use one-inch foil-covered sheets of foam
insulation. Cut strips to fit tightly between each of the firing strips.
Then take sheets of the insulation, 4 feet x 8 feet, and cover the entire wall.
Nail with 1 1/2-inch roofing nails. You won't need a lot of nails, but try not to rip or damage the foil. Make
all joints tight. Then tape all seams with foil tape. Cover the foam
with wallboard and plaster. You'll have to build out the wood trim
around your windows or door to make up for the added insulation and
wallboard. You'll also need longer screws for the wallboard, 2- to 2 1/2-inch screws.
If you're hiring a contractor, spray foam wall is a good
alternative. This liquid is injected and expands into foam. The excess
is then shaved off and the walls are ready for wallboard and plaster.