Published on November 28th, 2014 | by Henri0
Insulating a home built with terra cotta blocks
Q. We have an old house made out of terra cotta block from top to bottom. We recently insulated the inside walls with R-13 and drywall. Then we had our outside done in vinyl siding and the foam insulation 3/4 inches thick. Our house is still a little chilly at 69 degrees. Any suggestions on how to keep our house warm? Also we were going to invest in a pellet stove. Any suggestions on this?
A. I assume you studded the inside of the house’s exterior walls and put R-13 fiberglass between the studs. That, together with 3/4-inch rigid foam, gives you walls with only R-17 – not too exciting for a cold climate.
There is also the possibility that convective currents within the terra cotta blocks rob you of some of the R-factor. This is difficult to overcome unless the blocks had also been filled with insulation.
It would have been preferable to apply 1-inch thick rigid foam insulation directly to the terra cotta walls and then stud the walls, if you have the space, with 2-inch by 6-inch studs and R-19 fiberglass insulation. Then outside, I would have used 1-inch thick rigid insulation instead of 3/4-inch. This would have given you an R-29 plus.
Now it seems as if your only option is to get warmer with a pellet stove. Pellet stoves are very effective and, as long as pellets are readily available at reasonable prices, they are a good way to go.by