I am planning to insulate my basement walls (full foundation) this spring using spray foam insulation on the concrete walls. I should note that I am located in Maine, I have radiant heat on the first floor, with insulation underneath. With the insulation under the first floor the basement temp often reaches 38-44 deg F. in the winter months. For my workshop I plan to build 2×4 walls about 1-2 inches away from the concrete walls and then spray the foam (similar to that shown in a recent FHB magazine). My concerns/questions are: will insulating the basement walls create possible frost issues on the outside walls of the foundation (with less heat escaping the foundation walls)? if this is a problem, would only spraying the above-grade area on the walls be a better option? or, since the basement temps have already been so cold, would I have already experienced any problems if they were going to occur? I should mention that the exterior backfill is not any special well-draining soil, only existing soil was used for backfill.
The other concern is moisture. If I insulate the walls from the top down, and moisture wicks up through the floor, would I have any issues with the moisture not being able to go anywhere except up through the floor?
Thanks in advance for any advice.
Steve
Replies
I'd be concerned about how you might keep a watch on your basement wall for any cracks, but that problem exists with most coverings. It's probably easier to replace a piece of polystyrene, though, since you don't need to rent the machine again.
Two q. for venting & insulating walls in moderate Western NC climate. My recently constructed dried-in walls are Tyvek, 1/2" foam or ply at sides, 2x4. Codes have made many areas (esp. south facing wall with lots of glass) mostly stud and glass--5 to 6 studs nailed together, 2x10 almost continuous header--so have little room for insulation, which I'd like to be wet-sprayed cellulose. SO should I nail 1x 1 1/2" strapping on studs to get a little extra insulation and help prevent thermal bridging, or is it worth the effort (problems for electrical boxes, trim,etc.)? Second, venting the exterior wall: it's easy to vent those when the sheathing is horizontal, but my board & battens will run vertically, preventing airflow from going top to bottom. So again is it worth it to put 1 x 1/2 strapping horizontally over the horizontal purlin-nailers in the walls or should I just plop the boards over the Tyvek and hope for the best?
Hey you are in luck, pickup FHB #169 on sale now it has an article that tells you exactly what to do, you can also check http://www.buildingsciences.com