Insulating a converted attic
jsfinewood
| Posted in Energy, Heating & Insulation on
In trying to insulate the converted attic of a Cape Cod style home, the end walls were found to consist of stucco on the exterior of cinderblock walls, with drywall on 1 bys, leaving only about 3/4″ between the drywall and the exterior cinderblock wall.
Looking at the FHB website, I’m not sure what can be practically done from the inside.
Would a 2″ layer of XPS directly glued onto the existing drywall provide insulation without trapping moisture?
Would a particular brand be preferred to prevent/avoid moisture trapping?
Could I then install a new layer of drywall directly onto the XPS?
Thanks,
John S.
Replies
Usually, advising which state the project is located, would help a lot in finetuning the relevant code section. In this case I have chosen Alabama as a starting point, below are some links that should assist.
When insulating w/ foam one should be aware of code Section R316, which is dedicated to foam and plastic installations:
https://up.codes/viewer/alabama/irc-2015/chapter/3/building-planning#R316
For the new insulation to trap moisture, it would have to act as a vapor barrier. The use of foam for insulating a concrete wall is covered in code Section R702.3.4:
https://up.codes/viewer/alabama/irc-2015/chapter/7/wall-covering#R702.3.4
Sorry, location is southwest Ohio.
To insulate you should remove drywall and apply whatever insulation directly on to the concrete blocks to help avoid condensation in the cold months.