Tricks on insulating an already finished wall
Last summer I sought some opinions on whether or not it was worth demoing existing plaster walls while we renovated an upstairs bedroom (the last room of a lengthy total reno, which saw us insulate or re-insulate almost all non/poorly insulated spaces). At that time we were both very tired of renovation and just wanted to “git ‘er done” and went ahead and finished it. Now that it’s cold, and I can see how well it plays with a newer efficient forced hydro air system that works fine for the rest of the house, I regret the decision.
The two walls in question are a masonry gable end wall, and a 2×4 wood dormer wall. The dormer wall is full of 50’s era Balsam Wool. It’s a little chilly but not horiffic. The big problem is the brick block, which from outside is solid brick, 4″ cinder block, 3/4″ air gap via furring strips, and an inch or so of gypsum board and brown/finish plaster. When it gets below 30 it becomes a refrigerator, and you can almost feel a draft blowing in through it. With the door open the upstairs air mixes in and keeps it manageable, but close the door and suddenly penguins show up asking to be let in :).
I figure the dormer wall can be just left alone or worst case I could punch some holes, dense pack, and patch. The masonry wall however is a real challenge. The room is DONE so wrecking the wall would be a significant undertaking, including re-trimming the finished windows. I could probably get a supplemental space heater to help keep it in check, but it seems like such a shame after all the work. I have also read that filling the air gaps with perlite from above may be somewhat effective, but I only have 3/4″ to work with – and I’d have to hunt and peck to find the gaps through a top plate over the masonry in the attic. Finally, I could just leave the plaster and frame a wall in front of it and insulate and re-sheetrock/trim (lots of work) but I am not sure if that will create any condensation issues.
So I guess my only question is whether anyone has an opinion on the best approach – maybe something I have not even thought of yet? The only thing that won’t fly is to insulate from the outside – the brick is part of the look of the house. At this point I’m open to anything else that would help w/o too much destruction.
Thanks as always!
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