Parapet wall insulation from inside
user-6610113
| Posted in General Questions on
This question builds off of the previous one about wall insulation on a 100 year old stucco house with parapet walls in climate zone 3.
The parapet walls are 8 inches wide externally and are capped with brick that is then capped with a metal cap. The parapet walls are hollow and continuous with the wall below. However this is very little access from below.
The roof is leaking and needs to be replaced so that may improve access (see next question).
How would you recommend insulating parapet walls from the inside in this case?
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Replies
Matt,
This is an air-sealing challenge. Really, the questions around insulation aren't that interesting -- the issues that should keep you up at night all concern air sealing.
Ideally, you are establishing your thermal barrier (air barrier + insulation layer) at the ceiling level (corresponding, I assume, to the flat roof). Somewhere in your wall assembly, you also have an air barrier. Your challenge is to connect the air barrier in your ceiling with the air barrier in your wall. That air barrier needs to cut across the balloon-framed studs that extend skyward to create your parapet.
Options include lots of carefully installed blocking (2x4s? Rigid foam?), sealed with caulk, or big globs of spray foam (in some cases the spray foam can be installed against temporary backing like wads of fiberglass insulation). You need good access and attention to detail.