Is there anything worse than getting midway through a renovation and then suddenly wondering whether you’ve got some important detail all wrong?
That seems to be the predicament of William Lucrisia, who’s in the midst of an insulation upgrade at his house north of Seattle.
“The house was heated by propane,” he explains in a Q&A post at Green Building Advisor. It was a cost that was hard to get hold of, especially with some of the design [features] of the house (high ceiling).”
So Lucrisia set about making improvements, and his plan involved gutting interior walls and adding mineral wool insulation and then a layer of foil-faced polyisocyanurate insulation before applying new gypsum drywall.
“I am a bit ‘OCD’ now that the living room is for the most part done… I wonder if I am trapping moisture inside my walls, having used the foil-faced polyiso just behind the Sheetrock… Was it okay to do what I have done?”
That’s the question for this Q&A Spotlight.
The walls are OK, but what about the ceiling?
The foil face of the polyiso insulation won’t allow the passage of moisture, but Lucrisia should have no problems as long as the walls can dry to the exterior, says GBA senior editor Martin Holladay. And that, Lucrisia says, appears to be the case.
“I presume things will dry from the exterior,” he writes. “It’s typical sheathing and siding on the exterior. It’s just that my wooded area with the rain and cool air air scares me with some of the stuff I have been reading lately.”
But a related issue concerns the ceiling. A second photo that Lucrisia posts with his question shows a ceiling finished with slats of wood, and Holladay wants to…