FAQs
We’ve pulled together the most common questions posted on the GBA site.
Q. Do I need a vapor barrier?
A. Probably not. For more information, see:
Do I Need a Vapor Retarder? and
Vapor Retarders and Vapor Barriers.
Q. How do I insulate my cathedral ceiling?
A. For everything you need to know, see How to Build an Insulated Cathedral Ceiling.
Q. How do I insulate my basement wall?
A. For everything you need to know, see How to Insulate a Basement Wall.
Q. How do I fix my crawl space, which is leaky / cold / moldy / poorly insulated?
A. For everything you need to know, see Building an Unvented Crawl Space.
One Comment
I'm trying to reduce ice dams, and I've noticed a lot of snow melts around the central chimney in my roof. (The chimney is used only to vent an oil boiler.)
One of the suggestions in the GBA article linked below is to build an insulated and air-sealed chimney enclosure, with a 2" internal airgap to meet building fire codes.
https://www.greenbuildingadvisor.com/question/insulating-an-interior-chimney
Wouldn't the airgap retain and focus heat on the roof around the chimney? Is this really better than letting the heat mix with cold air in the attic, then vent through the ridge? Would it be more effective to use a high heat insulation that can be attached directly to the chimney, such as ceramic fiber or calcium silicate? It seems like this would prevent heat from escaping the masonry of the chimney in the first place. (It would also eliminate convection that would occur in an airgap.) And would insulation like this need to be foil-faced to be effective?
The ridge vent on my roof stops two feet from the chimney to avoid the possibility of perched water leaking directly into the vent. So, for me there would be no practical way to vent a chimney enclosure into the
ridge.
Thanks in advance.
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