Moisture Problems in Fibreglass Insulation?
Summary
If the sunroom is to be used in the colder months and heaters are installed to make it habitable, then heating the room above the crawlspace may cause the flooring to become considerably warmer than the outside air. Insulating this floor with fibreglass batts will not prevent warm-air loss to the underside of the sheathing, but will slow it down, unless a really well-sealed air/vapour barrier was installed. This warm air may condense inside the insulation, as it cools, creating a moisture and frost problem when the weather warms.
The solution to this is to remove the insulation from the underside of the floor and replace it with well-insulated skirting around the perimeter of the crawlspace. After that is done and a good air/vapour barrier is installed over the insulation and soil at the bottom of the crawlspace, adding heat to the crawlspace will complete the job. In that situation, heating the crawlspace will warm the underside of the floor sheathing and the insulated skirt will prevent cold-air infiltration, which would make the floor feel even colder in your current configuration.See the full content of this document
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Moisture Problems in Fibreglass Insulation?
QUESTION: About 10 years ago, a sunroom was attached to the back of my house, with access from the back door. The floor level of the room is about 12 inches from ground level. The floor was insulated with yellow fibreglass batts. The walls and ce...
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