Condensation & Mold above insulated crawlspace
Doing a phased renovation / addition project on a 2,400sf cabin with a dirt floor block crawlspace ~4′-0″ high. In summer client reports mold blooms on the wood floors above – they had insulation installed in the crawlspace 10 years ago, batt stapled to the underside of the floor boards between the joists, and then onto the walls of the crawlspace. The cabin above is unconditioned log, and gets quite warm in the summer, and retains the heat and humidity. My hypothesis is that condensation is forming in the wood, or on the wood floors, when the outside temperature drops, or when it rains and moisture accumulates in the crawlspace. I plan to remove the insulation and clean the crawlspace, but I wanted some advice. The client is planning for an addition to the cabin in the near-mid future, which would possibly include geothermal wells for conditioning the space (currently, it has electric baseboard heat and nothing else.) Would I be well-served recommending that they pour a slab on grade in the crawlspace, and insulate the block walls with rigid, or will that not be sufficient? My thought is that, when the client builds the addition, this newly insulated and floored crawlspace could act as a plenum space, or at minimum, a mechanical space for duct runs or plumbing. What are your thoughts? Does the slab need to be insulated? The crawlspace is ventilated, and the vents could potentially be sealed, or at least closed in the colder months to maintain the internal cabin temperature. I would appreciate any thoughts and suggestions.
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