Dormant Mold, Real Risks, Smart Fixes

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ver wondered why “dormant mold” keeps coming back the moment the seasons change? We pull back the curtain on what dormant really means, why 50–55% humidity isn’t a cure by itself, and how a moldy subfloor turns into a hidden hazard when spray foam goes on too soon.

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AJ joins me to tackle a real homeowner question from a 1927 house with a tight crawl space and visible mold. We break down the fruiting-body concept so you understand what you’re seeing versus what’s inside the wood, then dig into wood moisture content, leak pathways, and the blind spots created by covering the subfloor. You’ll hear why foam is great for targeted air sealing at penetrations and rim joists, but risky when used to blanket a subfloor that hasn’t been remediated and dried. We share simple checks for toilet flange leaks, ice-maker lines, laundry connections, and bath drains—plus why you should listen for drip sounds on plastic ground covers as an early warning.

From there we lay out the correct order of operations: remove visible growth, eliminate the moisture source, apply a root-killing treatment, verify dryness with a moisture meter, then insulate smart. Instead of burying problems, focus on sealing big gaps, insulating crawl space walls to reduce the stack effect, and keeping the subfloor visible for inspection. We talk practical targets for wood moisture, sizing dehumidification, and how to balance energy savings with long-term durability in older homes.

If you’ve ever been told to “just keep humidity under 55 and spray foam it,” this conversation will save you money and headaches. Hit play to get a clear plan for mold remediation, moisture control, and crawl space insulation that protects your home for the long haul. If this helped, subscribe, share it with a neighbor, and leave a quick review—what’s your biggest crawl space question right now?

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