Most crawl space problems are slow. They build up over months while no one looks. A 15-minute seasonal walk-through catches the vast majority of issues before they become invoices.
Spring (March–May)
- Check for water staining from winter freeze-thaw events.
- Inspect grading: did frost heave change drainage paths?
- Test the sump pump with a five-gallon bucket of water.
- Replace the dehumidifier filter and verify the drain line is clear.
Summer (June–August)
- Verify the dehumidifier is holding RH below 55% during peak humidity.
- Check ducts for condensation drip marks.
- Look for new fungal staining on joists — high humidity months are when growth accelerates.
- Inspect the rim joist for moisture intrusion.
Fall (September–November)
- Clean gutters — the leading cause of crawl space water issues.
- Check downspout extensions: 6–10 feet from the foundation, sloped away.
- Seal any new gaps in the foundation walls before rodents move in.
- Verify the access door gasket is intact.
Winter (December–February)
- Insulate any exposed pipes in the crawl.
- Check for cold-air infiltration through the rim joist.
- Verify the dehumidifier still cycles — some units idle in low temps.
- Inspect for animal entry (chipmunks, mice) finding warmth.