Guided evidence worksheet
Crawl-space moisture: ground vapor, outdoor humidity and leakage
Log outdoor dew point, crawlspace temperature, relative humidity, ground condition and plumbing state at repeatable times.
Reasoning guardrail
Separate the routes before choosing a repair.
A musty odor at the floor above does not prove that visible mold is directly beneath that room.
- Trigger
- Season, weather and whether wetting is broad or localized separate the routes.
- Area
- Crawlspace
- Provenance
- Original explanatory diagram, not a site photograph.
1. Freeze the evidence
What happened first?
2. Competing hypotheses
Record evidence for and against each route.
Warm humid outdoor air cooling in the crawlspace
Outdoor air enters, cools and raises surface relative humidity or condensation risk.
Evidence that raises fit
Evidence that lowers fit
Notes
Ground moisture or capillary vapor load
Exposed soil or wet perimeter ground supplies persistent moisture to the crawlspace.
Evidence that raises fit
Evidence that lowers fit
Notes
Local plumbing or drain leak
A supply, waste or condensate route creates concentrated wetting independent of seasonal air.
Evidence that raises fit
Evidence that lowers fit
Notes
3. Decision points
Change one condition at a time.
Is wetting broad and seasonal or concentrated below one service route?
Yes: Broad seasonal wetting favors air or ground vapor; local wetting favors plumbing.
No: Improve spatial measurements before selecting a pathway.
Observed answer and evidence
Does outdoor dew point predict the crawlspace humidity rise?
Yes: Treat warm-weather air exchange as a leading mechanism.
No: Check ground and liquid-water sources.
Observed answer and evidence
Safety boundary
Stop rather than create a better clue.
- Do not enter confined crawlspaces with poor air quality, standing water or unsafe access.
- Stop if sewage, electrical hazards, animals or structural instability are present.
5. Current conclusion
