Start with a dated symptom timeline
Write down when the condition was first noticed, what the weather had been doing and whether plumbing or an appliance had recently been used. Add the time it takes for water, staining or condensation to appear and disappear. Repeat the entry during more than one event when that can be done safely. A timeline exposes patterns that a one-time visit may miss and gives every reviewer the same facts.
Map location, height and spread
Identify the first visible location rather than only the largest wet area. Note whether it begins at exposed soil, the base of a foundation wall, a penetration, a pipe route, a floor-joist bay or a cold surface. Record height and direction of spread, and include a fixed reference in photographs. These details help distinguish movement across a surface from moisture appearing within an assembly.
Check exterior water routes from outside
Observe roof runoff, downspout outlets, low areas, surface grade and visible discharge points from accessible exterior locations. Do not excavate or claim that a hidden perimeter drain is clear based on a surface observation. Compare the exterior location with the first interior sign and note whether the pattern changes after different rain intensities. Exterior observations narrow questions; they do not prove a buried system’s condition.
Compare plumbing timing separately
If the condition follows fixture use, laundry, a water heater, irrigation or another known event, record the exact event and affected area. A plumbing question can coexist with rain or ground moisture, so do not remove other source categories from the record prematurely. Shut off water only when that is safe and appropriate, and route supply, drain or equipment concerns to a qualified plumbing review.
Record exposed soil and membrane continuity
From safe access, note exposed soil, standing water above or below a membrane, open seams, wall transitions, penetrations and attachment points. Do not lift a membrane to investigate underneath it. Natural Resources Canada describes ground moisture barriers as part of crawlspace moisture control, but material and detailing choices still depend on whether exterior water, drainage, plumbing and wet materials have been addressed.
Distinguish condensation from liquid-water clues
Condensation often appears on cool pipes, ducts, foundation surfaces or framing when warm humid air meets a colder surface. Record outdoor conditions, indoor humidity if a reliable reading is available, and which surfaces are affected. Do not assume every droplet is a leak or every musty odour is mould. Health Canada recommends identifying and correcting the moisture source rather than relying on appearance alone.
Escalate safety and material concerns
Stop entry where standing water is near electrical equipment, access is unstable, structural damage is suspected or material may be contaminated. Do not disturb insulation or suspected mould to improve a photograph. Health Canada advises qualified help when the source or corrective action is unclear and does not recommend routine air testing as a substitute for finding the moisture problem. Keep health questions with a healthcare professional.
Health Canada advises finding and correcting the source of indoor moisture and notes that crawlspaces belong in a visual moisture inspection. Natural Resources Canada explains dampness checks and crawlspace moisture-barrier considerations. Use these sources as general evidence boundaries, then confirm the actual property condition.
Health Canada — Moisture and mould indoors · Natural Resources Canada — Basements and crawl spaces
Sources reviewed September 22, 2026. Confirm current requirements for the exact address and proposed work.