San Francisco · City and County of San Francisco
Mold Inspection in San Francisco, CA
Thermal imaging, moisture mapping and lab-analysed mold samples — from an inspection-only company that never sells mold removal.
San Francisco is a harder place for mold than most of the Bay Area, and for structural reasons rather than bad luck. The marine layer keeps exterior walls damp for long stretches, west-facing walls take wind-driven rain, and much of the city's housing is attached — so a moisture problem in one building can show up in the one next door.
The housing stock compounds it. Post-1906 Edwardians were built fast, with thin wall cavities and no vapour barrier, and later remodels often sealed those walls up without adding ventilation. Ground-floor rooms and in-law units built into garages are especially prone, because they sit close to grade in a foggy climate with little air movement.
That is why a mold inspection here is about finding the water source, not just the stain. Clean the mold without fixing the moisture and it comes back.
Local Findings
What comes up most in San Francisco
These are the findings this inspection is actually looking for here — drawn from how San Francisco was built and where it sits, not a generic list.
Mold behind bathroom tile and under vanities
Bathrooms remodelled without upgrading ventilation are the most common source of indoor mold I write up. The tile looks fine; the wall behind it is not.
Condensation mold in exterior-wall closets
A cold exterior wall plus no air movement inside a closet produces surface growth on drywall and on stored contents. It is frequently mistaken for a leak.
Window sills and frames on single-pane glass
Original single-pane windows shed condensation onto the sills all winter. The result is persistent growth at the frame and staining below it.
Damp ground-floor and garage in-law units
Rooms close to grade, with little ventilation and often converted without a moisture barrier. These are where hidden growth turns up most in the city.
Hidden growth from old roof or plumbing leaks
A leak that was fixed years ago often left wet insulation and framing behind it. The repair stopped the water; nothing dried the cavity.
Moisture crossing shared walls
Most San Francisco buildings share walls. A problem that starts next door regularly shows up on your side first.
How we test
Full visual assessment
Every accessible area, including attics, crawl spaces and under sinks.
Infrared thermal imaging
Spots damp material behind an intact wall or ceiling without opening anything up.
Calibrated moisture meters
Confirm and measure what the thermal camera suggests.
Humidity readings
Tell a condensation problem from an active leak — the two need completely different fixes.
Lab-analysed mold samples
When it helps answer the question, we take surface swabs and settle-plate air samples and send them to PRO-LAB, an AIHA LAP-accredited laboratory (ISO/IEC 17025). The lab results are added to your report.
Why inspection-only matters
We are inspection-only. We do not do mold removal and are not paid by anyone who does, so we have no reason to make a problem look bigger than it is. You get an honest, documented report you can hand to any remediation contractor.
How the inspection works
- 1
Pre-Inspection Survey
We discuss the property's history — past leaks, water damage, and any odors or symptoms you've noticed.
- 2
On-Site Inspection
A thorough visual, thermal, and moisture assessment of every accessible area of the property.
- 3
Moisture Source Tracing
Wherever the thermal scan or moisture meter flags an elevated reading, we trace it back to find where the water is actually coming from.
- 4
Clear Report
You receive a plain-English report with findings, photos, and practical next steps — delivered the same day.
What you get
- Find hidden moisture before it becomes a major repair
- Protect your family from mold-related health issues
- Documented findings you can use in real estate negotiations
- No conflict of interest — we don't sell remediation
A standard visual, thermal and moisture assessment. Larger properties are quoted before we book. Call for a fast, transparent quote.
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