Mold is the point where a water loss stops being a construction problem and becomes a health and liability problem. It is also the point where we hand the job to somebody else and wait, which is not what most homeowners expect a contractor to say.
- Address the moisture source promptly and document the affected areas before reconstruction begins.
- In a California rental, visible mold can raise a code or habitability concern. The statute has exceptions and calls for an official determination.
- We do not self-perform remediation. A remediation provider addresses the affected materials and documents the reconstruction handoff.
- California has no mold-specific contractor license. Ask a provider about its written work plan, documentation, and how it will verify the moisture source is addressed.
Why mold shows up so fast
Mold spores are common in buildings. When moisture reaches materials such as paper-faced drywall, wood framing, insulation, and dust, the moisture source needs to be found and addressed before reconstruction. Documenting the affected areas early gives the mitigation and rebuild teams a clearer handoff.
The most common mold we find in Bay Area homes is not from a dramatic flood. It is from a slow leak nobody knew about: a shower pan, a supply line inside a wall, a drain under a slab, a bathroom with no working exhaust fan. By the time there is a stain on the drywall, the cavity behind it has been wet for a long time.
What California law actually says
California takes an unusual position here. There is no state mold specific contractor license, and the state has never adopted permissible exposure limits for indoor mold, despite the 2001 Toxic Mold Protection Act contemplating them. So there is no official number that says a house is clean.
SB 655 added visible mold growth to California's list of conditions that can make a building substandard when it endangers occupants or others and is determined by a health or code enforcement officer. Minor mold on surfaces intended to get wet is excepted. For a rental, document the condition and notice promptly. Civil Code 1941.7 addresses when the landlord's repair duty related to mold arises.
If you own a rental in San Jose, that is the sentence to remember. We cover the operational side in water damage for property managers.
How remediation is supposed to work
IICRC publishes the S520 professional standard for mold remediation. A remediation provider should identify the moisture source, define the affected area, explain its containment and cleaning plan, and document what is ready for reconstruction.
Two things distinguish this from a bleach and a Saturday. Containment, which is what keeps a bathroom problem from becoming a whole house problem. And verification, ideally by an independent indoor air quality professional rather than the company that did the removal, since a firm testing its own work has an obvious conflict.
A qualified emergency water mitigation provider handles extraction, drying, and documentation before the rebuild handoff. We handle reconstruction after that work is ready for handoff.
Why we will not do the remediation ourselves
We do not self-perform remediation. The work calls for a different scope, equipment, and documentation from construction. We rebuild after the remediation provider has documented the completed handoff.
The rebuild after remediation
Once clearance is documented, the rebuild is ours: insulation, drywall, texture matched to the surrounding wall, paint, trim, flooring, and rebuilding whatever cabinetry or tile came out. Two details matter more than they look:
- Fix the cause, not just the damage. If the mold came from a missing or undersized bathroom exhaust fan, or a fan venting into an attic instead of outdoors, then rebuilding without correcting the ventilation guarantees a repeat. Same with a shower that was never properly waterproofed behind the tile.
- Waterproof the rebuild properly. Tile and grout are not waterproof. The membrane behind them is, and it is invisible once tile goes on, which is exactly why a rushed crew skips it.
We will not build over material that has not been cleared. It is the one part of a schedule we do not compress, because building over mold means opening the same wall twice and the second time is on somebody's conscience.
What to check before you hire anyone
- A written plan explaining the moisture source, affected materials, containment, and reconstruction handoff.
- A written protocol: containment, negative air, HEPA, source correction, and how clearance is verified.
- Independent post remediation verification rather than self certification.
- For the rebuild, a CSLB licensed contractor. You can verify any California license number on the CSLB site in about a minute.
Common questions
Is mold remediation regulated in California?
Can I just clean mold with bleach?
Does insurance cover mold remediation?
Sources
Water damage to put back?
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- CSLB #1050108
- Serving San Jose and the South Bay
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