What to Do When You Find Mold
Mold is a symptom, not the problem. It grows where something has been wet, and it comes back if the moisture source is still there. The single most useful thing you can do right now is leave it undisturbed and go find the water.
Do this now
Leave it alone. Close the door to the room, or the cabinet, and stop using the space.
Turn the HVAC system off if there is a supply or return register in the affected room.
The system will move spores from one room into every room, and into the ductwork, faster than anything else in the building.
Go find the water. A supply line under a sink, a failed toilet seal, a roof penetration, a bath fan venting into the attic, a crawlspace with no vapor barrier, or condensation on a cold exterior wall.
Photograph what you can see without touching it, and write down when you first noticed it.
Keep anyone with asthma, allergies, or a compromised immune system out of the room.
Run a dehumidifier in the room if you have one, but do not aim a fan at the growth.
Lowering the humidity slows growth. Moving air across colonized material releases spores into the rest of the house.
What makes it worse
These are the ones that turn a manageable loss into an expensive one, or cost people their claim.
Don't spray bleach on it.
Household bleach is mostly water. On porous material it takes the color off the surface, leaves the growth in the substrate, and adds moisture to the exact material feeding it. It looks fixed for about a month.
Don't scrub it, sand it, or tear out drywall to see how bad it is.
Disturbing colonized material releases spores in numbers you cannot see and cannot get back. That is the moment a one-room job becomes a whole-floor job, and it happens in about ten seconds.
Don't point a fan or an air mover at it.
Airflow across growth is the most efficient way to distribute it through a house. Containment and negative air machines exist specifically to prevent this, which is why remediation looks the way it does.
Don't paint or seal over it.
Encapsulating growth without removing it and without fixing the water hides it until the paint bubbles. It also has to be disclosed at sale, and a home inspector with a moisture meter will find it.
Don't rely on a store-bought air test to tell you whether you have a problem.
Consumer kits grow something in nearly every house, because spores are everywhere and always have been. Sampling is useful for locating a hidden source and for verifying clearance after remediation, not for confirming what you are already looking at.
The clock
Mold begins colonizing wet organic material in roughly 24 to 48 hours, which means what you are looking at has been wet longer than that. The size of the remediation is set by how long the water has been running, not by how big the stain looks today. Finding and fixing the moisture source is the whole job. Everything else is cleanup.
Call us when
- The growth covers more than a small patch, or it is on drywall, insulation, or carpet rather than a hard surface.
- It came back after you cleaned it.
- There is a musty smell in a room with no visible growth.
- You are buying or selling and an inspector flagged it.
Once the first hour is over
What people read next, after the immediate part is handled.
The Idaho Mold Guide
Once the first hour is handled: is black mold dangerous, do you need a test or an inspection, are those dark joists still growing, and how remediation is priced.
Read itCrawlspace mold removal
If what you found is under the floor. Joists and subfloor cleaned under containment, with the ground moisture fixed so it does not come back.
Read itMold and moisture inspection
Free for the one spot you called about. $279 for the whole house, instruments, and a written report, credited in full against the job.
Read itIf it’s past what you can handle, call.
A person answers 24 hours a day. Even if it’s just a question.