Common Questions
Can I paint over mold or use mold-killing primer?
Answer
No. CDC says painting or caulking over mold won't stop it from growing; fix the water problem and clean up all the mold first. The IICRC S520 mold standard says the same: mold-resistant coatings are meant for use after the mold has been removed, not as a cover over growth, and mold left under paint can keep growing if the surface stays damp.
In Texas, on a licensed remediation project, a coating or biocide can be used only if the assessor's protocol calls for it and the product is registered for that use.
What the sources say
“Painting or caulking over mold will not prevent mold from growing. Fix the water problem completely and clean up all the mold before you paint or caulk.”
“Mold-resistant coatings should not be used as encapsulants over mold growth (Condition 3) but are intended for use after mold removal.”
“Mold-resistant coatings should not be used as 'sealants' or 'encapsulants' to contain or cover mold growth.”