What bleach does and does not do
What it does
- Lightens visible staining quickly
- Disinfects hard, non-porous surfaces like tile and glass
- Makes a room smell clean for a while
What it does not do
- Remove growth rooted in drywall paper or wood fibers
- Fix the moisture that caused the growth
- Remove dead spores and fragments, which can still irritate
- Keep water-damaged drywall from staying damp
The real goal is removal
Mold guidance from public health agencies emphasizes two things: fix the moisture and physically remove the growth. Killing mold is not the same as removing it, because dead mold and its fragments can still cause allergic reactions. On porous materials such as drywall, ceiling tile, carpet and insulation, the material is usually cut out and discarded rather than treated.
Bleach is mostly water. Sprayed on drywall, it adds moisture to a material that was already too wet, and the paper face can grow new mold as it dries. On wood, it bleaches the surface while hyphae remain below. Mixing bleach with ammonia or some other cleaners can produce toxic gases, which is another reason to avoid it as a default.
Handling a small area yourself
For a small patch on a hard or semi-hard surface, such as a window frame, a section of tile grout or a bit of painted trim, this approach is reasonable.
Protect yourself
Wear gloves, eye protection and an N95 respirator. Keep children and anyone with asthma out of the room.
Fix the water
Find out why the spot was wet. Without that, the growth returns.
Clean with detergent
Scrub with water and a household detergent, then rinse and dry thoroughly. Bag the rags and toss them.
Dry and watch
Run a fan or dehumidifier and check the spot again over the following weeks.
When to stop and get an assessment
- IfThe affected area is larger than roughly ten square feetFederal guidance suggests professional help at this size. Plan containment.
- IfGrowth is on drywall, insulation or carpetThose materials usually need to be removed, not cleaned.
- IfThe water came from sewage or floodwaterTreat it as contaminated and get help with cleanup.
- IfYou smell mold but cannot find itThe source is likely inside a wall, ceiling or crawlspace.
- IfAnyone in the home has asthma, allergies or a weakened immune systemAvoid doing the work yourself and talk with a doctor.
General information for Wheat Ridge, not a quote or professional advice. In an emergency, call 911.