How to clean mold on drywall or know when to cut it out
Surface sprays only treat top-layer growth, leaving hidden spores inside soaked walls to spread further. Trying to guess whether to patch or cut out the drywall stops people from stopping the damage before it ruins the structure.
What the numbers show
Counted from the threads quoted below. How we count
- The most recent one is from October 2026.
- This comes up 10.8× more often in r/HomeImprovement than across the site as a whole.
What people tried
Every workaround mentioned in the threads below. We haven’t tested any of them — and nobody here is claiming they worked.
Found another way around this?
Share your steps and trade-offs so fellow engineers don't have to reinvent the wheel. No account required.
- 1Treating the area with mold removal spray and painting over itDid this help you?
- 2Cutting out the affected drywall and replacing itDid this help you?
- 3Hiring multiple water damage companies for inspectionsDid this help you?
- 4Consulting window installation companiesDid this help you?
- 5hiding in the room wearing a maskDid this help you?
- 6relying on management to spray and dry the area with a blower fanDid this help you?
- 7Cleaning the ceiling with a vinegar mixtureDid this help you?
- 8Replacing the shower curtainDid this help you?
- 9Caulking the cracksDid this help you?
- 10Waiting for the ceiling to dry out by itself as advised by building managementDid this help you?
- 11Painting over water stains if they eventually appearDid this help you?
- 12Buying a moisture meter independently to check moisture levelsDid this help you?
- 13Leaving the wall open and hiring separate drywall or mold remediation contractorsDid this help you?
- 14Scrubbing with hot soap and waterDid this help you?
- 15Spraying with white distilled vinegar and letting it sitDid this help you?
- 16Bleaching the entire roomDid this help you?
- 17Using a dehumidifier and opening windows for ventilationDid this help you?
- 18Shop vacuuming the water and letting the area dryDid this help you?
- 19Covering open wall areas with thick plastic sheeting and tapeDid this help you?
- 20Wearing personal protective equipment like N95 masks and hazmat suits to DIY the cleanupDid this help you?
- 21Removing damaged drywall, insulation, and trim independently and using fans, dehumidifiers, and mold cleanersDid this help you?
- 22Getting a second opinion from another HVAC companyDid this help you?
- 23Spraying mold killer as part of regular maintenanceDid this help you?
- 24Installing a UV light or air purifier like a REME HALODid this help you?
- 25Replacing the entire plenumDid this help you?
- 26searching for the water source or bad sealing where the addition meets the houseDid this help you?
- 27using mold remediation spray such as Mold ArmorDid this help you?
- 28measuring room humidity with a hygrometer and using a dehumidifierDid this help you?
- 29Scrubbing and cleaning mildewed foundation wallsDid this help you?
- 30Gluing XPS insulation directly to the block foundation before reframingDid this help you?
In their words
Unedited, grouped by where they were said, most upvoted first within each place, each linked to the thread it came from.
“Please help! How do I clean this? Need all the tips..please suggest budget friendly solutions . Also , cannot abandon ship even if it's dangerous, just cannot afford to at present.”source ↗
“What can be done on an immediate basis for this? I am not aware of how to clean this. Google is telling me I need professional help and AI agents are giving me home remedies.”source ↗
“No it's gotten like this in the last year.”source ↗
“The right wall has been open framing like this since I've moved in - no vapor barrier and the block foundation has been open and exposed.”source ↗
“What do I need to do in terms of scrubbing/cleaning the left mildewy wall to properly prep it for finishing properly?”source ↗
“Unsure how big of a deal this is and if mold spray will be fine”source ↗
“Should I cut a hole right where the black patch is or is a little below okay?”source ↗
“does this look like a DIY cleanup with a tyvek and N95 or should I outsource to a mold company?”source ↗
“i can’t imagine any company will tell me if i can/what it will take to mitigate this.”source ↗
“i stopped messing with it in due to not having a clue about what I’m doing.”source ↗
“I couldn’t afford it and would be hazmatting up and seeing what I could do.”source ↗
“Plumbers cut this piece of dry wall off, fixed the leak, and patched it up using the same moldy piece of dry wall. There was black mold behind here and on the dry wall itself.”source ↗
“my concern is that even though there are no visible water stains in our ceiling we dont want to live with mold.”source ↗
“I have spoken with the admin and engineering of the condo yet their only solution would be to let dry and if ever wet stains appear they will just paint over it.”source ↗
“I am not sure what to do next, should i just take their advise and just wait for it to dry? will it even dry by itself and no mold will grow?”source ↗
“Yeah already talked with them, their only solution is to paint over if there are visible stains. Yeah ill try to buy a moisture meter this week.”source ↗
“I am having water stains on my drywall and no one can tell me where they are coming from.”source ↗
“The water damage companies we’ve hired to come out are all over the place (some saying our walls are soaked, others saying they are dry, some saying it’s an active leak, some saying it’s just humidity and condensation).”source ↗
“We have no idea what to do.”source ↗
“they need to figure out where the water is coming from first, probably bad sealing where the addition meets the house”source ↗
“There is mold in my HVAC closet, the closet in the living room and there’s about a foot of mold all around the bottom of the closet.”source ↗
“when I informed my management. They told me that usually when the wall is soggy then they take out the drywall but if the wall isn’t soft to touch, then they can just use a specialized cleaner”source ↗
“I’m currently hiding in my room with a mask.”source ↗
“the room is filling with what seems to be black mold -- its been spreading exponentially the past few weeks.”source ↗
“The tech identified biological growth (I know this is code for mold when you can't legally say that) within the supply plenum, pics attached.”source ↗
“They quoted me on either replacing the entire plenum (> $2000) or installing a REME HALO ($1275, or I can upgrade my membership plan from ~$240/year to $612/year to cover any potential future bulb/catalyst replacements...)”source ↗
“I guess im just worried about the possibility of mold already inside the ceiling and am unsure if caulking would fix the problem long term.”source ↗
Where this came up
People with this problem also raised
- 18How to get rid of severe black mold on bathroom grout
- 4Dealing with severe mold in a rental when management won't act
- 14How to clean mold under water damaged flooring without DIY experience
- 26How to clean mold on furniture after rain gets inside
- 7Mold on things from a storage unit
- 2White fuzzy mold growing on artificial turf