White fungus growing on crawl space wood
Unexpected fungal growth or mycelium in a crawl space or basement points to moisture issues that cause wood rot and compromise structural integrity. Discovering rotted sections of structural wood like band boards requires immediate assessment and repair to prevent further damage.
What the numbers show
Counted from the threads quoted below. How we count
- The most recent one is from September 2026.
- This comes up 22.4× more often in r/HomeMaintenance 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.
- 1scraping it off the surfaceDid this help you?
- 2buying a moisture meterDid this help you?
- 3putting a dehumidifier down thereDid this help you?
- 4having a professional come and assess the full situationDid this help you?
- 5Using temporary wood supports and jacks to hold up the structure until it can be professionally evaluatedDid this help you?
- 6removing the caulkingDid this help you?
- 7pulling the piece of trim off to check the extent of the rotDid 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.
“Went down into my crawl space today and noticed white stuff everywhere that wasn't there before.”source ↗
“I noticed some mushrooms were growing in between the door frame this morning. I've never seen this happen before anytime I've been here.”source ↗
“damp wood and mushrooms means rot already set in man. that dark frame against the brick is a classic spot for water to sneak in especially with the humidity lately.”source ↗
“I was replacing the trim in the back of my house from water damage wood rot, and I noticed that the band board is water rotted about a 2 to 3 foot section”source ↗
Where this came up
People with this problem also raised
- 8How to find and handle hidden mold behind walls
- 6Are these bugs termites or carpenter ants eating my wood?
- 3What are these stains and damage on my attic roof sheathing?
- 3Is this mold or a water leak, and do I need to call someone?
- 25How to clean mold on furniture after rain gets inside
- 3How to tell if mold is hiding after a roof leak