Mysterious stains found under old flooring: Is it mold and should I worry?
Stains uncovered during flooring removal often look suspicious and worrisome, leaving homeowners unsure whether to treat the subfloor or simply ignore it. This uncertainty prevents people from finishing their flooring replacement projects safely without second-guessing potential damage.
What people tried
Every workaround mentioned in the threads below. We haven’t tested any of them — and nobody here is claiming they worked.
- 1Vacuuming up the debris and laying new flooring directly over it
- 2Applying a stain-blocking primer like Kilz over the area before proceeding
- 3Ignoring the stain if it shows no odor or major structural warping
- 4covering the hole with another box while unsure how to proceed
In their words
Unedited, grouped by where they were said, most upvoted first within each place, each linked to the thread it came from.
“Any idea what it could be? I put the tile I took up in a box ready for the skip Tommorow and covered the hole with another box but unsure what it could be and a bit worried about lifting up the rest of the tiles under!”source ↗
Where this came up
People with this problem also raised
- 12How to get old unknown stains out of a rental carpet cheap
- 5How to get deep embedded dirt out of plush carpet
- 2Finding construction debris and mystery layers under old flooring
- 5How do I clean up a spilled drink on carpet so ants don't come?
- 4Why do my floors look dusty right after mopping?
- 4Why is my dry ceiling stain getting bigger?