Why is there condensation and damp spots on walls only on laundry days?
Unvented indoor drying releases enough moisture to cause localized condensation and damp patches in specific rooms. This traps excess humidity against cold surfaces, preventing normal evaporation until the washing cycle stops and the space dries out over the next day.
What the numbers show
Counted from the threads quoted below. How we count
- People have been saying this in most months since September 2026.
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.
- 1Calling a plumber or professional to inspect the walls and find potential leaksDid this help you?
- 2Checking if there is an issue with the dryer vent or ducting inside the wallDid this help you?
- 3Leaving the bathroom door openDid this help you?
- 4Setting up a stand fan to push airflow out into the apartmentDid this help you?
- 5Using a portable dehumidifierDid this help you?
- 6Squeegeeing walls and tub after showersDid this help you?
- 7Hanging towels outside the bathroomDid this help you?
- 8having the outside brick wall repointed and sealed with weather shieldDid this help you?
- 9having the window sealed around the outside with new sealantDid this help you?
- 10having roofers inspect the roof above the windowDid this help you?
- 11taking a slow moving video around the open window with a selfie stick to check the sealDid this help you?
- 12Drying clothes indoors on a rackDid 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.
“Moisture coming through wall on laundry day?”source ↗
“the biggest clue is that we primarily notice the damp spots on laundry days, when we’re washing and drying several loads throughout the day.”source ↗
“the spots also seem to follow a pretty consistent pattern: they become damp while we’re doing laundry, then dry out by the following day once we’re done.”source ↗
“we've had damp around a particular window for years, we've had the outside brick wall repointed and sealed with weather shield and had the window sealed around outside with new sealant, we've also had two roofers round to look at the above flat roof and they can't see anything amiss or wrong with the roof, is this a window issue?”source ↗
“Ciao, long story short I live in the Netherlands in a studio with very little to non ventilation, very humid and with mould problems. What contributes to the mould is ofc cooking, showering, and drying my clothes on the rack. I am looking for the best dehumidifier budget up to 250euros, ideally less, considering that the studio is only 25m2.”source ↗
“I've noticed the room is prone to a little bit of damp.”source ↗
“there's occasionally condensation on the inside in the mornings but only in this one room.”source ↗
“In my apartment, our bathroom has no working vent/fan to help prevent mold.”source ↗
“Must be renter friendly, and there are no windows in the bathroom either.”source ↗
“Definitely doing the doors open and fan in the doorway already, but it still gets moldy in there no matter how much I clean/try and prevent!”source ↗
Where this came up
People with this problem also raised
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- 8Why are my metal floor vents sweating and growing mold?
- 2Why is condensation causing mold and ruining my appliances?
- 5How to dry out a soggy crawlspace
- 23Why is my AC not lowering indoor humidity?