How to get green film and algae off a wood deck before pressure washing
Stubborn green film, moss, and algae can cover decks and make them difficult to pressure wash without a pre-spray treatment. Moisture can also leave behind staining on older wood that needs low-risk fixes to look nicer.
What the numbers show
Counted from the threads quoted below. How we count
- This comes up 17.3× more often in r/CleaningTips 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.
- 1Pre-treating the surface with a mixture of vinegar and Dawn dish soap and letting it sit for about 15 minutes before pressure washing.Did this help you?
- 2Scrubbing with dish soap and a brushDid this help you?
- 3Using Bar Keepers Friend with a drill scrub attachmentDid this help you?
- 4Applying vinegarDid this help you?
- 5Using regular dish soapDid this help you?
- 6Vacuuming up wastewater using a wet vacDid 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.
“Looking for some advice on how to get rid of these horrible dirt stains from overflowing plant pots.”source ↗
“The water pools on the balcony because the balcony is not leveled properly.”source ↗
“No hose for a pressure washer”source ↗
“It has a green film everywhere with some moss or algae growing in spots. I'd like to make it easier to pressure wash - is there something good to pre-spray it with?”source ↗
“I have the same issue and could not find a solution after trying a pressure washer and then concrete cleaner.”source ↗
Where this came up
People with this problem also raised
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- 4How to clean an outdoor surface without ruining it
- 9How to clean dark roof stains without ruining the shingles