I had a knock at the door from a pavement cleaner saying the white spots on my pavement are mould. Is there any truth to this? I always assumed the spots were pigeon foul because I do see them flying around. I applied thick bleach on the spots and don't really see any effect, which suggests to me those are not mould. Any ideas?
White mould on pavement?
- Thread starter DiyNutJob
- Start date
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Man who said he cleans with special heat treatment that will not lift the sand like pressure washer.
Hmm, I just got a brilliant idea. Maybe I will burn the white spots with flame.
Maybe you should tell any cold calling 'tradesman' to sling their hook.
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Don't see why. If he shares his trade secrets, I think he's a good guy.
So some random guy touting for work knocks on your door, tells you the pavement is 'mouldy' (whatever that means) and you think he's just doing you a favour?
He has, though, giving me the needed prod. I never knew what those spots were and my assumption turned out wrong. Internet suggests those are lichen. I can see the spots are made from individual 1mm^2 oval shaped dots. Bleach had no effect. White vinegar turned the dots greenish. So, definitely biological.
Some of my neighbours got conned into paying some itinerant doorknocker to squirt their paving this summer.
Apart from washing out the sand, it looked brighter than the other houses for a couple of months, then got dirty again
Apart from washing out the sand, it looked brighter than the other houses for a couple of months, then got dirty again
Despite all the negativity towards the door knocker, he was right. Not exactly, but close enough. The white spots are biological and therefore must be lichens. This means bleach is effective, but the effect cannot be seen immediately. The white spots turn green if scrubbed with water and stiff nylon bristle brush. The scrubbing can remove the spots without too much effort after bleaching. It seems to take more effort if not bleached.
Previously I found abrasive "sanding" of the pavings with sand, water, and bleach worked, by pushing the mixture around using a broom. It is not until now did I understand why it worked.
Previously I found abrasive "sanding" of the pavings with sand, water, and bleach worked, by pushing the mixture around using a broom. It is not until now did I understand why it worked.
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Look like pigeon foul and unappealing. But it doesn't take much effort to remove the spots individually. So, I can remove some when I have nothing better to do. I can probably just brush them with bleach and let them die and disappear by themselves.
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