Can I pressure wash an old (over 10 years) shingle roof made of asphalt to get rid of moss?

Hi Jannet As a roofer I wouldn’t advise u to do this as it could make the roof a lot worse, I’d suggest scraping as much of the moss off as possible then get a fungal treatment sprayed on it

If the surface is asphalt. a light jet spray with detergent, should clean the asphalt Then it should be painted with two coats of white solar paint.

hmm, depending on the type of pressure washer.?it can be used. just try a small area first .stop and check the area? if its doing a good job and not damaging the roof. then carry on.then once finished use a fungal treatment. or the roofer can go to jannets house and check roof over then advise.or any photos

You should not presure wash any roof!!,scraping the moss off may help but do not treat cedar shingles with any treatment whatsoever,wrong roof covering for that particular location I’m afraid, Ian Marks