Red coming out through plaster

almighty1

Hi,

On our south facing gable end, there is red coming out through the plaster and it looks really crap. We used a white plaster with a nap finish but this is the only area that exhibits this problem. House and plastering is around 7-8 years old

I'm thinking of lightly powerhosing it but would like some other opinions.

Some pics.

slimjimmc

Most web searches point to it being an algae or fungus which can be killed off with a dilute bleach solution then washed down after a while (don't know how long). Test on an inconspicuous area first.

North West

+ 1 for slimjimmc. Leave solution on for 24 hrs then power wash
Nw

wayoutwest

I may be totally wrong,but the stains seem to be streaking out from particular points suggesting that something is leeching out.from within or behind....iron oxide?

gugsy

Its red algea that can be cleaned by using "mosgo red and green algea killer" you can buy for around €30. spray on with napsack sprayer leave for two dry days to allow the mosgo to kill algea and powerhose off (this will remove the roots). Then paint over if required.

regards
Paint shop assistant

almighty1

Thanks guys I 1/4 bleached the whole lot and it has certainly drastically faded. I never got around to powerwashing it.

Perhaps I'll give it a few more weeks and apply one more covering of 1/4 bleach and then powerhose afterwards.

Will post some pics afterwards.

Thanks again.