Removing Lichen from House walls

[minermick]

`IF` the weather holds up I intend to paint the outside of my house in the next few weeks but i`m unsure what to use to remove the green lichen streaks in some places (I live in cornwall and this always a problem). Would a solution of diluted household bleach do the job or should I go for a proprietary remover of some kind? Which is best?
I had it painted 4 years ago and the guy that did it removed the lichen at the time but I dont know what he used.

 

[ic1927]

The best stuff I've used is "Bond it moss stop". Mix it one part with three parts water, brush or roll it on, leave for 48 hours then you can either go straight on with the masonry paint or do as I do and rinse with a hose and clean off the green stuff with a hard brush. It comes back clean, removes it all.

 

[handypainter]

Are you sure its lichen? Sounds more like algae to me, in which case household bleach would be perfect. A mixture up to 50/50 bleach and water would be ideal.

I use a garden sprayer to apply it, hard brush to scrub if required, and a pressure washer or hose sprayer to rinse off. Don't allow the bleach solution to dry before rinsing though, but do leave it on long enough to work

 

[minermick]

Yes I think you are right, its more like algae. Thanks for the replies guys.

 

[maltaron]

I have just had my bungalow in Cornwall painted. My decorators used ordinary supermarket general purpose cleaner in warm water, brushed mostly with a stiff broom and a scrubbing brush on stubborn stuff. The secret is to hose down to remove all traces of soap before painting.

 

[handypainter]

General purpose cleaner is fine for grubby wallls, but does not kill algae or fungus. Occasionally we will add bleach to a degreaser on problem areas.

Also, you should ensure a fungicide is applied prior to painting to stop the remaining spores from growing under the paint film.