Page 2 of 2

Re: Pressure washing

Posted: Tue Mar 16, 2010 8:22 pm
by Colin
Painting over the Algae, dead or alive, means that it is between the surface and the paint therefore the paint ain't going to stick. If the Algae is still alive it will carry on growing - even under the paint, and the fungicide in the paint is only there to kill any fungal spores that just happen to land on the wet paint, its not strong enough to kill whats underneath.
I've done a few jobs where the previous painters couldn't be arsed to clean off the lichens, which carry on growing. With a nice protective "hat" of paint on, they are hard to scrape off. :angry:

Re: Pressure washing

Posted: Tue Mar 16, 2010 9:06 pm
by Peterpainter
I have never painted over algae like i said i alway clean off algae with fungicidal wash/brush. just dont pressure wash the entire building. Only set up on my own last year and did two external render jobs one was so bad I had it blasted first. I guess I will be off to buy a pressure washer before/if the summer kicks in. Thanks.

Re: Pressure washing

Posted: Wed Apr 21, 2010 8:27 am
by jerry3571
I use a third bleach to water for algae and mould. I do pressure wash off but on Masonry it has been said that using a pressure washer almost injects water in to the substrate causing future problems. Also if Salts are not removed prior then the water can disolve and then be re-absorbed back in to the wall or bring out deeper salts.
I don't know :001_unsure:

Cheers Jerry

Re: Pressure washing

Posted: Sat Apr 24, 2010 3:33 pm
by Peterpainter
The whole design of a cavity wall is that water can saturate and pass through the outer skin and run down the cavity/wall tie, so I dont think moisture can get trapped, unless it is a really old house cavity walls have been around for a hundred years now. I know masonry paint is breathable anyway, so as long as the surface is dry then the substrate can continue drying out after its painted.

Re: Pressure washing

Posted: Mon Apr 26, 2010 9:15 pm
by Peterpainter
Some good in info on pressure washers if anyone is looking, especially the motors bit: http://www.diyfaq.org.uk/electrical/pre ... er_faq.htm

Re: Pressure washing

Posted: Thu Jun 28, 2012 4:34 am
by Squeen
Word of warning,we have had 3 karchrs ,every one has had serious faults, they are made for a very light domestic market.
Tired of all the hassle I bought a Kranzle, 2 years of heavy use still brilliant.