Today's challenge - what might clean this staining off a rendered wall ???

Any ideas?

I've been asked to look at cleaning a number of walls with a red staining (see pics), the surface is rendered (K-Rend I'm told) and looks like the stain is bleeding through from below the surface.

Any ideas :

A) what it might be ? (salts/rust/pollution/weird algae??? ;-)

B) suggested approach to clean off?

I know K-rend is tricky to clean but any of you guys seen or treated this before?

I've not visited the site, as it's a distance away but can get any questions answered which might help?

Would like to do the job so any help appreciated!!

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This is how the big boys do it

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That doff system system being used is not cheap either

The staining is an algae, the best way to clean k-rend is to soft wash it, I use algoclear pro, great stuff, just a matter of brushing the solution on and leaving it for the rain to do the rest, usually takes a couple of weeks but can be quicker, depends on how bad it is. Easy work and good money.

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The staining is an algae, the best way to clean k-rend is to soft wash it, I use algoclear pro, great stuff, just a matter of brushing the solution on and leaving it for the rain to do the rest, usually takes a couple of weeks but can be quicker, depends on how bad it is. Easy work and good money.

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I wanted to buy algoclear but it was expensive so I went for patio magic, heard good reviews see for myself.../emoticons/wink.png

reading this thread gave an idea about doff steam cleaning might be niche market, I will contact them and ask how much

Algoclear pro works out about the same price as most other moss and algae killers you can buy in the hardware and garden stores, the pro version is high concentrate so 1 litre makes up 20-30 ltrs of solution, depending on what strength is needed. A gallon of most moss killer is about £15-£18 and is mixed 5-1 so makes 25 litres, not much difference.

The thing is with just washing the walls etc. you aren't killing the algae/moss/mould just removing the surface and it will come back very quick, I sound a bit like an algoclear rep!!:laugh:

Algoclear pro works out about the same price as most other moss and algae killers you can buy in the hardware and garden stores, the pro version is high concentrate so 1 litre makes up 20-30 ltrs of solution, depending on what strength is needed. A gallon of most moss killer is about £15-£18 and is mixed 5-1 so makes 25 litres, not much difference.The thing is with just washing the walls etc. you aren't killing the algae/moss/mould just removing the surface and it will come back very quick, I sound a bit like an algoclear rep!!:laugh:

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That is true 16 squid for 5 l ratio 1:4 so 5 l make 20

You must be on commission

Algoclear as far as I know is just 40% Didecyldimethylammonium Chloride http://mistralni.co.uk/products/didecyldimethylammonium-chloride

Algoclear as far as I know is just 40% Didecyldimethylammonium Chloride http://mistralni.co.uk/products/didecyldimethylammonium-chloride

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So mistralni product is better

Not tried it myself yet bit It's 50% not 40% and seems alot cheaper to buy than Algoclear pro branding.

Gotta agree about the algoclear (formally called moss go) it's bloody good stuff! Use it for my roof cleans. Remove the heavy moss then treat and leave...over a few months roof tiles return to their original condition. Even removes all that black staining from roofs. Prevents re growth for a few years too. Good stuff whatever it is /emoticons/smile.png

Far better than pressure washing!! Please never ever pressure wash a roof!! You'll take years off it's lifespan!! And the mess it creates is ridiculous!! soft wash all the way /emoticons/smile.png

To answer the original question it'll easily clean any render from all types of algae staining etc.. Just spray on and leave. (On a dry day obviously!)

If smurfs right and it's the same stuff then go for the cheaper, more concentrated option obviously....but I can't say for certain if it's identical..

Agree about pressure washing a roofs etc but using a doff, torik or other superheated water system I've forgotten what it's called now wont damage the substrate so to speak.

Oh silly me that what its called Therma Tech

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Torik

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Doff

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All three system are much the same thing but not to be confused with a hot pressure washer as can use superheated water far hotter so low pressure is all that is needed.