Block Paint Prep

Barry M

A customer wants a bid on washing and painting this block building. First thought was to just use my housewash to get rid of all the contaminants and some pressure to knock of loose paint and tell them there would probably be some scrapping and priming involved before painting, I plan to sub out the painting portion. I showed up to look at the building before bidding and see that it has some efflorescence or calcite problems. Now I'm not sure how to go about the cleaning process. What acid mix do I use for this problem and is it just a spot treatment thing or do I cover the entire building. As far as the paint prep is considered, do I have to go back after an acid bath and use my house mix and some pressure?

The customer thinks I can just blast the building with some pressure and then slap some paint on it but I want to do this right. I also don't want the problem coming back 6 months from now or the paint peeling off. I've read that using excessive water pressure on the efflorescence areas will only make them worse. How do I take care of this problem and do the prep at the same time. I haven't got much feedback on the PWing boards so thanks in advance for any replies.

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Barry Maddox - Midwest Pro Wash
Pressure Washing Indiana
Deck Cleaning

jordanski

hey man,
I got curious reading your question and found this:

doh! don't have enough posts to post a url from another site
google efflorescence, top page, 1st or 2nd entry, there's a link to several pages of treatment options, no problem, sorry I can't post the link
peace, jordan

Richard

There are different types of efflorescence. If you can't determine which kind you're dealing with, dry brush it off completely, then apply diluted hypochlorite or diluted caustic soda to the area while dry. Then rinse off with plain water. Allow the areas to dry completely, then prime and paint. This is somewhat of a normal solution to your problem. Good luck

MarvinWilleyJr

Had to search to see what this effloresence that you speak of was.... Found this, might be helpfull.....


Protecting Against Efflorescence
It is possible to protect porous building materials such as brick, tiles, concrete and paving against efflorescence by treated the material with an impregnating, hydro-phobic sealer.This is a sealer which repels water and will penetrate deeply enough into the material to keep water and dissolved salts well away from the surface.
Efflorescence can often be removed with diluted phosphoric acid (usually about 1 part acid to 10 parts water, but follow the directions on the bottle). Always test some of the acid solution on an inconspicuous area first to ensure it will not discolour the surface material. The acid dilution should then be neutralised with mild diluted detergent, and then be well rinsed with water.
The source of the water penetration should be addressed. If the water source is groundwater or faulty flashing the efflorescence may reappear, unless properly sealed.