Funny stuff happening on drying out wall.

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Chris Gamble
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Funny stuff happening on drying out wall.

Post by Chris Gamble » Wed Apr 18, 2018 4:35 pm

I have an internal gypsum plastered brick wall that was saturated with salt water resulting in efflorescance and furring.
The procedure with regards to rising damp or water ingress causing salts to appear is to -
Dry It (if possible and if not then resolve the water ingress)
Scrub it with a stiff Non Ferol Brush
Wash it with Distilled Water (no Chlorinated/minimum minerals)
Wash it with Muriatic Acid (more salt = stronger mix)
Wash it with Amonia (to neutralise acid)
Wash it with Distilled Water
Dry it
Seal l am struggling with what to seal it with?
I thought of an an alkali sealer or a salt resistant sealer (Permaguard or Dupont rtc) but these are designed for salt pool areas and are waterproof. This isn't suitable as l want to paint the surface.

Also l want to stop any water coming back through the sealer but allow vapour as, if there is any residual damp, l don't want it to osmose causing more salt crystals to appear on the surface.

Then again, if it is impermeable, l am worried about the salt crystals forming under the plaster in the air pores of the masonry.

I also want to prime the surface before any acrylic emulsion finish as a final barrier and thinking an anti-alkali primer might work?

Finally, if l do take the gypsum plaster off (salt water is notorious for damage to gypsum due to extrapolotion of the mineral salts) then l want to re-render then skim with anti salt cement render and finishing skim.
Is there any ready mix sealers, primers, cement render and plaster finishing products suitable as l don't have access to sharp sand. I can buy additives for the cement and sand but, as l say, sharp sand isn't available in my market.
I not sure if l can add anti salt additive to jointing plaster fot a top coat?
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Re: Funny stuff happening on drying out wall.

Post by moderator2 » Wed Apr 18, 2018 5:09 pm


Not a good idea to hijack an 8 year old thread. Here's a shiny new one just for you.
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Re: Funny stuff happening on drying out wall.

Post by wes56 » Wed Apr 18, 2018 5:27 pm

salt water, do you mean sea water or water thats brought salts to the surface?
any salted surface or surface showing damp has to be hacked off back to brickwork or stone and rendered with a 3:1 or 4:1 mix of sand and lime.use any old sand.

stay away from all those chemicals and never seal with chemicals or anything else.
emulsion is not a barrier its a water based decoration.

could you show photos of both sides of the wall or walls?
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