Salt Neutraliser? Is it any cop?

Question

Hello,

Heavy rain in late 2013, coupled with soakaway failure resulted in a section of my home wall becoming very very wet. About 3m^2 of interior wall has suffered some "efflorescence" (salts lifting the paint) but the plaster is fundamentally in very good shape.

Drainage/soakaway is now fixed. External wall is thoroughly (waterproof) rendered and tanked to the footings and I am confident the it is as dry as it's going to be.

Now time to make good the interior.

Clearly the "belt and braces" approach will be to hack back and replace the affected interior plaster with a suitable system.

But I have discovered so-called "salt neutraliser" like

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which on the face of it might save a lot of hassle and mess.

Any opinions out there?

David

meow2222 · Accepted Answer

I've never used it but unless others have had good results with it I wouldn 't try it. I can see no way acetic acid or surfactant could stop effloresce nce. And the description is very weaselly. And it would a fair time to disc over it had failed to do the job, if you plaster over it. I very much suspe ct its snake oil.

Salts come out of masonry over time due to water evaporation. Its slow, and any plaster in the way does get ruined. That's how it works.

NT

Tim Watts · Answer

Agree.

The only way you will stop salts moving out is a) get them out completely in the first place (difficult) or b) convert them to something insoluable.

Can't see how acetic acid will do that apart from neutralising any lime present.

Tim Streater · Answer

You can't neutralise something that already neutral.

polygonum · Answer

Wondering if this comment in Wiki for Sodium acetate (which I imagine could form when acetic acid and sodium chloride are in close proximity) has any relevance:

Concrete longevity

Sodium acetate is used to mitigate water damage to concrete by acting as a concrete sealant, while also being environmentally benign and cheaper than the commonly-used epoxy alternative for sealing concrete against water permeation.

Tim Streater · Answer

Unlikely I'd have thought. Acetic is a very weak acid as, AIUI, are all the organic acids. The chloride in salt comes from hydrochloric, which is a strong mineral acid. BICBW as its 50 years and more since I did my chemy O-level.

john james · Answer

It means neutralise the effect of the salt, not neutralise in the acid/alkaline sense.

meow2222 · Answer

but how is that possible?

Weatherlawyer · Answer

Sulphate conditioners have been known for decades. Not that I know what they are but calcium sulphate is insoluble so whatever salt is coming out has to be turned back into the insoluble kind. Is it magnesium sulphate? That should have been treated at the brick kiln.

I would have thought that silicon surficants would make it impervious. Your best bet is to ask a salesman for the product details. Do they have a website?

Salt Neutraliser? Is it any cop?

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