DPC and plastered walls but very bad salt coming through!

[Phoenixfc7]

HI,

5 and a half months ago I had an injection dpc done to the entiure downstairs (the house is not lived in). In the kitchen I used the damp proof company to plaster the kitchen and it included taking an entire wall back to brick. I have salt coming through particularly on the wall that was taken back to brick. I have had the whole house plastered by another plasterer and no salt coming through. This plasterer used a chemical that surpresses salt and a waterproof sand and cement on the walls that went back to brick.

Ok the wall in question is double thick brick but no cavity. There was an issue with the gutter causing leak in the house on this wall that was sorted before the DPC and has been checked and is sound. The DPC company and the company backing the work through guarantee had a look and said it was just drying out. I am about to have a new kitchen put in in a weeks time! They agreed to coat with a salt retardent that should stop the salt. It hasnt, its worse! They are now asking their chemist department (!) here are the photo's. The DPC company said they put a waterproofer in the sand and cement but nothing to stop the salt in the original work. Surely if the sand and cement was waterproof it wouldnt be doing this??

The house is hundred years old, has double glazing and has just had the heating put on after 18 months standing empty. A dehumidifier is on more or less constant in the kitchen as per the instruction of the DPC company. Any help at all as to what is causing this or what needs to be done gratefully received.

Thanks

The pictures long range are the day they coated it with salt preventer (or whatever!) and the others taken today. There was less than a week between treatment and the close ups.

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• Phoenixfc7
• 19 Jan 2013
• 1

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• Phoenixfc7
• 19 Jan 2013
• 1

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• Phoenixfc7
• 19 Jan 2013
• 1

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• Phoenixfc7
• 19 Jan 2013
• 1

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• Phoenixfc7
• 19 Jan 2013
• 1

 

[roy c]

Sometimes when a damp or wet wall has had a chemical dpc put into it and it has been taken back to original (Brick or Stone) then re-rendered and plastered it will take a long time to actually "dry" out completely, and part of this drying out process "salts" will appear on the drying out area.All you have to do is brush these off till they stop appearing, dont decorate till the salts stop appearing. Also the company that did your dpc injection should of told you this and also if you are not happy with what has been done or what is happening ,get them back and show them your concerns and let them deal with it. You should get a gaurantee with work done by a reputable company...I used to give people a 30 year gaurantee but this was underwritten by the chemical company that I used to use . Which by the way was Sovereign Chemicals..I would also like to add that rising damp will only rise to 1200mm after that it is usually penetrating damp...What was the chemical that supresses salts called?

 

[Phoenixfc7]

I met the Dpc company at the house today. He said it was drying nicely?! I said about brushing off the salts he said yes. He basically said it just needs to dry out. I asked what he coated it with he said a salt retainer he said he couldn't remember sulphate something?? The dehumidifier is on constant and a low heat and good ventilation. Kitchen going in on 29th he said so long as the bit in the corner dries out then yes install it.

I also noticed that towards the top on the wall it's mockled and to run your hand over it feels uneven. I asked him about that he said caused by the towel although I don't believe this to be the case I fear the plaster maybe being pushed out?

 

[stevethespreader]

I met the Dpc company at the house today. He said it was drying nicely?! I said about brushing off the salts he said yes. He basically said it just needs to dry out. I asked what he coated it with he said a salt retainer he said he couldn't remember sulphate something?? The dehumidifier is on constant and a low heat and good ventilation. Kitchen going in on 29th he said so long as the bit in the corner dries out then yes install it.

I also noticed that towards the top on the wall it's mockled and to run your hand over it feels uneven. I asked him about that he said caused by the towel although I don't believe this to be the case I fear the plaster maybe being pushed out?

ive never heard of a salt retainer or anything else being applied over fresh skim, it looks like a bad plastering job so he may be right about the trowel making the mottle effect

 

[roy c]

I met the Dpc company at the house today. He said it was drying nicely?! I said about brushing off the salts he said yes. He basically said it just needs to dry out. I asked what he coated it with he said a salt retainer he said he couldn't remember sulphate something?? The dehumidifier is on constant and a low heat and good ventilation. Kitchen going in on 29th he said so long as the bit in the corner dries out then yes install it.

I also noticed that towards the top on the wall it's mockled and to run your hand over it feels uneven. I asked him about that he said caused by the towel although I don't believe this to be the case I fear the plaster maybe being pushed out?

ive never heard of a salt retainer or anything else being applied over fresh skim, it looks like a bad plastering job so he may be right about the trowel making the mottle effect

I agree with Steve on that one I haven't heard of that either, it looks like there was penertrating damp further up the wall, has the outside been repaired or patched up at all? It may have been plastered on a soaking wall and the salts have worked their way thru. Did the Dpc contractor give you a gaurantee on his work? Have a look outside and see if there is any where where water is getting in.

 

[dann09]

FWIW at this late date:

Sovereign do a Hey'K11 Anti-Sulphate - "that prevents movement of salts from background (ie brickwork ) to the newly applied render or tanking."

I just read that off their site, the stuff is a liquid, and no way should it be applied to the finish surface. Personally, i'd be doubtful that it, or any similar chemical wash, even when applied correctly, does much at all.

Sovereign's guarantee, by the way, merely guarantee's their chemicals, not the installation or the installer. Hence, they can wriggle out of just about any claim by citing a thousand and one things that are not purely the chemical.

For the bubbling in the pics to occur so soon after installation indicates that that is not a S&C, or S&L plus remedial finish, render. Did the OP actually see them mix and spread S&C? What is the skim?

 

[Micilin]

Looks like a mess to me. Painting wth a so called salt retainer.? I would like to know how the float coat was mixed and applied.The sand might have been full of salt. They might have added lime or plasticiser to the mix etc. No way should the OP have to treat these symptoms.There is a cause.