Salt penatrating walls - Help!

JasonH · Post by **JasonH** » Mon Apr 20, 2009 3:51 pm

Hello, when we moved into our house 2 years ago we were advised that sea salt came through the walls in a couple of places. (the house is 50 yards from the sea). I skimmed the walls and painted and thought that was that...

After a few months i noticed the paint was lifting of the walls, a couple of months later and the plaster was coming off too. It isn't damp, you can even taste the salt if you rub your finger through it. it's happening on the ground and first floor.

I was wondering, is there and thing I can paint over the top, a rubber based paint perhaps that will stop the salt from coming through before i re-emulsion them?

Any help much appreciated.

Jason H

thescruff · Post by **thescruff** » Mon Apr 20, 2009 3:58 pm

You need to seal the walls outside, not inside.

What material are the walls, and can we have a pic of the worst area.

JasonH · Post by **JasonH** » Mon Apr 20, 2009 4:04 pm

Hello,

The outside of the house has been covered with a pebbledash like substance. I believe this is a defensive mechnism because of the distance to the sea. It has then been painted.

The pebbledash had originally breached the damp course. I had a team in to sort this out last year. You can now see the damp course and holes were drilled around the entire building and a solution injected to prevent damp, but this hasn't stopped the salt problem. There is no evidense from outside, only on three of teh walls inside.

Any ideas?

thescruff · Post by **thescruff** » Mon Apr 20, 2009 4:20 pm

If you had damp problems before, then it could be the result of the walls drying out.

See what the pros have to say when they log on.

Post by **ultimatehandyman** » Mon Apr 20, 2009 4:37 pm

If a chemical damp proof course was installed last year, was the plaster knocked off and replaced on the inside of the property?

If it wasn't this could be the cause of your problem.

The salts could be rising out of the plaster, which is now drying out!

JasonH · Post by **JasonH** » Mon Apr 20, 2009 4:59 pm

Hello,

the plaster downstairs was knocked out in several places and where damp there was a damp problem. The salt problem which is mainly on the first floor wasn't touched (lack of cash). It is here where we have the problem.

If i were to knock the plaster of on the effected areas, is there any special solution i should put on the brick work before reapplying the plaster?

Thanks for all of your help.

thescruff · Post by **thescruff** » Mon Apr 20, 2009 6:46 pm

Has the cavity's been filled.

Whats the roof like, can driving rain get in/under the eaves.

Post by **ultimatehandyman** » Mon Apr 20, 2009 8:55 pm

If it upstairs then it is most likely penetrating damp. But I doubt if actual salt water is penetrating the walls, it is more than likely that rain is penetrating and causing the salts that are in the plaster to efflorescence.

Of course you could be correct and it could be salt water that is penetrating the walls, as I don't live near the coast I have not heard of it before.

I did once go into a loft in Blackpool once and there must of been two tonnes of sand up there, that had blown through the gaps in the slates.

JasonH · Post by **JasonH** » Tue Apr 21, 2009 10:03 am

Hello,

Thanks for your responses.

We don't have any issues when it rains, no water enters the house. I have been reliably informed that it is a salt penatrating problem, i just wondered if anyone was aware of a paint-like substance that i could use to stop the salt coming through?

thescruff · Post by **thescruff** » Tue Apr 21, 2009 10:54 am

Hi, What you are saying cannot happen in my mind, so I did some research and came up with "Hydroscopic salts" http://www.buildingpreservation.com/Use ... rs%20.html

What you do about it I've yet to find out, there may be something in the link, but let us know if you find something, in the meantime will keep looking.

thescruff · Post by **thescruff** » Tue Apr 21, 2009 11:09 am

Some quite good information here.

http://www.dampness-info.co.uk/tests.htm

stuart45 · Post by **stuart45** » Tue Apr 21, 2009 1:33 pm

If you live near the coast the salt air can penetrate cement mortar and weaken it ( mortar joints in brickwork may last less than 10 years). Sodium Chloride is also a hygroscopic salt which means that it can attract condensation into the plaster at a R/H of as low as 50%.
There are salt retarders which can be put into the render mix which help solve the problem.

JasonH · Post by **JasonH** » Fri Apr 24, 2009 9:52 am

Thanks for all of your help guy's. I found a product, it's called Triton Trimax1.

I add this to the water along with 4 parts sharp sand 1 part cement. I've to knock out the existing plaster and re-render, sounds simple enough