# Damp



## NickH01 (May 4, 2014)

Hi All.
The wall at the back of our house is partially cut into a hillside and is damp, our pre-purchase survey suggests the damp is penetrating through the wall from the ground it is cut into. 
One suggested treatment is to seal the internal face of the wall; my concern is that would 'trap' the water in the wall and lead to further problems (?)
It is a two storey house with approx. 2 metres cut into the ground with the bottom one metre or so showing the damp.
Has anyone had/got similar issues, can recommend any solutions? Or do we just simply clean and repaint as and when required?
Thanks.


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## olivefarmer (Oct 16, 2012)

Good luck

Unless you remove the problem(, drainage, excavation outside etc) then you are stuck with it. You could always tile which is the Spanish solution. That is often why the ground floor of a house is described as ripe for development but is actually just garage/storage. You would have thought by now that DPC and tanking would have been the norm in building


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## baldilocks (Mar 7, 2010)

As you have been told- it is normal in Spain. This applies even if the house is not cut into the hillside and is rising damp. One solution is to remove the plaster, coat with a PVA or bitumen sealer then re-plaster. We have been in our place six years now and are slowly getting ahead of the problem. If you get prolonged rains (as we did with the winter 2009/10) you may find water coming through exposed outer walls and the only solution there is to have the outside render hacked off and replaced with a water resistant one and then repaint with plastic paint (do not continue to use "cal").


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## snikpoh (Nov 19, 2007)

Another common 'solution' in Spain is to build another internal wall a few centimetres away from the existing one.

This creates a cavity through which damp can't penetrate. If necessary, you can put ventilation grills in this new wall to allow air flow behind it.


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## Lynn R (Feb 21, 2014)

I once lived in an 18th century weaver's cottage in England which was built into the hillside (built before damp proof courses existed, with flagstone floors) and the back wall of the ground floor was terribly damp. A short term solution was to build a false plasterboard partition wall just in front of the actual exterior wall, but long term nothing worked until the ground outside was excavated and the garden terraced.


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## Helenameva (Aug 15, 2014)

snikpoh said:


> Another common 'solution' in Spain is to build another internal wall a few centimetres away from the existing one.
> 
> This creates a cavity through which damp can't penetrate. If necessary, you can put ventilation grills in this new wall to allow air flow behind it.


Putting vents in the new wall will mean any nasty smells from the damp wall behind will go into the room. Much better to try to get a vent duct to an outside wall.


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## Chopera (Apr 22, 2013)

NickH01 said:


> Hi All.
> The wall at the back of our house is partially cut into a hillside and is damp, our pre-purchase survey suggests the damp is penetrating through the wall from the ground it is cut into.
> One suggested treatment is to seal the internal face of the wall; my concern is that would 'trap' the water in the wall and lead to further problems (?)
> It is a two storey house with approx. 2 metres cut into the ground with the bottom one metre or so showing the damp.
> ...


I'm not an expert but it sounds like your options are either to excavate (with proper drainage to channel water away from the house) or live with it the best you can. A false wall sounds the best way to live with the problem, maybe with a few air-bricks/vents on the external wall to let humidity out of the cavity.


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## virgil (May 3, 2012)

We live in an 18th century Cornish cottage which was extended in 2006.

The external soil level comes up to approx. 2m on the gable wall 

But, a 1m wall was built adjacent to that gable wall, the gable wall itself is a cavity wall - which was then 'tanked' internally.

So-far-so-good, I do, not so much worry about it, but give it a suspicious glance most weeks as I've seen what those-sort of conditions can do.

It obviously must have been done properly (watch this space!)

Tanking Wet or Damp Walls | Tanking Wet Walls | Damp Proofing | Air Gap Membranes | DIY Doctor


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## NickH01 (May 4, 2014)

Thank you all for your helpful suggestions.
My 'gut feeling' is to remove the existing plasterwork, re-plaster with a waterproofing solution (Sika1)added and then see what happens !?
I accept that the correct way would be to get the high ground excavated etc. I am trying to get quotes for this work.

Thanks again.


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## Alcalaina (Aug 6, 2010)

snikpoh said:


> Another common 'solution' in Spain is to build another internal wall a few centimetres away from the existing one.
> 
> This creates a cavity through which damp can't penetrate. If necessary, you can put ventilation grills in this new wall to allow air flow behind it.


That's very common here with old village houses which have been reformed. It makes the room a bit smaller but it seems to do the trick.


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## xgarb (May 6, 2011)

Old thread but I found some possible useful information.

It seems from this website that the English obsession with damp courses is nonsense (at least in old houses) and rather than coating the inside and outside of the house with waterproof coatings we should allow the house to 'breathe'.

Managing damp problems in old buildings


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## snikpoh (Nov 19, 2007)

xgarb said:


> Old thread but I found some possible useful information.
> 
> It seems from this website that the English obsession with damp courses is nonsense (at least in old houses) and rather than coating the inside and outside of the house with waterproof coatings we should allow the house to 'breathe'.
> 
> Managing damp problems in old buildings


Absolutely, this is why one is often advised to render with lime render (putty) rather than cement render.

And to paint with a breathable paint rather than 'plastic' paint.


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## tonymar (Jan 29, 2015)

When I was a builder here , damp was a real nightmare , 

Most things have already been suggested 

I have had quite good results in the past by 

1 Hack off old plaster and render to brickwork
2 make good any holes in wall with swimming pool adhesive 
3 paint with rubber roofing paint
4 render with a cement rich mortar 3 to 1 with water proofing adative
5 skim with swimming pool adhesive
6 paint with exterior quality paint

Or build a vented cavity wall as already mentioned , or tile the whole wall, or plastic t and g cladding with vents .

Hope you have some luck , damp is a big problem here , all for the sake of not fitting cheap damp courses in construction


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## baldilocks (Mar 7, 2010)

I think that much depends on the source of the damp. We had a damp problem on our back wall (very exposed), especially a few years ago when we had that very wet winter and it was caused simply by the rain coming through the wall. Solution was to put an impervious render on and plastic paint.

Another problem we had was caused by poorly installed a/c. The pipework to the external unit had been installed in the wrong manner being in a ∩ (an inverted 'U') shape, so that rain hitting the pipe ran down and into the wall where the pipe passed through. Having the pipe reshaped to a U shape so the the rain dripped off the lowest part, solved the problem. 

A lot of places around here, if they have an exposed wall either have it coated with foam insulation or some form of corrugated cladding (asbestos, plastic or iron) which not only keeps the rain off the wall but allows the wall to breathe by means of the channels in the cladding. It is a bit unsightly unless painted white to suit the rest of the building but it does seem to be effective.


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## tonymar (Jan 29, 2015)

snikpoh said:


> Absolutely, this is why one is often advised to render with lime render (putty) rather than cement render.
> 
> And to paint with a breathable paint rather than 'plastic' paint.


Yes its good to let the damp out instead of trapping it ( preferably externally ), I think that is why mono cap breathable type renders are so popular here , at least if there is no damp course the water can escape ( but some times salt deposits can occur )

Cheers Tony


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## virgil (May 3, 2012)

We had some awful horizontal rain last year in Cornwall. It penetrated the 3ft thick west-facing granite wall causing staining inside.

A Cornishman who knows his stuff recommended this product to me and I will be using it this summer to seal the external elevation.

Beeck BS Plus


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## gus-lopez (Jan 4, 2010)

olivefarmer said:


> Good luck
> 
> You would have thought by now that DPC and tanking would have been the norm in building


DPC was actually illegal due to the earthquake situation. I believe that it is ok now up in the North,N/west but still not allowable down here.


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