Various damp problems w/ solid walls

10 Jan 2006
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United Kingdom
Hi there, I have acouple of damp related questions which I'm hoping some of you experts might be able to help with.

Fisrt of all, the house is an early 1800's end terrace with 400-600mm solid stone walls, rendered (slightly damaged) on the outside and on a slope, so the back of the house (kitchen) is actually about 1m below street level. The house does not have a damp proof course, as far as I'm aware.

1. We are experiencing damp in the kitchen in the "underground" bit of the house, both through the floor (salty deposits coming up through the orignal quarry tiles) and similar salty deposits and flakey paint on the walls under the pavement. What can be done to prevent the damp coming in since we're below ground level, an injection DPC surely wouldn't work from the inside and nothing would be achieved by putting a chemical DPC in from the outside above the pavement which is about 1/3 of the way up the wall!
TO solve the problem with the floor, am I right in thinking we can just put a waterproof membrane over the top of the quarry tiles and put self-levelling conctrete over the membrane, or would the tiles need to be dug up first before putting the membrane down?

2. The gable end of the house, including the chimney stack and also some areas of the front of the house has some quite large cracks in the render; this results in the inside walls (both ground and first floor) becoming damp and peeling in wet weather.
Short of re-rendering the whole house (quoted £3500 to do this) what would you suggets can be done to stop the penertative damp - try and repair the render on the outside somehow, or put some kind of non-permiable paint on the inside and repaint on top?

3. Finally(!) we have a small cellar, which unsurprisingly is damp also and one of the joists under the floor at the front of the house has damp rot. After replacing the joist would introducing some ventilation into the cellar by putting a extractor/recirirculating fans in the wall up to the pavement be sufficient in your opinion or would the only real solution be to tank the cellar by putting a waterproof sealant/membrant on the floor ad up the walls as well? We are currently experiencing damp coming through the slabs on the floor when the dehumidifier is left off so I'm guessing that both ventilation and tanking would have to take place in order to stop the damp.

We've had two guys come round already, one says to solve the damp in the main part of the house, just re-render as it's probably penetrative damp through the cracks in the render. The other suggested taking off the plaster in the downstairs and putting a DPC in, but I'm struggling to see how this will help with the underground, but of the house and also the fact we have solid walls, isn't that a problem?

Sorry for the long post, but I'm looking forwrad to hearing some of your suggestions as to what sounds like the best plan of action!

Many thanks,
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im a bit wrecked to read all the post but will do later but what i would ask is what is different from 200 years ago, here lies the problem ;)
Hiya, thanks for replying although I'm a bit stuck with your cryptic clues... :confused:

Loads of things have changed in the house in the past 200 years, UPVC double glazing has been put in and one of the fireplaces blocked up for a start. That and the fact we live less 200m from the beach and no doubt the water table has risen in 200 years so generally the land on the coast is more saturated than is was then...

Any help in solving the problem, or suggestions as what can be done to prevent the damp (DPC or rendering?)
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Ok lets see... your property is 200 years old, so when it was built plumbing and electricity were science fiction.. so was "waterproofing". So your fighting a battle you may never win without a large cost.

so, 1) A dpc in a solid wall is pointless unless you continue through the wall and tie in with a dpm below the flooring. So yes bury the tiles below a damp proof membrane or dig them up, will depend if you can loose the headroom. You may be better off checking the floor first by lifting a tile diging a small hole through whatever you find below, old houses sometimes had little to no ground floor, you may only find 1" of concrete.
I would recomend you put in a perforated drain in the ground by the earth retaining part of the building.
Water will move through the easiest route thus the cracks in the concrete floor slab or the walls.

2) You need to stop the cause of the walls cracking first, or youll spend £3500 on rendering only to have it crack again in a couple of years.

3) Ventilation in cellar will help alot, mostly cellars are very damp/cold spaces anyways so unless you plan to use it as habitable area you might as well spend your money on other things. But if you do wish to use it then tanking the walls and membrane under flooring will assist in damp reduction.

Get more so called experts in after about 5-6 you should have a good idea on what price and areas of work that are vital. Also if cracks in walls are significant get a Structural Eningeer in to give some advice.

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