I was speaking with a "damp specialist" on the phone and he informed me that putting a membrane around the walls is the option to go for in a stone house.
He said the drill/injection method is not usually used (or maybe he said it's not effective - can't recall) in stone houses. Anyone know if this is true?
Also, if a membrane is placed around the wall, then wouldn't this mean that the damp is still coming up the wall but it's just not noticeable? If so, does this mean it could rot at the stonework (if it's still coming up)?
Does the membrane method remove the dampness from the air in the house? I would imagine the drill/injection method would prevent damp air as it stops the damp coming up the wall in the first place.
IME *rising* damp is rare, certainly in brick built houses. The whole wall is usually porous, so you can take your pick as to where it's coming in. The membrane method seemed a little expensive when I checked it out. The plastic itself isn't cheap and it has to be screwed every few inches, making it very labour intensive. I think the method plasterers use is to batten the wall, fix a wire mesh to the battens, and render the mesh. This allows air to travel behind the new surface and achieves the same result as the dimpled plastic method. I would talk to a few plasterers rather than a damp "expert".
I'm not by any means an expert, but I live in a stone house which used to be damp (still is in places).
injection won't work at all - it works (maybe) on brick walls because you drill a hole into the brick, and inject the liquid which then penetrates through the porous brick. Your stone isn't porous.
As for tanking (lining with a membrane on the inside), this can give you dry walls on the inside, but can also lead to the mortar degrading.
My approach was to eliminate as many of the sources of damp as possible (new gutters, fix render etc.), then make sure that all the rooms are adequately heated and ventilated. This has worked very well, except for a couple of odd spots.
Funny the way these "specialists" only suggest "cures" they sell.
neither would be particularly effective. The solution is to reinstate the system the house was probably built with and which has been removed or filled over time - the French Ditch.
"Dig a deep ditch around and then away from the building. Dig it as deep as you can without endangering the building. Then lay in a large vented drain pipe, and cover it with large clean stones to within 6" of the ground surface. Then lay a slate cover, like a roof, draining away from the footings, and turf over it. In this way any water in the ground will drain away leaving the cottage standing upon a dry island. Any water running down the wall will be drawn away from the footings and will enter the rubble fill and drain into the ditch. This technique is called a French ditch. When used properly, it cannot fail. Don?t be tempted to leave the stone fill as an uncovered rubble."
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Does the membrane method remove the dampness from the air in the
No. In older stone houses you need to keep an eye on condensation more than damp - they were built to be used with a lot of air exchange through chimneys with open fires and windows that leaked. Making them warm often means stopping air flow and you need to consider how to restore controlled but adequate ventilation.
I would imagine the drill/injection method would prevent damp
It has no effect on stone (or much else for that matter - but zero on stone).
Water doesn't come up the wall, "rising" damp doesn't - it does come through the wall though and can look as if it is wicking up. The French Ditch works (always) and is relatively simple.
Thanks for all the information and links Peter! I handn't heard of this technique before.
Is this French Ditch technique useable for a house which is a terraced house, or is it useable just with detached houses? As an "island" has to be built around the house.
It will almost certainly have been used on the building originally in some form or another. It can be perfectly effective on terraced houses - ideally all houses would have such drainage but even if only your house is done it will significantly reduce the problem (and if your neighbours have similar issues might persuade them to do the same!).
I take it from this he means something like NewLath (or the older Newtonite) lathing?
In a rubble filled cavity the injection fluid just runs down in the rubble.
Indeed, and as there is little ventilation the damp is trapped in there.
A wall sat on damp soil is going to be cooler than its surroundings, and much of what is labelled as "rising damp" is condensation on these cooler surfaces. I've lived in a house with two cellars one beneath the other, both backing onto soil, and even the lowest one dried out with a little heat and plenty of ventilation.
Then line the excavation with a geotextile - see Cormaic's pavingexpert site for the details. This will stop your drain from filling with silt.
However there is often a stone drain at the bottom of stone walls, you just need to flush the silt out of it and you may find your damp problems go away. In many houses I have seen there is a stone drain both inside and outside the foot of the wall.
If you are in a terrace you may well find that the stone drain at the foot of the wall has been blocked by a neighbour installing some service into his house, or simply filling the drain because he didn't know what it was for. In our terrace someone decided to build a sauna in the back of the cellar, and promptly flooded the upstream neighbour.
I also have a stone built house which has not been lived in for nearly 150 years, we have looked at this problem also, we have had many opinions experts and companies looking at the house. The census of opinion seems to be the walls that are below ground level have tanked with the membrane you mention, but around the house instead of any conventional DPC the most favoured method for stone seems to be, not sure of the technical name, but it is a wire that runs around the walls with a very low electrical current running through it, "don`t ask me how it works".
That's because it doesn't. The trick is the oldest in the dampfmeisters (very thick) book of tricks. In order to install the magic wire you have to clear all the rubbish from around the house, dig a trench and fill it with rubble (sound familiar?). If you simply stop at this stage the problem is solved - but to justify a vastly inflated fee you drape a bit of wire around the place.
Injection does not work in certain types of stone.
You have to keep the water out, which you can do by keeping the water away from your house with a french drain (not that this always works). Keep the water away from the bottom of the walls and it can't soak up.
I suggest you find an expert, check his refences, this is a nighmare, and easy to spend piles of cash for no effect.
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