Correct treatment for a damp inglenook

[SamH]

The external ground level against one wall of our c18 Cotswold stone house is around 5'. The large inglenook on the other side of the wall is damp. We recently removed unsightly concrete render from inside the inglenook (sides and floor) to reveal red brick on the walls (again pointed with cement) and orginal flags on the floor. The inglenook was subsequently plastered with multi-finish (We asked for lime and are now in dispute with the plasterer but that is another story! He says it makes little or no difference given what's underneath). Alcoves on either side of the inglenook have air bricks (not sure why as they are well below the exterior ground level) and the multi-finish here is totally dry.

We are planning to install a wood-burning stove but am at a loss as to how to prepare the inglenook.

Do we try to banish the damp with the use of a membrane (Newton or similar) or will the stove and the increased air circulation solve the problem for us. Will the stove gently dry the multi-finish or crack it? Would the result be the same with lime or would lime be an appropriate finish for this combination of damp and heat?

So many questions, too little experience. Any and all advice gratefully recieved.

Thankyou!

 

[chuckey]

Modern plasters do not take kindly to prolonged damp. They literally decay and crumble and fall away (hence the render). What you really should do is to dig out the back of the wall and install some vertical damproof membrane and a french drain to try and reduce the level of the water table. I have had to do this with my cottage. The air bricks are trying to dry the wall out by evaporatinng the water into the room, so you will have condensation problems. The fire will accelerate the drying effect, but as the water is being constantly topped up by the ground water from out side its like p**ing into an ocean, you know that its working but you can't see the effect.
What your builder should have done before he plastered was to tank the area, i.e. to make it totally watertight. Then the plaster would have a decent life and the room and house would have less water vapour to contend with.
Frank

 

[SamH]

Thanks Frank!
Unfortunately we can't introduce a french drain as the land belongs to a pub next door and is used as a path to the entrance of their premises. We'll have to tackle this from the inside. Looks like we may have to remove the multi finish (and bricks?) and reinstate the render.
Sam

 

[Penners]

The type of Newton membrane that I've seen just had dimples in it. I'm not convinced that this is the best solution for your problem.

I know that the soil outside the chimney is a path on the pub's land, but is there any chance that they would let you do a bit of digging, provided you reinstated afterwards?

If so, I would be inclined to dig the narrowest trench possible around the chimney wall, to enable you to slide down a vertically corrugated membrane against the wall. Then backfill. This would prevent water ingress into the stonework from the soil 'leaning' on the chimney, but the corrugations would allow air to get to the wall and ventilate it.

Once you had completed the work, the only impact on the pub's path would be lots of small holes against your wall, where the top of the corrugation trenches were visible.

 

[FamilyWiggs]

Pennervs - good idea. Had been thinking of something similar for the two walls of my subterranean dining room.

However, without a drain installed at the bottom of the trench, wouldn't this just lower the water table and the water would then flow under the bottom of the membrane (meaning the base of the wall or the floor would be even wetter) or around the ends of the wall (which in my case it can't because there aren't any ends (if you see what I mean)

 

[Penners]

It's difficult to say, FW, without knowing just how much damp there is in the ground. The corrugations ought to allow modest damp to be carried away by ventilation, but these things are always "suck it and see".

Of course some form of drainage at the bottom of the membrane would be an extra insurance policy, if it's a practicable proposition.