Incurable damp?

[DaveBrigg]

Our lounge wall has a damp problem. It's lime plastered and painted in breathable clay paint, but on a section 8ft wide and up to 3ft from the floor the paint is falling off, along with small patches of the top coat of plaster. This matches almost exactly with the raised floor of the room on the other side of the wall. It was a pantry, which for reasons unknown has a brick floor a foot and a half above all the other floor levels. To make things worse, on the wall in question there is a brick platform which increases the 'ground level' by another foot. The pantry floor is laid on sand, which presumably sits straight on the soil, as the outside walls have no foundations. I have already dug a French drain along the outside wall, but after nearly a year the problm remains.
As far as I can see, there are only three options.
a) Lower the floor level in the pantry and remove the brick platform. I don't think the CO would be too keen on this, and it would put the sink and window at shoulder height.
b) Keep repainting the affected area every couple of months (more often if we have visitors)
c) Buy the world's biggest flat screen TV and forget about the wall completely.

Any other ideas very gratefully received.

 

[middi]

From what you are describing DaveBrigg, this damp problem must have been there all the time that the internal floors have existed at the present level. The fact that there is no foundation and on sand it is a good thing for quick drainage and stability.

The fact that one internal wall is ( as you say) three feet higher which coincides with the damp line, one can only assume that capillary action is creating your damp problem. All things being equal of course, in the sense that there is no slow leaky pipes or re-diverted ground drains etc...

I cannot see you curing this problem as long as you have differentials in ground levels.

I would most certainly speak to your CO first.

 

[Nemesis]

If this is bad enough to cause failing plaster than possibly one solution to consider would be to internally line the wall with a membrane and place a false wall over that. Historic fabric remains and you won't get paint dropping off.

Clearly it's not so bad that you would need any sort of sump and pump, but some ventilation to help dissipate the damp.

 

[rbirkby]

a) Lower the floor level in the pantry and remove the brick platform. I don't think the CO would be too keen on this, and it would put the sink and window at shoulder height.

In my experience, conservation officers aren't against doing work on a listed property. They would much rather you to change the structure of the property than have it fall down.

 

[Matt Green]

Penetrating damp. That part of the wall is earth-retaining, and short of lining it or the dramatic reduction of the pantry floor level, it's likely to remain as is.

What was the purpose of the lounge room originally? Storage?


Matt

 

[Mark]

can you lift the floor in the pantry which is against this wall, put a barrier down - leaving an air gap - then replace the floor above.

I'm thinking of that corrugated stuff that I've seen for use on external situations where the ground level is high on the outside of the wall.

 

[Nemesis]

Newton membrane?

It would be less damaging to do it on the room side.

 

[Mark]

would it?

digging out soil and tehn replacing the brick seem better to me than fixing things across the whole of the main room wall.

 

[Nemesis]

Listed building... the membrane and inner wall would be fairly reversible, and not disturb 'historic fabric'.

Easier also maybe?

 

[middi]

It must be worth a try by installing a membrane against the face of the retaining wall. If it does work to an acceptable standard it will overcome the problem of the window line. Also not much interference with the original fabric and easily reversable as Nem. suggested.

 

[Nemesis]

The plaster falling off is not good, but I do wonder if lime paint rather than clay might be a little more robust in this situation.

I haven't really delved into what's in clay paint, but lime has a reaction which isn't the same as simply drying.

However, in a room you live in you really don't want damp of any sort visible really.

 

[DaveBrigg]

Thanks for the helpful comments. I'll try to add a couple of pictures to make it clearer, but it looks like any improvement is going to come at the cost of a certain amount of upheaval.