Dreaded rising damp in old stone house - advice please

[EastMids2]

We've finally realised the dream and retired to Somerset, buying a hamstone cottage built in 1839. Full structural survey highlighted areas of damp on ground floor and in a 60's extension in particular, but it wasn't until the carpets came up, old Marley tiles removed etc that the true extent became apparent. We now have damp stains under emulsion paint, blown plaster and black mould creeping up walls.

I think the problem is that flagstones, concrete paths etc outside are at a higher level than the property (not sure by how much or if there are damp courses, maybe not).

Does anyone have experience of solving this issue - I appreciate old houses are never like the modern ones I've lived in for years and need to breathe etc, but feel very downcast that the damp is this bad and worried it will cost more than we can afford to remedy, even if that's possible.

Partner is saying just put property back on the market and cut our losses. I'd like to at least try and sort things out and give the cottage another chance to "live" again - or am I just being romantic rather than realistic?

That's almost certainly why, if the surrounding areas are higher than the existing DPC, then the water will permeate and start rising up your walls. My understanding is that you'd need to dig out a 'trench' surrounding the property to below that level and stick in some coarse pebbles to act as a French drain, which should allow the water near the house to drain away.

Also, what sort of interior finish is it? You often get problems if modern materials are used in older houses - the walls need to breathe so need specific plaster and paint to prevent bubbling and moulding.

Thank you for prompt response LBOCS2 - outside definitely higher and garden slopes down so rainwater naturally runs down. The extension (1960's rendered outside) is where damp is worst. There is a metal grill around the outside which I lifted and it's a glazed earthenware gulley - no obvious drainage holes - leading to a normal drain. Given the age of this extension I suspect it's modern plaster and definitely ordinary emulsion (they left the same colour paint tins in shed!).

This French drain sounds a good start and I've just arranged for a specialist damp company to come out next week.

Have also seen an earlier thread about rising damp and note the pitfalls about pressure selling for dpc's and chemical injection treatment. Structural seems the way to go and just hope it can be remedied to a satisfactory degree without bankrupting us in old age!

Has anyone done this French drain process to give a very rough idea of cost, please?

Anyone out there with rising damp issues?

I hope the specialist company does not sell chemical injections or magic render. Neither will work, especially on stone walls.

If the 1960's extension is damp, there is something badly wrong, as it will (should) have an effective DPC, good gutters and downpipes. There may be a leak.

You might have wet solid floors with no DPM. It is possible, though wearisome, to dig them up and relay properly.

Lowering the ground level outside is your first step. If you are on a hill, you need to intercept any water that runs towards your home, and lead it away downhill round or past the house.

Dh did a French drain for one wall of our old house. He dug it out himself so it was just the cost of some bags of pebbles. It sounds like a bigger deal for you if there are concrete and flags in the way, but still not a terribly big job.

I definitely recommend this book - Old House Handbook: A Practical Guide to Care and Repair Hardcover – 23 Oct 2008
by Roger Hunt (Author), Marianne Suhr (Author)

Old houses with single skin stone walls or single skin brick were built to deal with the ingress water completely differently to modern houses. The problem will probably be a combination of the high level of the outer wall and possibly a change to the flooring internally? The 60s extension is another matter as it should have been built with a DPC as PigletJohn said.

Stone wall houses are designed for the walls themselves to soak up some water over the winter but then for it to breathe back out over the dryer months. If at some point your house has been given a concrete floor this will stop the damp breathing back out of the walls and it will start to cause what looks like rising damp.

Have a read of this article too - it may help explain. www.davidkinsey.co.uk/pages/damp.php we are struggling with a similar problem.

Whatever you do, don't let a normal builder touch your older cottage - you need a heritage builder or a builder familiar with lime mortars/lime render etc. Concrete in older houses is a nightmare!

Also recommend joining SPAB as they have a wealth of knowledge!

This is a guidance note on French drains www.ihbc.org.uk/guidance_notes/docs/tech_papers/French%20Drains.htm

Chemical DPC do not work and never ever should be used in a stone cottage.

Have the walls been re plastered in gypsum plaster?

Very helpful info - thank you all. I've noted the recommended reading/links and will follow up.

Cottage is built from local hamstone and walls approx. 16 inches thick. The blown plaster in main house looks "old" and has been re-painted many times by the look of it. Some white painted brick walls are discoloured and the tinge has returned after two coats of good quality paint. I'm not so bothered about this as the fresh black mould and wet carpet in extension.

The extension walls are much more narrow, maybe breeze blocks or brick - it's hard to tell under the render. There are obviously two different problems here.

Would a property of this age (approx. 1839) have proper foundations / dpm etc? Would the French drain be dug to this level? Sorry, maybe I should read the suggestions above first. Still very worried, but slightly reassured others are dealing with/have sorted out similar situations. Thanks again.

What's in the extension? Is it a kitchen or bathroom by any chance?

Wet carpet sounds like it might be a burst water pipe in concrete flooring...

We have french drains (cost about £2k, but 14 years go). removed all concrete and replaced with lime plaster.

We are end of terrace and a few years ago found that the cottage at the ends drainage was not connected to the mains but was draining under our front room window. It's now fixed and that helped a lot too.

Our timber framed cottage has victorian drains and we are going to reroute them as we have a few unexpected damp internal walls and suspect the drains might be behind it.

I've messaged you with details of a builder who might be of help, depending on the distance he is away from you.

I just typed a long message then deleted by mistake - time to switch off for tonight I think. Thanks to all, may sleep this evening and not lie awake worrying so much!

LBOCS2 - extension is a bedroom. "old" damp stains and small rash-like bumps in much painted over plaster I suspect are on the walls adjoining original cottage. "new" damp marks, wet carpet and black mould is in the opposite corners, i.e. external wall with flagstone path outside and garden sloping down towards the cottage. Does this make sense?

We had similar problems on a Victorian cottage and removed all the patio slabs out the back which had been laid too high. We also discovered that the extension built in the 1980s was only single skin and the concrete floor extended out underneath the patio so when it rained water came straight into the house. We had it all dug out and replaced with gravel. No problems since. For damp in other areas check gutters and drain pipes as well, and any pointing between the stones. Good luck - don't give up!!

Thanks to all for your words of encouragement. I guess all such problems can be remedied if you throw enough money at them (and get the right advice/action of course). We just hadn't budgeted for quite such a big job.

Bilbodog, your problem sounds very similar - could I ask very roughly the costs, i.e. up to £2000 / £5000 or above that?

Poltergoose, love the description of other "venting" - none of the doors here fit tightly and I'm getting used to being able to see through the tiny gaps in planking on door to the loo!

Sorry - I can't give precise figures as we discovered problems at different stages. However, the digging out at the back to lower the ground level and replace with gravel was probably about 2k - it was purely a manual job so if you are younger and fitter than us you could do that yourselves. The floor joists had also rotted at the ends so our builder cut off the ends and treated the wood and built little walls with breeze blocks to hold the ends up and this seems to have done the job - we didn't need to replace the whole floor. Just be wary of introducing too many 'modern solutions' into an old property - breathability is key. Having to have the single skin extension brought up to standard was mixed up with all sorts of other costs. Expect anything you do to an old property to cost more than you think! Hope this helps.