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Damp issues in stone built house
Hi, I was hoping for some advice. We recently bought an 1901 stone built house. The survey uncovered significant penetration damp issues and consequently structural issues. We proceeded with the sale and have hired damp specialists. The house was originally pointed in lime but the previous owners repointed it in cement and then applied Thompson’s waterproof seal spray to the outside which has significantly contributed to the issues. Our specialists have said we should strip back the walls to the stone and put permaseal membrane on top. Then on the outside when the Thompson’s seal wears off, put stormdry cream on. All joists will be repaired and wrapped in a waterproof membrane. The damp is on every external wall in the house. Images attached. Is this the right advice?? It’s so much money to get it wrong.
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10 Replies
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I’m afraid they’re not specialists if their advice is more magic creams! Don’t go any further with the snake oil salesmen – just need to identify where the damp is coming from then work on letting it breathe. Where’s the problem?
Start with the obvious – remove cement, check external ground levels and pointing, check for water ingress / drainpipe leaks / hard surfaces up to the wall etc etc.
Picture pictures pictures!
sounds like you already know this, but sealants are not a solution, they’re most likely the problem. Adding membranes and magic creams isn’t going to help.
So, first up, you need to get away from the ‘specialists’!
Next is find the problem, rather than spend a fortune hiding it. Pictures of the outside walls will be helpful here? Lots of good advice and knowledge here!
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This is awful. They tell you the waterseal ‘failed’ then they intend to charge you to do exactly the same thing by way of a treatment!? Absolutely not!
Can we go back to basics and try and work out what is causing this damp? (Compounded by the waterseal of course ☹️)
Can you please add some external images?
And before you do anything else, read this until you understand the principles of keeping an old structure dry. Then we can work out some sort of p,an to resolve it.
Unbelievable, I’m really shocked, though I shouldn’t be….
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What a beautiful house. As everyone else says you need to identify where water coming in . It’s doesn’t take much to constantly trickle and cause problems . Problem appears to be walls can’t dry out. Is that cement below window? I don’t see any handles either. Is it a sealed window? That won’t help. airflow really important . As said below read about breathability etc and don’t seal anything . Don’t panic. You can check to see if leaky chimney( check all pointing and top chimney), blocked or cracked gutters, blocked vents etc and I’ll bet you identify a few causes you can sort out relatively quickly. I’m about to remove soil a neighbour piled against my wall I’m hoping that will help out as walls unsealed stone.
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First thing you need to do is enquire about cleaning the Thompson water seal from the external as that could be causing most of the problems, find a competent operative who has a Thermatech or Doff hot steam pressure washer, they should be able to advise you accordingly & remove the film coating which is blocking the porous stone & brick facade…could do with some closer images of the mortar pointing too as it could have been pointed in the wrong mortar. There’s a few other issues that could also be causing the problems too, so you’ll just have to do a check list starting from the chimneys, roof, lead flashings, flaunching, coping stones, gutters, bays, downpipes, mortar pointing, air vents & ventilation, ground levels & drainage for any external remedial work, internal check vents, sub floors, pipe leaks, good ventilation from the subfloor to the roof space & the correct type of plaster & any fireplaces blocked need opening up or venting properly for a good air circulation to avoid condensation & moisture building up.
That gable wall stone work looks saturated on most of the surface area, that’s probably due to it being coated in Thompson water seal, also looks suspiciously like it could be pointed in cement, the internal plaster work looks like it’s gypsum, so at an educated guess the walls are basically holding water and not vapour permeable, that’s the first course of remedial action if this is the case so the external/internal walls can dry out & be restored back to the original material it was built with.
Also looks like two of those walls in the image are close to the chimney breast/stacks so again I suspect you’d probably need to check the top of the flaunching on the stacks, cracked pots & make sure they have sufficient weather cowls or aren’t capped & also the pointing & lead flashings aren’t missing or failed, you’ll probably need some drone footage of the roof, could even be blocked or failed lead back gutters that need maintenance or replacement.
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Driving rain is one of the main problem judging by how wet the external walls are. The solutions are to bag rub the stones or limewash to seal any micro fractures but you might not allowed to do so if in conservation area and/or national park. Of course after rectifying any inappropriate materials used.
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some good advice here. As well as the guide Jane Schofield linked you too, have a look at this one too: https://www.spab.org.uk/advice/technical-advice-notes (scroll to the one called ‘Control of Dampness’)
It’s critical to establish the cause of the water ingress and there may be one thing or a combination so it’s likely to be a process of elimination. Once you have established that and addressed it, then it’s a case of stripping all the poor materials away and replacing them with the right ones to reinstate its breathability and to allow the trapped damp to evaporate. This is never achieved with membranes, creams, or waterproof coatings. If you can’t work out where the water is coming in, instead of a damp specialist get a decent surveyor who understands old buildings – we may be able to suggest people depending on where you are.
spab.org.uk
Technical Advice Notes | The SPAB
Our free-to-download publications include an expanding suite of Technical Advice Notes aimed at providing authoritative and practical references for those involved with caring for and repairing old buildings.
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Nooo we bought a 16th century stone farmhouse previous owner spent a fortune ‘tanking’ the walls. All that did was stop the walls breathing. It’s a year since we removed it from the kitchen walls which wwet to the touch once the modern plater
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We are currently rectifying issues with a house that was saturated (although not brought up in the survey…). We’ve taken all the external walls inside back to brick and are hoping to get the cement render off the outside. In the two worst rooms the previous owner must’ve had similar advice after pointing out damp and I presume it being cold. They were also tanked and the upstairs room covered in polystyrene. Both trapped moisture and that ended up in floors and joists we are still in the drying out phase but I would consider seeking heritage advice as DPC and things like that aren’t usually appropriate and only mask the symptoms all over again.
For us we are replacing the windows for timber and lime inside and out. We’ve added wood fibre boards for insulation in the vaulted ceiling in one room too and plan to use an insulated Cornerstone plaster on walls that are external facing. We get battered by the weather on the gable end so hoping this all helps moisture move through better
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So making only the outside permeable on a single skin wall would go quite a way to sorting damp problems as there would be at least one direction the water could go?
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180 degrees away from what is the correct advice. They are absolutely anything but experts.
Just think – the existing waterproofing plasters and paints haven’t worked. Why do they think more of the same will? Other than they get to charge you a lot of money for a failed approach, again.
The building needs to work with moisture and allow its movement, not trap it in.
See the link on Jane’s post above/below – and proceed from there.
This is the best internet forum anywhere – stuffed full of real experts freely giving their advice. Ask away, once you’ve done some reading and you’ll get real value from the answers.
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