Painted Stone Walls are Damp, help!

[Buzz]

any advice appreciated.

I'm looking to buy a particular house which has been empty and run down for a while. old property with stone walls in the country.

Mostly the walls are painted inside and out without render or plaster. very bad mold smell throughout the house.

A flat roof single storey extension has been built, and what used to be the outside wall is now an internal wall on the ground floor.

No render or plaster has been applied to this wall on the ground floor, only paint on both sides of the stonework.

There are salt growths coming through the paint even at ceiling height on what used to be the external side.

On the internal side is a fireplace which is very wet to the touch and again this has been painted without plaster.

I suspect the source of the damp is the chimney and a non-breathable paint has been used trapping the damp inside the wall.

I would like to know whether this is something that could be easily repaired and what would be involved. Would stripping the paint off and replacing with a breathable paint solve the problem? What is involved in getting the paint off the stone, and how difficult is it? Is there a way to fix this and keep the stone look of the walls, or will it have to be rendered (I know any render should be lime not gypsum).
is this repairable or not?

I'm looking to do as much of the work as i myself, but i have no experience with damp and salt in stone.

 

[Nigel Watts]

It is certainly possible to remove paint from stone. I have been removing paint from my exterior stucco which is a similar process:

These areas are not quite finished as there are still some residual patches of oil based paint (the very pale patches). The colour is also not completely even because of residual traces of possibly original pigment (the ochre-brown areas). The latter don't concern me too much as I will be lime washing over them but the oil based paint residues will need to be removed.

In my case the paint is very thickly encrusted: some lime wash or similar, followed by many layers of linseed oil based paint, then modern gloss, then modern textured masonry paint then modern emulsion. Where there are defects, or where paint has peeled in the past, there is often modern filler which has to be removed.

The whole stripping process can be done with chemicals which will remove everything other then the fillers. The technique I have developed for my house is to strip some of the top layers first using a combination of physical scraping and heat then applying a Klingstrip poultice (Sodium Hydroxide and ground chalk). When the poultice is removed the walls have to be scrubbed vigorously with plenty of water, or hosed down with a pressure spray. Further applications of chemicals may be needed where there are still residues and it is sometimes recommended that one should apply a neutralising solution eg dilute vinegar.

Different paint stripping jobs require different approaches and possibly different chemicals. Strippers of Sudbury supplies some five or six different types of paint stripping chemicals are are very helpful in advising on the best approach.

 

[worms]

Is it possible that the roof is leaking at the point where the extension joins the original house? Or somewhere around the chimney? It might be best to sort the source of the damp as the first move.

Having said that, an empty "run-down" house will smell damp, simply warming it up and airing it might make quite a difference!

 

[robgil]

is the paint bubbling or flaking?

 

[Buzz]

is the paint bubbling or flaking?

i'd say it is "bubbling", there is salt efflorescence behind the bubbles.
the walls are thick stone, welsh cottage style.
If the wrong paint has been used, then the entire outside and inside will have to be stripped i think. it sounds like a very difficult job.

 

[Buzz]

Is it possible that the roof is leaking at the point where the extension joins the original house? Or somewhere around the chimney? It might be best to sort the source of the damp as the first move.

thanks I hadn't given that much thought, it might very well be the roof of the extension. I had thought it might be water coming down the chimney as the fireplace is soaking, or simply rising from the ground.

Having said that, an empty "run-down" house will smell damp, simply warming it up and airing it might make quite a difference!

it is a serious damp smell, not just musty. As it is, i would not want anyone to stay in the place for health reasons.

 

[robgil]

you have found the effect of the damp now you have to find the cause, i doubt its the paint although the paint isnt helping.

 

[Lime]

Is it possible that the roof is leaking at the point where the extension joins the original house? Or somewhere around the chimney? It might be best to sort the source of the damp as the first move.

Having said that, an empty "run-down" house will smell damp, simply warming it up and airing it might make quite a difference!

and

you have found the effect of the damp now you have to find the cause, i doubt its the paint although the paint isnt helping.

I agree with all of that.
The flat roof is the first place I'd look too.
It doesn't take much ingress of water to make any wall wet.
However I'd also expect the chimney to be causing some of the damp too.

Ventilation of the house would be my first priority.
Run-down and long-time empty old houses always smell.
.... if it had been a modern house built with modern materials and left to go into a run-down state as this house it would have collapsed years ago.

 

[Buzz]

thanks for replying all.
My main concern is the salt damage to the stone. is this something that could be sorted out?
I had a brick victorian house with a salt spot in the bathroom about 2 inches in diameter, low down in the wall, the rest of the wall was fine. I chiselled it out back to the brick, replastered and painted a few times, but it always came back.

salt in natural stone is something new to me, and I'm concerned given the extent of it in the wall. assuming the damp source is sorted, what is required to treat and prevent the salt from coming back. the house is in a very wet and humid part of the country.

 

[Buzz]

you have found the effect of the damp now you have to find the cause, i doubt its the paint although the paint isnt helping.

you are correct. I have been in the attic and the top of the stone chimney breast is soaking like a wet sponge. a brick chimney has been built on top of the old stone chimney with slate between the stone and the brick. the slate is wet and crumbling, the bricks are damp, the stone beneath is soaking, the mortar between the stone work is mushy like freshly mixed plaster, you can push your finger through it.
cannot see any fault with the flashing around the chimney (through zoomed camera photos), chimney has a single T-pot and the stack is capped with beveled cement. can't see any obvious fault.

Assuming the problem is a rain leak (given the wetness) rather than penetrating damp, is this a serious problem for the stone chimney breast. Will it be ok when it dries out after the assumed leak is fixed? any thoughts appreciated.

 

[Tom]

Don't worry too much about the smell. That will go once the damp has gone. Our house was cement rendered inside and out on stone rubble-filled walls. When I started to remove the render, water would run down the walls. It had all been trapped in from the render failing on the outside and the water having nowhere to go. It stunk so bad!! A real nasty, dank smell. It didn't take long to dry out once the render was off and the walls could start breathing again. I guess, all told, about 9 months saw the walls dry again. They've remained dry and the smell has gone completely...so don't despair

 

[robgil]

you could try mixing some food colouring or emulsion or something with water then get up there and slowly pour it around the chimney, someone underneath might be able to see where its getting in.
most likely though it will be obvious when you get up there.

 

[AMc]

any advice appreciated.

I'm looking to buy a particular house which has been empty and run down for a while. old property with stone walls in the country.

SNIP

I'm looking to do as much of the work as i myself, but i have no experience with damp and salt in stone.

I see "looking to buy", "I'm looking to do as much of the work" and "any advice appreciated" in there.

If you're planning on loving the house and spending a lot of time, energy and probably money turning it into something beautiful that you love...
Get some professional estimates for renovation from builders with experience in period methods _NOT_ a damp proofing company.
Ask them to anticipate the worst case and use the quotes to get the price dropped to where the repairs make financial sense or at worst where your eyes are wide open to the potential costs.
If you choose to do the work yourself then you'll probably save money and end up with more control over the quality of the work, but I wouldn't start on the assumption that weeks/months/years of your labour are free so you should spend more than the house is worth.

If you were hoping to buy it, do a quick clean and decorate then use it as a home, holiday home or let it out then I would look for somewhere else with fewer problems.

Our current home has cost me more than 4 times my amateur guess at the cost of renovation, taken several years longer than I thought and still isn't finished.
I'm not saying I wouldn't have bought the house and done the renovation, but I was naive and acted with my heart without involving my head or anyone who had more experience than I had (i.e. none). When we eventually got professional pricing, the lowest quote we got was 3 times the money we had originally set aside.
It worries me slightly that even nearly completed, if circumstance forced us to sell tomorrow we would probably come out with less money than we began with despite swallowing 4 years of my time, mortgage payments and representing a part time job for 3 years and a full time one for 1. When I think of the money I could have earned had I not been project managing and labouring on my house it makes the whole thing seem even more misguided.

I do hope the house is worth it and you choose to rescue it from its unloved state. If you're buying with your heart then involve your head and wallet in the decision. Best of luck!

 

[Penners]

an empty "run-down" house will smell damp, simply warming it up and airing it might make quite a difference!

I entirely agree. What I would not do is anything hasty.

A house that has been empty for some time, and in a poor condition, will almost inevitably smell musty and is likely to feel generally damp. It makes sense to check that there are no obvious sources of water ingress - roof leaks, broken or overflowing gutters, blocked downpipes, etc. - but other than that, I wouldn't take any serious steps to deal with the problem until you've had the house opened up, ventilated and warmed for a few months. At that point you can begin to get a true sense of what problems were just neglect, and what are inherent.

But yes, I also agree that a proper structural survey by a chartered surveyor with local knowledge would be well worth undertaking. Be sure to brief the surveyor on any particular problems that you've noticed with the building.

 

[MatthewC]

I feel slightly qualified to comment given the condition of my own recent acquisition. We have had the top of one chimney rebuilt entirely, and both have been/are being rendered afresh, with new leadwork (as well as a refurbished roof).

... the top of the stone chimney breast is soaking like a wet sponge. a brick chimney has been built on top of the old stone chimney with slate between the stone and the brick. the slate is wet and crumbling, the bricks are damp, the stone beneath is soaking...

Slate is "crumbling"? I thought that, being under compression, it was one of the toughest things to use in this situation. Surely the stone can only be "soaking" on the surface? What sort of stone is it? Nevertheless, the chimney does sound pretty bad!

the stack is capped with beveled cement.

That's called the "flaunching", and if cracked it will certainly allow water into the chimney stack

Assuming the problem is a rain leak (given the wetness) rather than penetrating damp, is this a serious problem for the stone chimney breast. Will it be ok when it dries out after the assumed leak is fixed?

It was obvious when I first saw my house that the major issue was dampness. I am really pleased at how much it has dried out in just five weeks, with work being done on the roof (which had several holes in), some natural ventilation, a single wood fire (only lit sometimes) and the removal of some of the shot plaster. It will dry out more when the new guttering is in place and I can get the ground levels lowered.

If you have an obvious problem such the issues you have described with the chimney, I would make plans to get it sorted if it can be done in isolation, and then give the house time to dry so you can see what problems remain. I can't tell you our chimney rebuild cost as the scaffolding was part of the roof work anyway, and the rendering was done on the front one as well, but I'd guess that it would have been around £2,500 - £3,000 if done in isolation

Best of luck

Matthew
http://houseintheenchantedforest.blogspot.com/

 

[Buzz]

... the top of the stone chimney breast is soaking like a wet sponge. a brick chimney has been built on top of the old stone chimney with slate between the stone and the brick. the slate is wet and crumbling, the bricks are damp, the stone beneath is soaking...

Slate is "crumbling"? I thought that, being under compression, it was one of the toughest things to use in this situation. Surely the stone can only be "soaking" on the surface? What sort of stone is it? Nevertheless, the chimney does sound pretty bad!

The slate could be crumbling due to freeze thaw, its crumbling into flakes. The top of the stone chimney below the brick and slate inside the attic is soaking, the mortar between the stone seems to be soaking up the most of the moisture. there is staining on the first floor all the way down the chimney. the fireplance on the ground floor is wet too, so I have to assume that rainwater is soaking into the chimney all the way down, which implies a running water leak from a gap in the roof or flashing. the other side of the all with the chimney has salt deposits bubling through the paint. I'm just hoping its a matter of plugging the gaps and drying out the walls, obviously new lime plaster as well.

the stack is capped with beveled cement.

That's called the "flaunching", and if cracked it will certainly allow water into the chimney stack

it looks good to me, but have not been on the roof.

thanks for posting.

 

[MatthewC]

Our house has two shared chimneys, each with four pots. The problems you describe are absolutely the same as our back chimney, which it would seem was causing trouble next door as well so we are sharing the cost with the new neighbour. We have a bedroom with very wet lime plaster on the chimney breast and holes in the lath ceiling, plus there was damp and mould on the downstairs chimney.

When the work on the roof finishes (this week? I'm excited!) we will have completely refitted slates (to fix several accidental skylights in roof), new lead flashing and rendering on both chimneys, new lead in the box gutter between them and a rebuilt top six courses on the rear one with new pots. (That was where I learned the word "flaunching".)

I can't definitely say which of these issues was causing the particular problem (probably they were all bad), but I'd guess the flashing in the box gutter was the main culprit as we actually did find a split in it. As we're staying here for years, I wanted to properly fix everything up top and then let the house dry out.

Matthew
see pictures on http://houseintheenchantedforest.blogspot.com/