Old Cottage, problem after wall was reskimmed

HI
I wonder if anyone can give me some advice.

We live in an old sandstone cottage. We had some walls reskimmed in March last year, all of the walls have been fine with the exception of the a wall in the spare room, which is on an exterior wall (as were all the other walls that were done) It is east facing and a gable end wall. It dried out, left it for 10 weeks before repainting. All seemed fine and then about three months later large damp patches started appearing all over the wall.
Our first thought was that we had water getting in somewhere, so we inspected all of the ourside wall, but no damage in any of the pointing , obviously no gutter as it's a gable wall. In short can't find any evidence of water getting in anywhere.
We asked the plasterer if he could have a look for us, he wondered if some damp had got trapped in there when it was redone, suggested perhaps it would be better done in sand/cement skim. He suggested that we first get a damp expert around ,which we did yesterday, he said it was impossible for damp to have got trapped and his only suggestion was to build a false wall with insulation behind at a cost of aoorix £800.
His meter was flashing red all over the wall.
The wall is beautifully shaped around the window with deep curves and a false wall would ruin that effect I think.
We are putting the house on the market, the estate agent has been around and taken all photos and is just waiting for a phone call telling him the damp problem is sorted and giving him the goahead to market it, so I am desperate to get this sorted out . Obviously can do without spending £800 on it right now.
My husband wants to paint the whole wall in dampseal and then an oilbased primer and then paint it. I have done the odd patch in it, but damp appears elsewhere.
What do all you experts out there think?

I would not expect it to be anything to do with the plastering if it didn't appear until 3 months later .There must be somewhere it is getting in ,it doesn't need much for water to get in and once it's found it's path will just get worse .
Have you tried a dehumidifier in there to dry it out then look and see where it comes back first if at all ?

Thank you for your reply. Yes, we bought an Ebac dehumidifier and it's been on non stop for 4 weeks, it did seem to dry out really well, so I thought it safe to repaint it. I put some dampseal paint over the stains and then emulsioned it, but strangely the damp patches appeared again overnight, some in completely different places. I
It's driving me mad, desperate to get the house on the market.
We've lived in the cottage for 18 years, no problem ever with damp.

Just thought, maybe I should add that the damp patches did not appear until after we started using the room as a nursery for my newborn granddaughter, obviously not using it now for her. Before this , nobody ever slept in it. It has always been the coldest room in the house though.

1. FWIW: perhaps you should move the child from a damp room, it would also give you a chance to observe and look for condensation signs?

2. Dont seal or oil paint anything.

3. FWIW: all this will have to be revealed at discovery time during any house sale.

4. You have some suggestions from others above, and if you do a little research on diynot.com forums etc. you will soon be more knowledgeable in what to look for and Q's to ask.

I did actually say in my previous comment that the baby is obviously not sleeping in there now...

My apologies, i missed that further detail.

I'm going to buck the trend here and say that this does have something to do with the skimming of the walls. Looking back at you timescales you say skimmed in March, left for 10 weeks to paint, then 3 months later damp patches. So that puts it around autumn time? Getting colder outside and warm inside with heating perhaps?
What type of plaster was used and has this plus the paint stopped the natural ability of the wall to breathe? What is the age of the property and how thick are the walls?

It sounds like definetly a damp issue even tho you say its not coming in from outside . How high are the damp patches from the ground? If they are 1200mm or below then it is probably rising damp (that is if the room is on ground floor level), If it is an upstairs wall then it will be penertrating damp, water will be getting in from somewhere, Also the "damp-proof expert can't be much good if he is telling you to hide it behind a stud wall. Like kbdiy said what was the wall plastered with? If it is light weight plaster (not sand and cement and lime) then if there's damp in the wall then the plaster would not hold it back, I am not saying that sand and cement and lime will, if you have a issue with penertrating damp, but it would let the wall breathe a little. You have to find out what is causing the problem ,get a few "reputable" tradesmen to inspect the gable and pick their brains, Have you thought of hacking all the plaster off and if the stone wall is fairly good have the joints racked out and all repointed it could become a nice feature. You could hack the wall off rack out the joints and put a dehumidifier in there for a while and see what water is pulled out. But you have still got to find where it is coming in ..Hope this helps.If you get a reputable firm in then they would gaurantee their work (like has been said before ,the chemical company that supply the chemicals for the contractor actual gaurantee it) but you would be issued with a 30 year gaurantee (some times you may have to pay a little towards it) but you could go ahead and sell the house and pass the gaurantee on to the estate agents...

Sounds like condensation damp to me. The water vapour condenses on the wall, soaks in, which in turn makes the wall colder and more prone to condensation, which then soaks in and gets colder. etc. etc..

That is why insulated stud would help.

joe-90 said:

Sounds like condensation damp to me. The water vapour condenses on the wall, soaks in, which in turn makes the wall colder and more prone to condensation, which then soaks in and gets colder. etc. etc..

That is why insulated stud would help.

Click to expand...

You cant just hide a nice "feature" wall by putting a stud wall in front of it joe....Better to cure the problem...

The room is an upstairs bedroom. Three external walls, one wall was reskimmed and that is obviously the one we are having the problem on.
It was plastered with Carlite something?

Cottage is approx 180 years old, sandstone solid walls, no cavity , walls approx 8inches thick , but thats a bit of a guess.

Started using the room in about Mid June time, no damp before we started using it and then within a week or so these damp areas started forming. Noticed then first all around the window, which is not double glazed. Then started appearing in random places on the wall. No mould anywhere. Anywhere that's been drilled it also comes through, ie screws for curtain rail and tiebacks.

The external wall has been inspected by two local reputable builders who I have used often and have a good reputation. We did reseal around the window frame just in case, but thats made no difference.

The room has been kept a bit warmer as obviously to begin with the baby was in there, always been a freezing cold room.

I'm at a complete loss with what to do next. I don't really want to put up a false wall. It's a really tiny bedroom and that will make it just smaller and as I said previously spoil the character. I note your comment about leaving the stonework exposed but it's such a small room and a bit dark too, that I don't think it would look good.

My gut feeling is that its something to do with the plastering that was done. I really don't think that there is water getting in anywhere.

I much appreciate all your advice.

churchcottage2 said:

The room is an upstairs bedroom. Three external walls, one wall was reskimmed and that is obviously the one we are having the problem on.
It was plastered with Carlite something?

Click to expand...

carlite bonding is an old name for thistle bonding which is an undercoat plaster, now you say you have had this wall reskimmed but bonding plaster is an undercoat, was the wall back to brick? was it float and set with bonding then skim? is it a solid wall? bonding isent a wise choice to use on an external wall if its solid

I'm sorry I should have perhaps said that it was a modern plaster, the damp guy who came around mentioned the name Carlite plaster so I just remembered the name!

is a solid wall.

joe-90 said:

If it is a condensation problem as I suspect, then to seal it and sell it like your husband suggests is probably the way forward. It's a bodge - nothing else, but then it won't be your problem as you'll be long gone.

Click to expand...

Too late for that I think - they have already tried to seal it (see OP) and the damp still appears. This is a classic case of the wrong treatment being applied to an old property and condensation is the result. The only solution now is to strip back and have it plastered by someone who actually knows how to deal with this type of property.

It may cost but at least you'll be able to sell with a clear conscience and sleep nights! A lesson learned for anyone who owns an older property.