I'm 'damp' in strange places!!

[Lindsey]

I hate my damp course provider with a passion. After 15 years, the memory of their visit has dimmed somewhat. However, the insult that followed that 'injury' is more recent. Having paid an annual guarantee for all those years and finally calling on them to investigate a problem in the morning room, they drilled large holes in all my walls and told me that despite the large wet patches on the wallpaper, the damp course had not failed and I had a condensation problem.! The windows remain remarkably dry however and the wallpaper dries out on dry days and wets again on rainy days. I forgot to mention that the wet patches are above the chair rail and the join between the company's new plaster and my old plaster. The wallpaper has never gone black or mouldy in all the past 15 years. I don't think I would have been surprised if he had said it was tidal!! I only called them because I wanted to redecorate and it seemed the perfect time to deal with the damp. The plaster behind the paper is perfect and salt free. There is even an undamaged layer of estate emulsion underneath. ANY IDEAS ANYONE? There are no leaky down pipes or repointing problems outside and the damp is on interior and exterior walls and about 4ft high and horizontal.

 

[JoceAndChris]

Hello Lindsey, and welcome to the forum.

If your wallpaper has never gone black or mouldy in all those years, it sounds like you're ventilating the house well - excellent. We had just the same thing here in the dining room, wet wallpaper over many years but plenty of natural ventilation in the house! I fixed it by removing exterior cement render.

Reading your post, it sounds like the exterior of the building is either brick or stone. Is it painted? What kind of finish is on there?
And the interior is a mix of cement plaster and lime plaster?

It will sound drastic, but if you can create full porosity ( no plasticcy modern paints, no cement pointing or renders, no gypsum plaster) both outside and inside then your house can breathe again. There ought to be lime pointing and lime plaster if it's a damp weather-taking wall. Wallpaper's fine.

I'm so sorry to read about the damp course and the drilling, most on here believe you may as well sacrifice a goat and hope that might fix your damp.

 

[Feltwell]

Lindsey, there are many and varying causes of damp but a recurring theme throughout most people's experiences who contribute to this site is that damp treatment of the style you describe just does not work and can make matters worse.

You talk about the join between their new plaster and your old plaster. So, would I be correct in saying that their original treatment involved hacking off all the old plaster to a height of about 3', drilling lots of little holes low down and injecting some silicone compound, and then re-plastering with what they probably told you was "waterproof plaster" or similar?

The cement based render they probably applied will simply be masking the damp in your walls. If damp is appearing above that level it's not because the wall is only damp there - the whole of the bottom of the wall is damp, their impermeable plaster is just hiding it. Where the damp appears is the first place that the wall has to "breathe" and let the damp out. What's the outside of the wall like, as Joce asked? Has it been pointed or rendered with a cement based mortar?

You say the damp is on interior walls as well. What's the floor construction in the affected rooms? Has a suspended timber floor been replaced with a solid concrete one?

You've looked for leaky down pipes which is good, are any gutters overflowing? What's the ground level like outside? Is it below the interior floor level?

Breatheability is the key. Most builders, and all damp proofing companies, tend to use products that try to seal out the damp. The problem is that seal is very rarely perfect, damp gets in and then has nowhere to escape. Old properties with solid walls work far better by being able to breathe - so yes, some damp can get in, but it can get out again as well. This is how they were originally constructed, old properties generally only suffer from damp due to either a lack of maintenance or more commonly inappropriate maintenance. The use of modern gypsum based plasters or cement render or mortar does not necessarily cause a damp problem, but it can do. The old lime based materials were slower to work with but are much more permeable to water vapour.

 

[Penners]

the wallpaper dries out on dry days and wets again on rainy days... The plaster behind the paper is perfect and salt free. There is even an undamaged layer of estate emulsion underneath.

Welcome, Lindsey.

Your statement above gives me pause for thought. In fact, to me, the effects you've described don't seem to tie in with a failed DPC. In general, I believe that dampness rising into a wall is a fairly slow-motion effect - the damp percolates up through the masonry and through the plaster. For this reason, I am a little dubious about your seeing such an instant "come and go" in the wallpaper dampness, on wet and dry days. I would also expect to see obvious dampness symptoms in the plaster under the paper and in the paint substrate, too.

Are you absolutely certain that there's no other route by which the wall could be getting damp? For example, was the exterior rendering (assuming you have this!) hacked off up to 1 metre eight, as well as the interior plaster? If so, could there now be cracking in the rendering along the join line of the old and new?

Is the dampness anywhere near a window? If so, are you completely happy that the window is completely sealed into the surrounding rendering? Remember to look underneath the outside sill, which should have a drip bar or groove and be well sealed where the sill meets the rendering.

I carry no brief for damp treatment cowboys whatsoever! But, as I've said, I'm not convinced that your symptoms unequivocally point to the disease that you fear.

 

[Lindsey]

How incredibly kind of you all to take the time to think of an answer to my damp problem. I realize now that I probably gave you the bare minimum,information wise. The house is a three brick thick Georgian construction where you have in effect, a column of brick, a column of windows and so on. The pointing is now all lime mortar after fifteen years of removing cement infills and honeycombed brick work resulting from that. The floor in the room in question is huge flagstones. We have minimal down pipes on this facade because of the listing and try to keep gutters etc clean and the fall on them correct. Last years snow came off like a giant duvet and took a lot of them with it,smashing a table below in the process.! We have a log burner and a radiator in situ. I am coming round to thinking that modern paints, Vinyl based wallpapers etc are not helping. Now the paper is off the walls look superficially dry but feel sticky in the effected areas. There must be some sort of capillary effect happening as suggested that draws moisture up to the break between new plaster and old lime plaster. Also the skim has fallen off the new plaster in places as I removed the wallpaper. We might put in a couple of air bricks. If it hadn't been a condition of the mortgage, we probably wouldn't have bothered with the damp course. And we would be financially better off by the cost of the guarentee (300 quid per annum ) x 15. Isn't hindsight a wonderful thing. Thanks to you all again and hello to yellow belly neighbours in Lincolnshire. Ps. This wing of the house is three stories tall and while the brick gets wet when it rains ,often the ground at bottom of wall is dry. If that makes sense. Also maybe I was a little creative with the instant wet dry thing. It is certainly damp if it's raining but probably takes a few days to dry out if weather stays fair.

 

[Penners]

The floor in the room in question is huge flagstones....There must be some sort of capillary effect happening as suggested that draws moisture up to the break between new plaster and old lime plaster. Also the skim has fallen off the new plaster in places as I removed the wallpaper.

I presume you have skirting boards around the wall in question - do you happen to know whether, underneath the skirting boards, the plaster goes right down and is in contact with the flagstone floor? Or is there a gap between the bottom of the plaster and the flagstones (as there should be)?

Plaster in contact with a damp floor can itself become damp. Do you know whether there's a damp-proof membrane under the flagstones?

 

[Lindsey]

Hello Penners. I know that there is definitely a gap between flags and plaster and I am sure that the flags sit on ground,earth or sand. When we first moved in, we used to get a fluffy deposit on the floor which stopped when we refurbished and heated the room. It used to be the farm office and not a place to linger in. This process is a bit like a Sherlock Holmes mystery. Does that make me Dr Watson?

 

[Penners]

Hmmm... next question: is the damp patch in one particular area, or is it right along the treated wall(s)?

Incidentally, I'm staggered that this company, having carried out the "damp prevention work" ( :roll: ), has charged you £300 a year for the warranty! The one and only time that I had such work done on a house (before I learned the truth about such treatments) the company gave a 30-year guarantee as part of the deal.

 

[Lindsey]

On three walls,horizontally, one of which is a wall between the room and a lobby,two are external and the fourth is the chimney breast wall and damp free.........b They call it a guarantee, not to be confused with a warranty and not to mention any names, but think of two words that could replace' pay to borrow 'and 'extinguish life or murder' and your on the right track companywise!!! I feel that I've fallen into a gold mine of knowledge and information with you guys. Thanks again to you all. But please don't anyone loose any sleep over this problem. I'm not up to my neck in water or anything worse. In fact, I'm going to light the fire now and have a glass of something that cheers! Lindsey.

 

[Penners]

And were all three of those walls treated?

Thanks for the tipoff. I'll keep my eyes pen for a company called "Interest Slaughter"! :?

 

[Lindsey]

All three treated with break in plaster at chair rail height. And try rento slaughter!

 

[Penners]

Well, to be honest I don't know how much more help this forum can be to you. Based on your additional information I have to agree that - if all three treated walls are showing clear evidence of damp at the point where the treatment company's plaster meets the old plaster - then it does sound very much like a failure on their part to cure the problem.

But if they've categorically denied responsibility, it seems to me that there are very few courses of action open to you:

1. Are they a member of http://www.property-care.org/? If so, then you may perhaps be able to take the case to that organisation. Given that thingykil are well-known and countrywide, they may well be members.

2. You could employ an independent structural surveyor to come and give his opinion on the matter. But of course this is going to cost you money. And even if he finds in your favour, you'd still have to persuade the company to respond positively to his findings. Pursuing legal redress would of course be open to you, but that entails further expense without an absolute guarantee of success (although if you were successful in court, you could probably add the surveyor's fee to your reclaimable costs).

I'm afraid there's no easy answer.

 

[Penners]

PS: I've just had a look at that company's website, and it seems they are members of the PCA.

http://www.rentokil.co.uk/residential-customers/property-care/damp/rising-damp/index.html

 

[Lindsey]

We have come to the same conclusion that it will cost us money to pin the company down qnd it could be a purely acedemic exercise. I certainly wouldnt want them back again.As we intend to leave this place in a wooden box and have plenty of other avenues to spend any surplus cash, it comes down to whether we can live with the problem. I've been out today and bought non vinyl paints. If visually this does the trick, I shan't worry about future surveyors and their damp meters. It has been a puzzle for so long though and I now feel that I have more insight into the problem. Thank you. Lindsey.

 

[Moo]

I am sure that the flags sit on ground,earth or sand.

Just as they should be.

And you're definitely doing the right thing by replacing the plastic paint.
Many years ago (before we discovered the blessed PPUK) we made the mistake of using paint that was ever so authentic as far as the colours were concerned, but was also modern emulsion. Over the years it has flaked off in nasty patches (taking a fair bit of plaster with it) and the whole place is now in desperate need of fairly drastic treatment (we've decided to go for Earthborn paints because they are, apparently, hard wearing and will tolerate being used over a patchwork of different surfaces)

ps
While you're at it, have you considered getting rid of the nasty waterproof plaster and having it re-done with lime?

 

[middi]

If ( from what you describe) damp possibly permeating through the walls, as opposed to " rising damp", ie- from the ground up, I would be tempted to prove the point by attaching breatheable roofing membrane ( approx £ 150 for 50 sq metres) to one or possibly two of the affected elevation for a couple of weeks (or longer) and monitor the difference with an eagle eye.
Damp is a funny " beast", when it " bites" the pain has a delayed effect. To stop the " beast" biting again search and eliminate it at the entry point.
If it proves too costly and /or difficult to eliminate it at the entry point the other obvious remedy is to make sure it escapes at a faster speed than it takes to gain entry. ( combination of heat and ventilation ? ).

Sorry about the limerick , I hope it makes some sense.

Middi

 

[JoceAndChris]

I like Moo's advice above (and everyone else's of course).

Lindsey, it sounds like you have a very good and sensible approach. Most old buildings are going to be a mixture of old and new materials- lime plaster skimmed with gypsum, vinyl paint over distemper,etc. My feeling is it's bordering on the crazy side to pick the whole building apart on the inside and do it in lime (though there've been a few quarrels on here on that topic so perhaps it's best left alone). If there is a problem though, and you can't live with that problem, then stripping out the modern stuff and using lime is the answer.

 

[worms]

For what its worth, we fell into a similar trap and, due to mortgage conditions, got the same company as you out to inject a gable wall (rubble construction) and replace a section of failing lining inside. In our case the wall was already lined with batten and gyproc and this was replaced with tanalised batten and more modern gyproc, so no junction to proper plaster, just a very poor join and a line of tape. But there was no question of on-going payments and I guess we were lucky to get away with them only doing the gable wall, since the man with the meter determined that the gable was the only damp wall (missing the wall that was damp enough to rot the joist ends!).

My assumption is that on our gable, the real issue is condensation behind the dry-lining, where a warm humid kitchen meets a cold weather-facing external gable wall (with cement infill and many layers of plastic paints). Air vents designed to air this only succeed in making our cupboards damp, since there is no proper air circulation. The damp-proofing works have probably given us 25 years before the tanalised timber fails, so this is not high on our current list of jobs to sort out.

I wonder if your issue is similar, but with the old plaster getting damp at the junction, caused by condensation on the bricks behind the lath and plaster?

 

[Flyfisher]

My feeling is it's bordering on the crazy side to pick the whole building apart on the inside and do it in lime (though there've been a few quarrels on here on that topic so perhaps it's best left alone). If there is a problem though, and you can't live with that problem, then stripping out the modern stuff and using lime is the answer.

I entirely agree and also favour the pragmatic approach (while also acknowledging the purist's misgivings). With an unlimited budget I'd be writing this from a Carribean beach while a team of expert heritage specialists strip away every last inch of inappropriate modern materials and replace them with more suitable traditional materials.

Meanwhile, back in the real world, modern materials won't be causing problems everywhere so it seems reasonable to first tackle the problems that are all too evident and then move on to the less urgent problems that might be storing up problems for the future. Also, as Joce rightly implies, it's quite possible to live with some 'problems', depending on personal attitudes and preferences.

I liken this to weeds; unwanted plants can either be mercilessly targetted for destruction or removal and consume vast amounts of time and effort in the process or they can simply be redefined as wanted, or at least don't-really-mind, which solves the 'problem' at a stroke and suddenly frees up all that time and effort for other things. :wink:

 

[Penners]

We have come to the same conclusion that it will cost us money to pin the company down qnd it could be a purely acedemic exercise.

Does that mean that you're going to give up? I do hope not! I can only say that, if I were in your shoes, I would be making such a continuous bl@@dy nuisance of myself to them that they would - eventually - do something about the problem (one hopes). It might require a great deal of tenacity and a snowstorm of letters to people at ever-higher levels in the company, but with the right threats about trade associations, the press, TV programmes and so on, you could get them on the run.

Other than that, I must add my vote to the comments made by Joce and Flyfisher. Target your work on the house where it's most needed.