Rising Damp in Stone Village House

[MrFixit]

Hi, My first post so I hope it's not too long and I am in the right place.

We have a very small 1 up 1 down stone house in a terrace at the top of a hill. There has always been a slight show of salts on the pantry wall which is under the concrete stairs, but no damp smell. Previous owners cladded the main room with T&G up to about 1.5mt presumably to cover up the salt show there.

We have been letting the house for ten years with no problems until recently when the Agent said that they can no longer let it as it is damp.

When we checked there is now a lot of moisture showing up to 2mt wet to the touch on the stone party wall and also on the central wall dividing the main room from the tiny kitchen., which is about 400mm thick so presumably stone also. The walls are plastered but now so soft it can be dug out with a screwdriver, (which the technician did to take his sample) so this is presumably responsible for wicking and will obviously have to all come off.

Because we are on a hill the neighbours house floor is about 600mm higher than ours. It is an ancient village so the houses are probably over 100 years old. The neighbor has admitted to me that a false wall was built on his side many years ago so we can't tell if he has the problem also.

I had a "Free" damp survey by a specialist firm who detected nitrates which they said was definately rising damp not fresh water or a broken drain and are suggesting injection and tanking but only on those two walls and a cost of nearly €11k which is 25% of the value of the house at the moment. My concern is that if they only do half the house then it may well develop on the other walls and of course that would be outside their guarantee so another €11k please sir.

I have read a previous post by Chancer in 2012 where I think it was Thiéière said that the injection creams like "DryZone" were very good and their video showing the system looks well within my DIY capabilities.

As it is a while ago I thought it best to start another thread so as to get up to date info. Has anybody used these creams to good effect. Once the cream is injected is it necessary to render with a waterproof render? if so what is the best. (my plastering skills are not good). Would a coat of a white bitumen waterproofer be adequate rather than rendering.

Is the cream and injector gun available in France or is it cheaper to order from the UK? (my French is not good).

Thanks for any suggestions or experience anybody can pass on.

MrFixit.

(entering new DIY territory)

[Théière]

Hi,  First of all welcome, what stone is your cottage made from?  Limestone possibly.  Rising damp doesn't usually climb higher than 1 metre as the weight usually holds it back at that level.

The issue with putting in a damp proofing is the stone won't then wick the moisture away but instead will saturate the lower stone which if it is lime will degrade.  Your neighbour has probably compounded the issue by sealing their side up so the only way out is yours  €11k is p1ss take.

With you at the top of a hill I am somewhat surprised but what soil have you, clay/lime it could over the rainy winter have saturated but drainage and ventilation are the best ways forward. Easy of course when sitting at the computer without real data of humidity, moisture levels etc

[ventodue]

Hi and welcome,

I’m afraid that I can’t answer your queries

about injection creams, having no personal experience of them.  However, I would advise you to be very

suspicious of the diagnosis you’ve been given. 

Here’s why:

1. 

You say you’ve been renting out the house for 10 years, but only now has

this ‘rising damp’ become a problem.  Well,

rising damp doesn’t work like that - it doesn’t just ‘appear’ after 10 years.  Rising damp comes from water that is under the

wall; and this water will start to rise through a stone wall, with its fine

capillary pores, as soon as the wall is in place.  So, for rising damp to appear after all this time

would require a new source of water to have found it’s way under your wall

somehow.  Do you have any reason to

suspect this ?

2. 

You say the walls are wet 2 meters up. 

Again, this sets the alarm bells ringing.  The size of the capillary pores which lead to

rising damp means that it rarely gets above 1.5m; and you finding the walls wet

to the touch at such heights makes the alarm bells ring even harder!.

3. 

You say the house is on a hill.  So,

obvious question: where do you think this the water could be coming from,

especially during the summer?  Do you

have reason to think that there may be a spring or other underground water

source under your house?  For example, is

there a well in the cellar?  If not, you have another reason to be suspicious

of a diagnosis of rising damp.

4. You say you had “A "Free" damp

survey by a specialist firm who detected nitrates”.  This is presumably the very same firm who is

now trying to sell you an expensive rising damp solution?  Just remember, free advice is worth exactly

what you paid for it!  I need say no more

(I totally fail to see the relevance of the claim that they found nitrates in

the sample, btw).

What I suspect what you have is a bad

condensation problem.  Here’s why:

You say the damp is on 2 walls, one a stone

party wall, the other a wall between the kitchen and the main room.

1.  I

bet that stone party wall is cold? (particularly if it’s the one your neighbour

has built a false wall against).  Any warm,

moisture-rich air will readily condense on that wall, saturating it from top to

toe.

And the wall between the kitchen and the

main room?  Well, what do your tenants do

in the kitchen?  Boil kettles and pots

and pans of this and that and - hey presto! 

Condensation on the dividing wall.

And why now?  Almost definitely related to a run of tenants

who’ve done a little more boiling of kettles, taking of shower etc than others

have done in the past!

Solution: install some fresh air inlets and

some stale air outlets.  They don’t need

to be fan driven, altho’ this would be best; but be sure to put the inlets down

low and the outlets up high (warm air is lighter than cold air).

P.s. Please be aware that injection of thick

stone walls, normally using silicone, is more of an ‘Answer to a Maiden’s Prayer’

than a practical solution.  Put simply,

the silicone rarely manages to fill all the pores that lead to rising damp -

and the problem persists.

HTH

Craig

[andyh4]

I have to agree with what much of what Ventodue has written. Rising damp does not suddenly appear.

I note you have called in an expert company who have detected nitrates.

[ Please note my definition of expert - from two ancient roots -

Ex = something that has been

spert = a drip under pressure]

They have decided that it cannot come from a broken drain - absolute b@11@cks. The best source of fresh nitrate from a natural source for the garden is manure - AKA pooh and pee. I know this from my gardening antics where I add manure to improve nitrates.

My best guess is that someone uphill of you has a broken drain/sewer. Most likely two or three houses up the hill or more and not your immediate neighbour, in order to give the hydrostatic head to produce damp at 2m above floor level. Talk to some other neighbours above you and see if they have seen anything.

[MrFixit]

Thanks Thiéière, Ventodue & andyh4 for your very full and quick replies. Sorry not to come back before but am helping a friend out with decorating and we only have wifi at the bar.

I don't know what rock it is, but when I cut the wall out for the coffre d'eau it was very hard and didn't appear porous at all, the ground is probably clay as most around here is.

Not being at the property I think I misled on the dimensions a bit. The cladding is probably 1,2mt and the damp about 30cm above that so probably exactly 1.5mt.

I don't think it can be condensation as the tenant left about six months ago and the water is turned off so no source of condensation.

I think the broken drain is a distinct possibility and naively hoped the "experts" would be able to confirm it but of course he was a salesman out to make as much money as possible regardless of the facts. So how do I get a fairly anti English Mairie to dig up the road to find out if their drains are defective. Which is why I had resigned myself to having to treat it as rising damp and trying to stop it coming in. Hence the question about the injection of the cream.

Another suggestion by some people is to take the plaster off to stop the wicking and cover with polystyrene backed placo. then sell the house. Which I am not sure about with the modern requirement for disclosure of defects but it may be a solution as it seems to have worked for the neighbor on his side.

Any further thoughts?

MrFixit

[Théière]

[quote user="MrFixit"]

Another suggestion by some people is to take the plaster off to stop the wicking and cover with polystyrene backed placo. then sell the house. Which I am not sure about with the modern requirement for disclosure of defects but it may be a solution as it seems to have worked for the neighbor on his side.

Any further thoughts?

MrFixit[/quote]

That of course is your decision and although putting a plaster (metaphorically speaking) over the issue will only be a temporary bodge the mould will grow and it will smell.  More info on the stone the wall is made of.

[Doodle]

Hi,

Two years ago my next door neighbour (holiday home) forgot to fill the oil tank before closing up for winter. Normally the heating is set to 10 degrees over the winter period. When I went in to check all was ok, not only did the place feel cold and smelt damp but I found the stone walls in one room which originally was a garage were wet on one side and covered in salt crystals on the other. We got the oil tank filled for them and after a few weeks the walls had dried out. No problem before or since.

Incidentally we had the same problem with a stone wall room which at the time was not in use just used for storing tools etc, we got a builder in to have a look and he said it needed some heating and ventilation. We bought a plug in thermostat heater set it to 2 and it did the trick. Could a lack of heat be your problem?

[Chancer]

Agreed, lack of use, heating and ventilation will make all old houses without the benefit of cavity walls, damp pproof course and damp proof membrane run with damp.

Whatever you do, do not use polystyrene backed doublage what is now my living accomodation was once a commercial kitchen, it had and still does have damp walls because a car park has been built behind 1m higher than my floor level, it had polystyrene backed doublage and the whole room was black with damp and fungus, uninhabitable and a health hazard yet it was being used as the kitchen for the hôtel [:-))]

When I scraped off the gellified mass that was once plasterboard the polystyrene behind had decomposed into millions of little billes.

I have done no damp-proofing to this annexe although I did a proper chemical injected DPC on the main building, I used metal rails and moisture resistant plasterboard, the flat is occupied, heated and most importantly well ventilated with a VMC and 8 years on I still have no damp problems.

[Quillan]

We have an end of terrace farmers cottage down in Kent. My family have owned it since the mid 60's and we have never had a problem with regards to dampness until we had one particular tenant. A mother with two children who had just left the family home, separated from her husband. I was contacted by the agent who told me there was loads of damp and mould in the property so I went to investigate and a right mess it was to. Long and the short of it was I employed a specialist surveyor to look and issue a report.

His recommendations were that ventilation of some sort should be installed as the tenant had loads of furniture most up against walls and never opened the windows etc. He was very good and told me exactly what to do to put things right including installing central heating with frost stat for when nobody was there and the house was closed up. He cost me around £400 but saved me a few thousand in fines and having to pay back the rental money plus finding alternative accommodation. Turns out what the lady wanted was a council house for her and her kids and needed to be evicted to get to the top of the list.

Anyway what I wanted to say by using this as an example is to get professional, qualified and independent advice. I have no clue what you would call one of these people in France but they must exist.

The road by the way if it has a 'D' number belongs to the DDE and not the mayor and if a survey is done and there is a problem outside the DDE should be contacted and as far as the mayor is concerned tough luck, it's nothing to do with him/her.

[ventodue]

Lots of good info in the posts above.  A few comments:

1.  Before dismissing condensation as a possible cause, please consider knee gel's point (reinforced by Quillan's post) about condensation ocurring in unoccupied buildings.  It's not unusual, being all to do with relative humidity levels and the dew point.

2.  If you tell me where you are in the Languedoc, I may be able to tell you what the rock is. The area is mainly limestone, of course; but there also some areas of volcanic intrusions, while the Espinouse/Montagne Noire is metamorphic - mainly schists, but also some granite.

3.  If you suspect a broken drain, there's no need to dig the road up to find it!  Breaks in drains are found using an endoscope camera - these kind of things:

http://www.fiberscope.net/pipe-pipeline-sewer-drain-duct-snake-camera-inspection-push-cameras.html?gclid=CPi207XnlsQCFdMatAodp2QALQ

Do you know who might be responsible for any drains that might run under, or within the potential 'catchment area' of, your building?

4.  Please do not pay too much attention to whoever is advising you to, "to take the plaster off to stop the wicking and cover with polystyrene backed placo. then sell the house."

a) I don't understand what he/she/you mean by 'plaster 'wicking' the water'. If you have rising damp, it's not the plaster that is the problem - nor is it a problem if the damp is due to condensation!  Taking the plaster off will achieve nothing apart from leaving you with an unfinished wall - and a damp problem! 

b) As Chancer has warned, sticking insulated plasterboard on a wall suffering from rising damp (or any other form of water penetration) will just make the problem worse - much, much worse.  Insulated plasterboard is, however, a suitable response to cold bridging, a phenomenen which, btw, encourages condensation.

c) Selling the house in the knowledge that there is a damp problem which you have now been advised, wrongly or not, is due to rising damp - and which your letting agent is also aware of - but not disclosing it will open you up to legal action under the principle of 'vices cachés' (hidden defects).

[ventodue]

[quote user="Quillan"] <snip> ... get professional, qualified and independent advice. I have no clue what you would call one of these people in France but they must exist.[/quote]

Indeed they do, Quillan [:)].  Tap 'Expert+diagnostic+fuites' into your preferred search engine to get a bucketload (ha, ha!) of propositions.  Like this lot, for example, who appear to operate in MrFixit's patch  ...

http://www.ax-eau.com/

[MrFixit]

Hi thanks for all the suggestions, I wrote a reply this morning but lost the internet just as I submitted it and so lost the lot. Teach me to compose in Notebook first when I have a dogy connection.

I have PM'd ventodue with our village so perhaps he will suggest the type of stone we have so perhaps Théière will be able to say whether the waterproofing creans will work.

I take the point about condensation but the house has been unoccupied for long periods during the winter before without the problem.

So everything points me to think of the broken drain, I am sure the road does not have a number, it is just a tiny village street so I think it is the Mairie's domain. Perhaps I should ask the local Notaire who is actually in the same street to help me with the Mairie.

As far as asking professionals I did that, but of course they are in the business of making money so it is in their interest to be "economical with the truth" I am not sure I would get much more unless I could find a completely independant damp expert, but his fees would probably be quite high as we are miles from anywhere important enough to have an independant "expert."

Yes the false wall suggestion does seem a bodge and perhaps the French might get away with it but I would always be thinking it will be coming back to bite me in the bu++.

So perhaps if I install a VMC the only other answer it seems if we can't go forward with the drains is tanking which I am sure I can do very much cheaper than 11k even if I have to pay somebody to do the waterproof rendering which I probably do not have the knack for.

So it is back to asking for people's experience with the injection creams I think Théière and Chancer mentioned in a previous post that they had used them. But with Random stone walls rather than brick.

Thanks again for all the suggestions so far.

MrFixit

[Chancer]

My walls are solid brick, I used the old fashioned white spirit and paraffin wax type damp proofing fluid injected at high pressure. Even in relatively good brickwork most of the product just whistled out of crevices, you can tell from the pressure drop that its going somewhere, by the time you find it, it may be the other side of the wall or have dropped down into the basement or floor slab you can easily have lost half a drum of expensive fluids. A stone wall with all its voids is an absolute no-no in my mind

All the so called pros are going to do for their 11K is drill a few holes, give a quick squirt of fluid in each one and then sign the worthless guarantee paperwork which is all that you are really buying, a couple of hours tops on site and then you read that to keep up the guarantee they have to come back regularly to empty your wallet.

To do the job properly the lances need to be completely sealed in the hole, its better to drill them so they end in the middle of a brick, then the pressure needs to be maintained until the product eventually weeps from all the surrounding bricks on both sided before moving onto the next array of holes, if it works properly it can take 20 minutes a go and use surprisingly little fluid, what they will do with a stone wall is to give each leaky hole a couple of seconds, fluid will go everywhere except where its needed.

I did some tests beforehand and the results were really enlightening, I put some dry bricks ina  water bath for a couple of hours and weighed them before and after, they soaked up water like a sponge, an amazing volume, then I pressure treated a brick which took a moderate volume of fluid, allowed it to dry for a couple of days and then did the water bath test, no water take up whatsoever, proof that it does work in ideal conditions.

Where the fluid flooded my workshop floor from an unseen void it got soaked up by the MDF casing of one of my tool cabinets, the floor regularly flood from a leaking window yet that cabinet which by now should be a soaking wobbly piece of cardboard is as rigid as anything.

3 years on and there is still no sign of rising damp.

I have no idea if the silicone creams actually work, the cynic in me says that they had to come up with something now that no-one is allowed to transport the white spirit stuff, the creams cost nothing to produce, a couple of silicone tubes compared to a 20 litre drum of petroleum product and cost next to nothing to deliver, they dont need expensive powerfull Equipment either, what more could an industry that is not concerned with stopping damp but selling hope and worthless guarantees ask for?

 

[Quillan]

Just as a matter of interest reading the first post it says that the house is in a terrace, is that end of terrace or are their houses both sides and if so does the second house suffer any problems?

[dave21478]

Might be a silly suggestion, but what has your weather been like lately?

Here we have had the longest, wettest period locals can remember for many, many years, leaving the ground completely saturated and there are an awful lot of problems where water has got to places it wouldnt normally.

Perhaps this is a one-off in your case?

[Théière]

Good morning, my use off the damp cure creams is on regular brick walls and not stone.  On the brick walls it has been 100% successful after 5 ish years.  My Mother's house where I first used it is still completely dry above the damp course and another done a year later near Dover I was called to last month as they thought it had returned but it was leaking rainwater pipes (hence why it was upstairs) so I like it but in stone You'll need to be careful to get full penetration all the way through (nearly all the way).

There are water proof plaster type products like Izonil  which I have also used successfully on a development near the Battebridge basin on the Thames near Kings Cross,  Another company near me sell a similar new product and I have seen first hand how good it is at holding back water but allowing air to pass through.

As Dave said, what has the weather been like, a while back in Caterham (on the hill) the ground was so saturated the rain water gutters and down pipes were  full and causing damp everywhere.

[Chancer]

I did a day trip back to my UK place last week and in my 30+ years of ownership I have never seen such saturation and surface water, it must be time for another hosepipe ban [:P]

Here in France this is the first winter I can recall where there has not been ground heave in my courtyard, normally the block paving swells up like a balloon and it feels like you are walking on one, I dont think it has been any milder, perhaps the temp has been going above zero each day, or maybe the soil is unusually dry this year.

If you have blue clay Under your property a water leak from quite some distance away but oh so slightly uphill can spring up Under your feet, its impermeable and the layer often runs pretty much level.