treat damp in 1895 cottage

[senorjackson]

We are in the process of purchasing a Victorian house (1895) in the East Midlands. The survey has highlighted damp in the walls of the ground floor and has suggested the usual injecting of the walls after taking off 1 metre of plaster on each wall. The floor of the lounge and dining room ( in each room the damp is deemed to be high- in survey, levels of damp detected went off the scale) have solid concrete floors though I doubt these are an original feature. I don't know whether they have a dpc membrane. Might it be that damp in the floor, unable to escape, is spreading to the walls? Other points to be taken into consideration:-
1. The house has been vacant for at least 6-9 months
2. The back of the house backs onto the road. I don't think the internal level of the house is much higher than the road itself but can't be exact.
3. House has been deemed to be fine apart from this issue.

Having read through the forum, I've posted this as I haven't been able to find a precise answer to solve the damp. I would gladly welcome any advice on how to treat this successfully, as I am unsure if we should move in and see how things go or look to try to sort things out before we move in. Is there an easy answer?

Many Thanks

senor

 

[Moo]

No real advice, I'm afraid, but a few questions that will inevitably be asked:

What sort of plaster and paint are on the inside of the walls?
Is the outside of the house unpainted brick?
Is it rendered/pebbledashed?

Sorry not to be more helpful, but at least this will have bumped your question back up to the top of the list.

 

[senorjackson]

Many Thanks,

Outside is a combination of local stone then traditional brickwork. Internal walls are have wall paper or painted. No render pebbledash on external walls.

cheers

senor

 

[Penners]

If the house has been empty for 6-9 months, and the damp reading was taken in winter, I'm not surprised that it revealed damp. I can't see how this can be regarded as a true measurement of the normal damp level in the walls. Condensation is almost certainly a strong factor in the reading.

You talk about "the survey", but who did it? Was it a properly qualified chartered surveyor, carrying out a full structural survey for you, or was it a building society valuation survey? Or was it a damp treatment company?

I'm not saying that the house isn't damp. Obviously nobody on this forum can confirm or refute that fact. But I am saying that there's a risk the readings were considerably skewed by the weather conditions and the fact that the house has been unheated for many months.

The concrete floors are likely to have forced damp to migrate to the walls, regardless of whether they have a dpm or not. And I have little doubt that you will have to end up hacking off the plaster up to a height of 1 metre or more. But I urge you not to forge ahead blindly with an injected dpc. You need to take the situation a step at a time.

I would certainly start by hacking off the plaster as recommended. But then give the walls some months to really dry out. I assume that you will be living in (and therefore heating) the house shortly, so this will give the drying out process a good start. But don't be in too much of a rush to replaster - no matter what the inconvenience. If you can stand it, leave the walls unplastered until warmer weather arrives, and then re-assess the damp situation.

Meanwhile, have a good look at other possible damp sources - gutters, downpipes, leaking pipes and so on. Make sure that everything else is in good order, so that when you do start to replaster, you're not just covering up a continuing problem.

 

[Lime]

senorjackson, have you read through this link?

http://periodproperty.co.uk/forum/viewtopic.php?f=6&t=6777

 

[senorjackson]

survey carried out by chartered surveyor.

Regarding the concrete floors, could they be the cause of the issue and what could be done to alleviate the situation?

Cheers,

Senor

 

[JoceAndChris]

I really strongly recommend that you buy this book:
http://www.amazon.co.uk/Old-House-Handbook-Practical-Repair/dp/0711227721

and read through the excellent chapter on damp. The other chapters are also wonderfully useful. I wish I'd read it before purchasing.

Concrete floors aren't good news, I've got some and they do indeed push the moisture into the walls. I manage this by dehumidifier, increased heating in that area, and more thorough ventilation - as well as by avoiding things like drying laundry indoors, wherever possible. This has greatly reduced the symptoms of damp, though the underlying cause is still there unfortunately.

If you really wanted to create a breathable floor you could do it with limecrete, but it's expensive.

We also resisted the scare-mongering of DPC merchants who found high levels of moisture and wanted to hack off all the plaster. The house hadn't really been heated, now it is things are a hundred times better.

Good luck!

 

[senorjackson]

Thanks for that, I'll definitely have a look at that!

 

[Hatster]

I'd like to second what the others said - I've found that damp is much easier to manage than surveyors will usually tell you. Just heating our house properly and consistently, getting the air circulating, and lowering ground levels outside had made a big difference. The SPAB book and this forum has many an answer!

 

[Andrew Bodenham]

I agree with the sentiments expressed so far by other posters. 'Damp' is a very subjective thing, and damp meter readings are not really very helpful in determining if the dampness is problem. They do make a surveyors report look more impressive though, and might give you some leverage for knocking down the vendor's asking price.

Don't rush into any 'treatment' of this supposed problem. See what occupation, heating, ventilation and a hot summer (no promises there, alas) will do before deciding a course of action, and then only after getting good advice from somebody with real expertise - a conservation accredited architet perhaps. Our house was very soggy in parts when we moved in, some areas took a long while to resolve, but generally it's down to heat and ventilation once basic physical causes have been fixed. If, in a couple of years you find that your wallpaper won't stick, or that one corner is always growing mould, then you may have a damp problem. Until then resist all the nonsense talked by mortgage companies and builders.

 

[Flyfisher]

This book is also an interesting read: http://www.askjeff.co.uk/rising_damp.html

There are, of course, many other causes of damp than just 'rising damp'. However, one thing that did hit home, for me, in that book was the section on injected DPCs. It was pointed out that, regardless of any arguments for or against, the typical installation is almost always flawed. This is because the time that is actually required to fully impregnate a brick wall with a water-resistant liquid, is - according to the book - far, far longer than the quick "squirt" into a drilled hole that is used by typical installers.

I'm certainly no expert in any of this but it seems intuitively right, to me, that to fully impregnate a course of bricks with some sort of liquid would be a major undertaking and would take quite a long time. Any pressure that could achieve such penetration in a few seconds per drilled hole would - I suspect - surely have to be so high that it would likely blow the brick itself apart.

On a more practical note, what about the neighbouring houses, if any? If they are of identical/similar construction then it is probably worthwhile talking to a few of your potential neighbours to see if they've had any damp problems. This might reveal if there is a fundamental problem with the property design/construction or if it is just suffering from a period of unheated emptiness.

Good luck and do, please, keep us updated.

 

[christianb]

The problem with injected chemical dpc's in anything other than prescribed materials (breeze block, london brick, etc) is that you will never achieve a uniform layer of resistance. And the chances of doing so in a coarse rubble stone wall begin at nothing and taper off.

All that will occur is that certain parts of the wall will be bone dry, while others are wringing wet where the moisture has found a way up. Moreover, there's little doubt in my mind that your concrete floor is likely to be shoving some of the damp up the walls. But even if you remove the concrete (nice job... not) you'll still have damp in your floor.

As others have said, let the place get an airing and you'll be surprised how the problem begins to diminish.

C.

 

[Matt Green]

The floor of the lounge and dining room ( in each room the damp is deemed to be high- in survey, levels of damp detected went off the scale) have solid concrete floors though I doubt these are an original feature.

Workmen. Tools.

No, the damp detected didn't go 'off the scale' the electrical resistance meter used by the surveyor showed very low electrical resistance in some areas which he has attributed to damp, one cause of low resistance readings.Have the rooms got foil-backed wallpaper (you'd be amazed...)? That obviously causes readings that are off the scale. Other confounding readings can be given by lime plasters, salt contamination of plaster and surface condensation.

The scale itself isn't the important part either: it's the pattern of the readings that gives you the diagnostic information, not the individual results. If the readings do drop off after a metre then there might be water moving up through the base of the wall and the concrete floor might be part of the problem. A condensation pattern would be less likely to drop off after a metre. However, walls with ground water in them might still be colder so condensation might exacerbate another problem. If the surrounding ground levels are too high (they should be 6"+ lower than the internal floors) then that is the source of the problem, and those levels need to be reduced.

But really is it causing much of a problem? Are decorations being spoiled? I'd certainly live with it for a while and see what happens. Damp would never stop me buying a house, it's always fixable, but 'damp-proofing' is a good bargaining chip when it comes to arriving at a final price. If you are that way morally inclined.

 

[senorjackson]

Many Thanks for all the advice written above but if you do have any more ideas, please feel free to list them.

Thanks

Senor

 

[TimM]

Is sorting out the damp a condition of the mortgage? It was for us, but it did, as has been mentioned, act as a good bargaining chip. In the end we had to get some re-plastering done (although nothing as complicated as the surveyor suggested), the mortgage company sent someone round to look at the work (and all the other things they made us do) who turned up two hours late, didn't look at anything, asked if we were pleased, released the retention and went for his lunch...

 

[senorjackson]

It is a recommendation and the mortgage is not dependent on it. Unfortunately tried to bargaining on price but they didn't take it and we'll have to foot the bill if we need to.

Thanks

Senor

 

[Lozzy-May]

We had a similar issue when we purchased our 18990s terrace. We did a survey and so did the owners and both surveys highlighted damp in different areas i.e. they didn't match up at all. There were no obvious signs of damage due to damp - no mould on walls, no rotten wood etc. - so we went ahead with the purchase. When we moved in it was July so we were able to have the windows open to air the house which helped considerably. The musty smell went completely and we were happy not to put in the expensive DPC course that the surveyor recommended. We've now been through a very cold winter and a few moisture issue have arisen, particularly when cooking in the kitchen. A lot of moisture condenses on the walls for example because the outside walls are not insulated. It has nothing to do with rising damp or anything like that, it's just cold walls. Our thought is that insulation is the answer, not a DPC injection. We've already put down extra insulation in the loft, which has helped. At some point we will look at getting insulation for the walls. There are some products which you can attach to the internal walls that are very thin, good insulators which you can paint straight onto. The other thing is to check there is good airflow through the airbricks and under the floors.

 

[senorjackson]

Many Thanks for all the helpful replies and advice once again.

Senor

 

[senorjackson]

Hello there,

we are about to complete on above property in next weeks and I'd like your opinions about the worth of getting hold of a dehumidifier to make a start on the damp. How helpful would it be? Many Thanks in advance,

Senor

 

[Flyfisher]

This type of thread always makes interesting reading.

I'm certainly no expert, but my conclusion from personal and others' experiences is that 'damp problems' are, in many cases, a result of a mismatch between modern expectations and period construction methods. In short - ventilation vs insulation. We all know that older houses were not well insulated and that open fires were the only form of heating. Even if doors and windows were tight-fitting and draught-free, open fires are notoriously inefficient in pure heating terms but wonderful devices for moving air out of the room, albeit heated air, and replacing it with fresh, albeit cold, air! Thus, any dampness, whether 'real' or from internal condensation, would likely be quickly evaporated and expelled through the various chimneys in the house. Plus, the amount of internal condensation would likely have been much less than in modern houses because average temperatures would probably have been lower (cold air holds less moisture than warm air) and daily baths and showers were also not exactly commonplace.

Fast-forward a few hundred years and the emphasis is on comfort, convenience and efficiency. Central-heating systems keep the entire house at a comfortable temperature, whether the rooms are occupied or not, and hot steaming water is on tap - literally - in multiple bathrooms as well as the kitchen. High average temperatures throughout the house means that much more moisture is held in the air ready to 'rain' on any cold patch of wall or ceiling. All of this is fine if the property is newly built with such things in mind, but retro-fitting them to a few-hundred year-old property is where the problems start, often because of the urge to eliminate draughts and improve insulation, thereby minimising or eliminating ventilation - with the inevitable results.

Based on all this, I think a large part of the answer to 'damp' in old properties is, frankly, to accept it. I don't mean we should put up with mould growing on the walls and fungus crawling through the carpet but that we shouldn't immediately panic and reach for the silicone-this, DPC-that and magic-waterproofing-spray-on-other 'solutions'. Try opening the windows and let the fresh air waft through the house during the day (even cold air will have a significant drying effect) and wear an extra jumper in the winter instead of trying to emulate your last summer holiday all year around.

A old house won't 'perform' like a new-build, and can hardly be expected to, so a little bit of give-and-take will work wonders. Call it sensitivity if you like. Many people, of course, will disagree with such an approach, and that's fine, but it might be worth asking if a period property really is their sort of ideal home.