Buying a house, survey has reported damp...

[oversteer]

Hello all, first post.

I am in the process of buying a Victorian cottage built approx. 1890

The surveyor has pointed out that a flank wall has become damp due to water dripping down from a cistern overflow.

That drip has been fixed, but the solid wall is damp through to the interior. The exterior is rendered (not sure what with, looks like concrete?) and painted with "waterproof" paint. The rendering has some damage where water has dripped on it for a very long period of time.

The survyeor has said that plaster and render may need to be removed in order for the wall to dry out. Flank wall, so quite a large area, half the outside flank area and one room inside. Told to budget £4,000 for works.

I would normally expect something like this to be resolved before completion - but then, I gather expecting a solid wall to dry in this time is unrealistic.

Would it require the render outside to be removed to dry, or just repaired where damaged and let summer take its course ? I'd hate to have to run dehumidifiers when moving in too ..

Any pointers would be much appreciated.

 

[MdB]

Bump to get this back at the top (first posts don't show up initially so end up dropping down the rankings)

Yes a damp wall can take a long time to dry out. One inch a month is often quoted but it could be more or less depending on your wall construction. To measure the dampness properly, a sample needs to be taken from within the wall. Two prong meters can be misleading.

With the inside plaster removed (I assume its modern gypsum with unbreathable paint on top) then that will help as will removing the outside render. The more you do to allow it to dry out the quicker it will. In the longer term though, getting rid of the cement render (if that is what it is) is something you ideally will want to do. It has been 6 years and I've yet to remove the final section of cement render from my house but it will be coming off this summer. The wall inside was very damp but removing the render/plaster/dry lining on the inside was enough to let it dry out. The surface dried out within days so it wasn't a problem to live with whilst it was drying out more fully.

 

[AMc]

If there are no other problems with damp then I would be tempted to attempt to negotiate with the vendor for the likely cost but not to rush into anything in remedial works. While cement render and gypsum plaster aren't good my house has both in places and no damp problems. If it is possible to live with the drying wall and the plaster isn't destroyed then I would probably allow it to dry naturally.

I would want some reassurance that the toilet cistern overflowing was the only source of damp. It sounds like a lot of damage but I know that small leaks can cause serious problems if left unchecked.

If you're new to old houses then the best advice is to think and plan a lot before you start to act. It's very easy to start hacking things out and ripping them off only to discover the better course of action would have been to leave them alone.

Good luck with the purchase and welcome to the forum.

 

[MatthewC]

I agree entirely with both the above responses. Especially, it really is so important to make sure that all sources of dampness are found and fixed. My house has 18" thick walls and had dampness everywhere when we bought it in Oct 2010. There was an awfully leaking roof (slates, ridges, flashing), blocked/damaged gutters (partly due to ivy), damaged downpipes, blocked drains, a hole in the internal bit of the soil pipe and higher ground outside. Various attempts had been made to sort dampness with cement on walls but all that does is to drive the damp elsewhere, so we took all that off and re-plastered.

Inside was drier and warmer than outside by March 2011, we moved in during July and the subsequent movement of wood vs new plaster and paint indicates that it was still drying out when we put the heating on in November (which was also when we sorted the last bit of high ground). I reckon it is now dry but who can say? See my blog (http://houseintheenchantedforest.blogspot.co.uk/) for the whole story!

Don't try to fix everything in a rush - tackle dampness/water ingress as a No 1 priority, and accept that it might take ages before you can call it finished. :shock:

Best of luck - you'll find lots of good advice on this forum, and check the FAQs.

Matthew

 

[Zebra]

£4000? Blimey! Are you sure? To remove some render and some plaster? What did that include?

 

[oversteer]

£4000? Blimey! Are you sure? To remove some render and some plaster? What did that include?

This was an estimate of costs from our surveyor. I think it included removal and rerendering a flank wall (which will require scaffolding etc)

 

[oversteer]

The plot thickens, after another visit..
Another wall in another room has visible signs of damp, and was wet to the touch! This, even though the property has been empty for about a month. Slightly concerning, especially as it was the party wall..
I can see a lot of replastering work happening if we go ahead with this..

 

[Moo]

I can see a lot of replastering work happening if we go ahead with this..

First rule of dealing with damp: remove the cause of the damp, and only then do further works.

 

[Andrew Bodenham]

Hi, Oversteer, and welcome to the forum,

There are many possible causes for 'damp' in buildings, some not very obvious. Leaking rainwater goods, leaking roof covering, leaking flashings, leaking pipework, penetrating rain, surface condensation, interstitial condensation, high ground levels, drain problems, capillary action, hygroscopic salts, poor pointing or rendering, lack of ventilation.........

In unoccupied properties condensation can occur due to a lack of heating and ventilation. This may resolve on occupancy.

Think of your (potential) house as the elderly patient who presents at the doctor's with non-specific abdominal pain. The first requirement (before the patient even enters the room) is for the doctor to be well educated and experienced in treating humans i.e. not a vet or a plumber. Then there's a lot of careful history taking. Then perhaps some tests. Then a management strategy is developed, which may include doing nothing and seeing if it gets better. Surgical intervention would likely be a last resort rather than the first option.

Old houses need a similar approach. Immediate surgery is rarely required, but often recommended by surveyors, valuers, builders and others who work in the housing sector, especially if they lack real expetise in working with older properties. Many interventions are inappropriate and a waste of money, in some cases introducing new problems or causing collateral damage at a later stage. You have to be strong in standing up to institutions like building societys and bank which do not have a clue about property technology but are far too ready to listen to 'experts' who have a product to sell e.g. damp-proofing, timber treatment etc.

All I can really suggest is that you do a lot of reading and research around the subject, or employ an architect, architectural technologist or building surveyor who holds appropriate accreditation in conservation practice to guide you. Many people run shy from paying for advice, but it could put you in a good negotiating position and save thousands in the long run. And poor old Mr Bowel might be wise to seek a second opinion from another consultant before submitting to major surgery.

 

[MatthewC]

There are many possible causes for 'damp' in buildings, some not very obvious. Leaking rainwater goods, leaking roof covering, leaking flashings, leaking pipework, penetrating rain, surface condensation, interstitial condensation, high ground levels, drain problems, capillary action, hygroscopic salts, poor pointing or rendering, lack of ventilation.........

In unoccupied properties condensation can occur due to a lack of heating and ventilation. This may resolve on occupancy

Another wall in another room has visible signs of damp, and was wet to the touch! This, even though the property has been empty for about a month. Slightly concerning, especially as it was the party wall..

Or precisely BECAUSE it has been empty for a month and therefore probably less heated and less ventilated, as Andrew says above?

You won't want to worry about re-plastering until you have tackled the causes of dampness (I'm going like Feltwell, I'm repeating myself....)

 

[oversteer]

Yes this makes sense and maybe I'm just being paranoid!

We have booked a specialist who has experience with this sort of property for a fee-based inspection and that will decide on our plan of action.

A local company submitted a quote after a "free inspection" yesterday! :lol: I think they send the same quote to everyone. Injected DPC everywhere!!

 

[oversteer]

I am a lot happier after receiving the second report, from a damp and timber surveyor.

There are still quite a few issues that need resolving, but a lot of the mysteries that the full survey introduced have been explained. Most seem resolvable with improvement of airbricks and gutters and so forth.

He recommends stripping away the external render and redoing it, introducing a "bell drip" above the slate dpc and waterproof paint below.

Interestingly the dampness in the kitchen is possibly explained by a former fireplace that has not been treated properly, and something related to coal dust and ammonimum salts. Looking at a satellite photo, there are chimneys in the other houses in the terrace in exactly the same position as where one in this property has been removed, matching exactly where the worst of the damp is, so possibly this is where the range would have been originally?

So some extra costs that we will talk to the vendors about, but nothing too disastrous and hopefully we can do some good when we move there!

 

[Feltwell]

Move forward with caution I would say, in terms of what work you do once you've moved in.

IHe recommends stripping away the external render and redoing it, introducing a "bell drip" above the slate dpc and waterproof paint below.

A bell drip sounds sensible enough (it will make whatever rainwater runs down your render drip away from the exposed brickwork below) , but "waterproof paint" below? No - a very large No in fact. Trying to seal damp out like that just doesn't really work. Much better to manage it so that the building breathes, rather than trying to seal it. Also why try and seal below the DPC? It just doesn't make sense.

Sealing a wall just means that whatever moisture you have inside the house struggles to escape - and you will have plenty, from breathing for starters! Sealing the outside never completely stops moisture getting in either, it just traps most of it once it is in.

Stripping the render sounds sensible enough, but is he saying to re-render it in cement-based render or a breathable finish? If he's just said "re-render" then from his other comments I expect he means cement-based, as most builders would still use. A breathable lime-based render, with a breathable paint finish over, will allow the wall to dry. If the rest of the house is rendered in cement and is dry - which is quite possible - and you don't want to re-do the whole place (who would?) then you could patch that area with lime render and look for a breathable paint finish that will cover both surfaces. I think silicate paints will do this - not sure though, others on here have used them, I haven't.

 

[MatthewC]

Stripping the render sounds sensible enough, but is he saying to re-render it in cement-based render or a breathable finish? If he's just said "re-render" then from his other comments I expect he means cement-based, as most builders would still use. A breathable lime-based render, with a breathable paint finish over, will allow the wall to dry.

And don't be misled - if your builder says he will "use lime" he might just mean a 6:1:1 sand:cement:hydrated lime mix, which is NOT breathable; it just gives a more lime-like finish. Frankly there is a stunning lack of understanding of lime, dampness and breathability amongst the vast majority of builders - you have to explain what you want and why. If you have a builder who DOES understand, hang on to him!