Maybe a slight exageration but it feels like a hell hole at the minute.
We completed on our new house last week. A late 1800's cottage (used to be one very big house split at some point in its history). The rear of the property (the kitchen) has a single skin construction on the outer wall. We knew this when we bought it and new there would be some issues along the way. However, we didn't quite expect the monumental amount of rising damp that has left the concrete floor wet to touch, the woodwork and much of the plaster work rotten and the house stinking like a the inside of an old washing machine.
We have completely stripped out the kitchen. Knocked all the plasterwork off the walls and dug some trenches outside the back walls where we believe the damp issue is starting from. There is no water proofing to the external walls or the concrete floor and the fools who owned it begore buitl up their patio and garden beds above the floor line to the house. We are hoping that combination of things is the route and that we can remedy the cause externally.
However as the kitchen is stripped out i want to be extra safe and do something with the floor to prevent damp rising again, particularly into the plaster and woodwork. I've seen sone products that are like a more advanced version of bitumen that you apply to the top of a concrete floor which act as a damp proofing membrane which you can then lay your chosen flooring on top of.
Can anyone offer some general advice or info on products etc?
Can you afford to get a few decent builders round? They'll be able to offer advice.
Paint on products just trap the moisture in. Fix the issue dont just treat the symptoms.
Get the patio away from the wall , get a french drain in along the exterior drawing the water way
The wall hasnt been rendered with cement or similar has it ? Nor repointed with cement based products ?
Isn't the survey supposed to pick up on stuff like this?
Surely the previous owners knew about this... so aren't they liable for the cost in some way?
Surveys can pick it up but depends on whether it was a full survey or a homebuyers report. The report just points out where there could be problems but doesn't actually look into anything in any detail.
Don't get companies in that advertise as doing damp proofing, they'll just reel off a load of what they think you want to hear and more often than not charge an arm and a leg for it. We had damp in one room but a damp proofing chap insisted on checking the whole house then came up with a quote for £3.5k as he said there was damp in 3 other rooms. Problem was solved by removing a flower bed that was trapping water against the house and replacing a blocked airbrick.
Old building, no foundations, modern materials are likely the issue. A property that old would have been drafty originally, and would have been able to breathe freely. Build up the ground outside, put in concrete floors, modern plaster and start shutting up the drafts to keep the heat in also hold all the moisture in too.
With cold walls due to the old build, it's a fair bet that condensation from general living moisture is more of a problem than you think it will be, as well as the rising damp.
The wall hasnt been rendered with cement or similar has it ? Nor repointed with cement based products ?
The property is rendered (ye olde white cottage) couldn't tell you what with though. Don't think it is cement though.
Get the patio away from the wall , get a french drain in along the exterior drawing the water way
Yes, thats the plan externally.
Isn't the survey supposed to pick up on stuff like this?
Surely the previous owners knew about this... so aren't they liable for the cost in some way?
Well, they almost certainly knew about it and did a very good job of covering it up on viewings and we only had a secondary survey carried out to identify an issue with an extension. We had no knowledge of a damp issue sadly.
Old building, no foundations, modern materials are likely the issue. A property that old would have been drafty originally, and would have been able to breathe freely. Build up the ground outside, put in concrete floors, modern plaster and start shutting up the drafts to keep the heat in also hold all the moisture in too.With cold walls due to the old build, it's a fair bet that condensation from general living moisture is more of a problem than you think it will be, as well as the rising damp.
Yes, i suspect you are right. Finding the way to remedy this and allow the property to breath without being an icebox is the challenge.
What about something like [url= http://www.nuaire.co.uk/our-products/Residential/products?pt=1685 ]this?[/url]
Bitumen floor is your first call.
Then air brick/more ventilation. I'm not sure damp course injection would help here, you could possibly coat the internal walls too to stop the internal walls getting damp, but there is very little chance of stopping any water getting into the stone work.
Already mentioned is work outside to drain / stop up the bottom of the walls.
A good dehumidifier will help, in the short term, to make it a nicer environment to live in.
Old houses were built at at time when coal was cheap and every room had a chimney so massive amounts of air were drawn up and the house was well ventilated. Modern ideas of blocking any source of draft have caused all kinds of damp problems. Yours sounds terrible though. How much would it cost to try to remedy and how much to knock down and rebuild the entire extension to a modern standard?
If the damp is as bad as you say then I'd suggest that putting anything on the floor (like bitumen) won't work as the water pressure from below will just force it off over time. Tank it on the outside then the water force works in your favour. Difficult to do much under a floor without ripping it all out though.
Don't bother with bitumen on the floor. What is the floor made of? What you have to do is (and most of this you can do yourself) 1) remove kitchen. 2) dig out the floor to what ever is underneath, mud, clay, stone etc. probably about a foot down. 3) chip all the plaster off, which i see you have done. 4) have a damp course put in - which is essentially silicon injected into holes in the wall. Shouldn't cost you too much. 5) Put in any new plumbing and wiring that you need 6) have the walls 'tanked' which is a concrete waterproof type coating. That should be about 120 cm up the walls, depending on the extent of the damp. 6) sand on the floor, damp proof membrane (that's just plastic sheeting really) concrete, then a screed on the top. 7) new kitchen - yours is probably shot anyway. (Plan any new fittings around this installation). I've done jobs like this for 5k all in, in a an average size kitchen - including the kitchen. That's about the extent of it, besides redecorating, or putting in a stud with plaster board for better insulation etc. might be a few things that I've forgotten - but that's kind of what needs to be done if you want to if the issue - fixing the cause could be more costly, it depends on what's going on outside of the house. I've put in land drains, found cracked pipework etc to fix things like this in the past thou.
Tank it on the outside
Seconded. Certainly wouldn't hurt, if you can't resolve the main cause - on house I did in Bath had a natural spring in the garden a few doors up, we did that there, just in case.
Polythene DPM on the floor and new screed over. Vandex on the walls, up to about 1m then either re plaster or dry line the walls with insulated damp resistant plasterboard. Plus the external measures mentioned.
As shoefiti just described is the right way IMHO. I have just done exactly that on an 1880 cottage with the same problem. My only additional comments though is to make sure that you get a good layer of hardcore hammered into the mud /clay before you blind the floor with sand. It reduces the risk that the concrete slab could settle on one side if there is any settlement /drying in the ground.
Also the plastic sheet on top of the sand is more of a slip membrane to allow the concrete to contract slightly when it dries without cracking, it also stops it drying too fast by preventing the moisture being sucked away into the sand. I recommend that you put another specific damp proof sheeting on top of the concrete slab and then if you have the space (you will if you plan properly and dig out accordingly) add a layer of insulation (150mm of celotex or similar) before the screed goes on.
Wiring should be kept to the edges (above the insulation) but water pipes can be laid and clipped across the celotex before screeding.
The celotex will have a huge effect on keeping heat in; concrete floors are terribly cold otherwise.
Also make sure the top layer of damp proofing is folded up the walls to the top of the screed, particularly on the exterior walls and make sure you fold over and tape well on all material joints.
Best of luck.
I am tempted to excavate the floor. I think the severity of the issue warrants it. It's going to have to be a job I'm going to need to do myself though as we just didn't factor in this cost but with our first baby on the way I need to get ourselves a home sorted fast.
I know from digging the external trenches that half of the foundations are sandstone which predate the house so obviously there was some other building here long before the house. Because of the terrible patio and garden beds the clay below and around the foundation is saturated with water and we have areas of the sandstone foundations with fist sized cavities. No wonder moisture had found its way so easily under the house. We currently just leaving everything to dry and breath for a while and we'll take it from there.
As you have a bit of a deadline to work to, I suggest you think about getting a dehumidifier. Either buy a decent version, if you think it will be needed long term, or hire an industrial one.
Same story here … solid stone walls, high external ground levels, cement render and concrete floor.
So far digging about 100 tons of dirt away from the house and striping the walls back and repointing in lime has worked wonders. Next stage is to get the floors up and get a lime floor down so that the whole lot can breathe.
Dehumidifiers are essential in old houses, plus an Aga in an old farmhouse like mine.
Get a builder who knows what they're doing with traditional building techniques, and be very patient … the house will tell you what to do if you give it chance.
Id be very reluctant to go injecting pish in the walls and painting/sticking non breathable layers in, often does more harm than good by trapping moisture on the wrong side.
9 times out of 10 there is an external reason why its doing what its doing.
Farticus has the right idea if you ask me.
Lime is your friend in old buildings - gyproc and cement /concrete are not.
injecting pish
It's no different than the damp course on a brick house. It's done to prevent moisture wicking up and weakening the walls. You sure don't want that 'breathing' into your living space, especially with a little one on the way. Common practice on old buildings.
If increasing ventilation and retaining heat is the aim could a whole house great recovery ventilation system help? Would also help redistribute the heat from the STW standard issue wood burner when you fit it 🙂
Having renovated a house with damp problems in the cellar, I think Farticus gave you some superb advice:
Be very patient, the house will tell you what to do if you give it a chance.
"http://www.heritage-house.org/managing-damp-in-old-buildings.html"
Working in old stone buildings is different to reasonably modern brick buildings.
Personally I'd line the inside of the walls with Celotex, so that I had two layers of foil and some insulation to stop condensation on the inside. Accept that the wall will soak up and evaporate moisture on the outside.
I did a similar thing with my workshop, the walls are single skin concrete blocks which soak up water, but the inside is dry as a bone....
could a whole house [s]great[/s] heat(?) recovery ventilation system help?
That would not work.
You need to start with a sealed, pressure tested, envelope first, it would be like trying to store water in a colander.
Of on a slight tangent but I'm aware of the potential unhealthy implications that come with living with severe damp (particularly with a pregnant wife and subsequent baby on the way) so what sort of dehumidifier should I be considering?
It's hard to work out what's adequate or not.
That article about old houses is somewhat biased, but essentially bang on. Not much else to say. Capillary action can cause rising damp, which is why it's best to have impermeable foundations where possible, but mostly it's condensation from dew point. Because nothing can get out, it's just condensing on the coldest parts of the structure.
If you can tell the concrete has a DPM from your trenches, I'd not bother to break out the floor, its impermeable as it's going to get and doing all that work just to put some insulation down where it contributes the least savings isn't really worth it. I've never seen the point of a lime based floor going down so it can breath, it's only going to put moisture into the living area. From a heating demand point of view, concrete floors are typically slightly warmer than a suspended floor, they just feel colder on skin contact, which is relativistic anyway.
Ventilate and insulate in consideration of the buildings characteristics. There are down sides to internal and external insulation for old buildings so its worth taking the advise of a historical building specialist. It sounds like it's going to take a while to dry out, but if you decide to put a waterproof coating on the exterior of the walls, you'll never be free of damp living.
OP, whereabouts in the country are you?
Northants, border of Warwickshire.