Dampness advice needed.

@thatched cottag wrote:

Hi folks Im just new here tonight. Im looking for some advice if anyone here can help Id much appreciate. Looking for direction on damp proofing and old stone thatched cottage which is in reasonable condition. The cottage is white washed on the outside seems to be on pretty thick, probably over a long period. Inside walls dont seem to have dry lining, only evidence of dampness is flaking paint on lower walls in most rooms. One room in the cottage is a wooden floor which I intend to replace with as concrete floor, the rest of the cottage which is three rooms have concrete floors, unsure if damp proof course has been installed. There seems to be alot of damp proof products and experts out there but what systems/products are sure to work. The walls are maybe 2 feet thick , old stone so drilling could be difficult. By the way the thatched roof is in reasonable condition so it is not a problem at the moment. Single glazed steel windows will be replaced with wooden double glazing. Oh did I mention that the old budget is v tight.

I suggest you take a look at http://www.periodproperty.co.uk which has lots of practical advice for this kind of building. In simplistic terms, the walls of a building like this are designed to be water absorbent, releasing moisture to the atmosphere when it is dry, absorbing some when it rains. What often happens is that the original lime covering is replaced with an impermeable cement render. Over time this render develops cracks which allow water in without allowing the walls to dry. The water ends up working its way into the interior where it is then hidden with dry lining. I sincerely doubt that a DPC will be of any benefit to this kind of construction,

Hi thatched cottag

It is well nigh impossible to install a modern dpc in a stone wall as you describe. A Tintpretto says the wall works by absobing moisture and drying out again before it penetrates. As you intimate the dampness is probably rising damp. You should check relative ground levels. does ground level rise up near or above floor level and so on? After that the only sensible and cost effective way to deal with it is to accept and manage it by dry lining. You may not have to dry line the whole wall for instance. Be careful with your new concrete floor. Quite apart from all of the extra moisture you are introducing as the concrete dries out, watch the levels abd make sure you have a dpm in it.

good luck
BQ

Hi,
My house is a Georgain 2 storey over basement , the basement is of a random stone construct, the levels above are brick. The damp people that I had in from the Golden pages told me to inject the walls to create a DP Layer, the other told me to put an electric current running around the base of the walls in the rooms.

When I pointed out that you cannot acheive a consistant Dpc layer with random stone the guy told me I was wrong. The electric current thing is meant to be a gimmick.

So I put in a concrete floor with the standard plastic sheeting(dpc) beneath it. I hacked away all the soaking cement render – I think a 1950’s tanking solution. The internal walls were battened and plaster boarded. the external wall was drylined and the cavity vented to the outside. I put holes with radiator cover mesh in them into the skirting to permit warm air from the room to take away the misture from the base of the walls. Venting into the house is not the best, but it is better for the house than keeping the water in the walls, rising to the upper levels.

It was almost free but a bit risky. But the theory is Heat and Ventilation are the key to dry walls. Most people will advise you to spend a few thousand on it. It is hard to get expert objective advice because people are selling solutions. Its been fine for 2 years now . . . . .
But I don’t know what the survey would say about my homemade solution, if I try to sell. But currently I don’t have a damp problem. I don’t know what the little hand held damp reader will say though.

Check out this link: http://www.askjeff.co.uk/content.php?id=3

Hi,
the problem you talk of is rising damp and it is down to the fact that you have put in concrete floors. This is one of the major problems people have when they take on old houses. They may point the walls with lime as they are supposed to but don’t know that the floor is as important when it comes to moisture. The damp under the house naturally rises upwards and where there is a lime floor (use 5NHL LIME) the water is taken in and released when the damp is a little less, but in a concrete floor the damp has nowhere to go because the concrete does not take it in, so the damp goes outwards and then rises up into the walls. this will still happen even if you have dpc under you concrete floor. The best, cheapest and easiest way to fix this is to dig a trench of about 6-8 inches deep along the walls inside the house and put down yellow perforated pipeing which is very cheap and you can get it any farmers store. you could also wrap this pipe in breathable dpc, this stops any little particals entering the pipe but allowing moisture in. Then at some point along the wall put a hole through to the outside. This will carry off any dampness and vent the floor as well if you come out above gorund level outside. Insice the house, cover the pipe over and the trench in with lime or cement and when it dries you’ll never notice a thing but your damp will be gone. Also never dry line an old stone building, use 2NHL lime to plaster the interior and mix hemp through it which is brilliant at retaining heat and can hold heat in a room longer than most fancy products around today. You really should have put down lime for the floor but if you do as above you should be ok.

I have a similar query regarding dampness, new house with underfloor heating, spots appearing on bedroom and poarch walls. I wonder is this due to poor insulation in walls or condensation. Also windows are damp.