Damp in old house

[matthe106]

Hi this is my first time on here any I just want some advice on a new house I have moved to,

I live in a old farm house and one of the exterior wall has previously been rendered, the render is now breaking off and the inside walls are now damp, my plan is to strip the old render off and clean up the mortar, re point it if I have to and then clad the exterior with timber, I also plan to put a stud wall on the inside were space is tight with a damp proof membrane, the questions I have are:

What should I use in side as a damp proof membrane I have done a lot of research but one of the builders I have had in said he would put thermal foil insulation in to save room and that it would act as a damp barrier, I wanted to know if that would actually work ?

Secondly can I do the inside stud wall ect before I do the outside work. Or should it be completed after the root problem has been solved.

And with the exterior of the house once the render has been removed, if the mortar in the stone isant very good would it be a bad idea to leave it and just clad over it obviously leaving an air gap

And in all would this stop the damp.

Thanks

Matthew

And just thought of something, would removing the old render now be more damaging then good, I just thought maybe its holding water and if it was taken off even in the wettest weather wouldn’t the stone at least dry off rather then be wet constantly?

 

[Graeme1983]

My first post too mate, Im also on here looking for info and second opinions on restoring an old house. Ive got a bit of knowledge from other sites, books and some local old hands. Im a year into restoring(and living in) an old miners cottage in the forest.

Ive been coming up against the same issues. My house which is built out of a clay/earth brick originally in the 1890's and would have been painted/rendered in lime has been rendered in cement and a concrete floor and paths put in during the 80's. It wasnt lived in properly since the 70's so when the sale was happening the windows had been left open and no condensation from people so it seemed fine but when we moved in the damp has been coming out from breathing, cooking and showering etc and a very wet summer. We knew there would be trouble but the location was the deciding factor.

From research and experience so far, the way forward is by going backwards. Return to the original materials. Im part way through destroying the concrete and render all by hand to be gentle on the house, (half of it is crumbling away anyway, what it is, is that the moisture has nowhere to go on these new waterproof methods shoehorned in so its rots and pushes and crumbles through the concrete/cement wherever a weakpoint is an old fashioned porous material would gradually let the damp out evenly). After which Im thinking of either rendering in lime and a limewash finish or limewash directly onto the bricks(the tests so far on outbuildings look good) and Im also putting in a French drain. Just by removing the concrete path outside and letting the bottom of the house breathe again we seem to have fought off the damp.

My advice for you to look into:

1. If the External wall render is cement and not lime, take it all off, repoint in lime mortar. Consider chipping off the inside wall render if its cement and re-render in lime with a limewash finish.

http://www.periodproperty.co.uk/shop/acatalog/plastering_with_lime.html
http://www.projectbook.co.uk/article_11.html

2. Dig out a French drain, gravel with drainage pipes to run the water off. Im building a complex one and trying to be a smartarse using the run off to irrigate my veggie plots, but even the early stages has really fought off the damp.

http://www.ihbc.org.uk/guidance_notes/docs/tech_papers/French Drains.pdf

3. Cladding in wood should be okay but be careful if your thinking of insulating it. Think of using a breathable version like sheepswool or hemp, not the waterproof modern sort of stuff. Old walls are usually much thicker, mine are 80cm thick on the most part and absorb and release heat from the woodfire, insulation isnt needed in my case, it might be the same for you.

http://uk.sheepwoolinsulation.com/why_wool/

4. Be careful of waterproof damp-proof membranes. I had the older version in tar paper. It just traps the damp so the walls sweat and damp/mould accumulates in the corners. Look into geo textile breathable fabric. Foil seems too waterproof to me.



Basically the key words are breathability and ventilation. Would the farmhouse be listed if its in the UK? If so you should have conservation officers who can advise on methods and local resources.

 

[matthe106]

Thanks a lot for replying,

First off I completely see what you mean about allowing the building to breath,

So If I use a breathable membrane on the exterior and clad it leaving an air gap and then use a breathable membrane insulate it on the interior and then use a moisture shield plasterboard on top with a air gap this should allow the building to breath but also stop any damp/moisture penetrating in to the rooms.

I don’t think that the drainage is a problem because you can look at sections on the wall that are falling away ect and match them up with the problem walls on the interior and most of them are upstairs

Do you think I will need to dry the wall out before doing any work to it and do you think I would just be asking for trouble if I pulled the render off and left it off over the winter,, the render has separated from the stone and I think It may be creating more of a problem.

thanks

 

[Graeme1983]

I think that sounds okay, Ive only cladded my old shed so can only come at it from the lime rendering/mortar/re-pointing perspective but air gaps and breathable materials are on the right track. There may be some other topics on here that are good, the carpentry and garden topics where people are making deluxe sheds and garden offices.

Have you not considered just lime rendering over the exterior walls? Even after that I think you could make a wooden frame with battens to clad over the wall cosmetically. It should be a limewash outside, lime render over the stone or brick walls, then inside another lime render over the brick walls with another limewash coat. Personally I wouldnt use any plasterboard or waterproof material, I wouldnt want to trap the moisture anywhere and would want the lime to do its job by being porous and breathable and regulating the moisture.

Personally I would let the wall dry out over winter. I am before I get on with the lions share of my limework. Lime rendering and plastering should be done externally in the spring or summer anyway, it shouldnt be done in the winter as it wont dry so its an enforced waiting period anyway.

Id chip it off to let it dry over the winter but it may be worth asking for a second opinion.