drying a damp wall?

[jungle_jim01]

Hi, i'm in an ond yorkshire sandstone house. One of the 1st floor bedroom walls has damp problems....when i moved in the wallpaper was coming off due to the damp. I removed the wallpaper several months ago and am now in the process of repointing the horrible cement ribbon with traditional lime mortar. The damp was originally coming in due to a leaking gutter i think. However, 4 months on and after a few weeks of hot dry weather with the cement pointing removed (haven't repointed yet) the area is still damp to touch. I would have thought that by now it would be drying...any suggestions on how to dry this out would be really appreciated.

Many thanks

 

[worms]

I think time is the answer! I've seen others on here quoting a month for every inch of wall thickness.

 

[jungle_jim01]

Wow...ok...thanks for the reply...any thoughts on replastering?...i know there's been a lot of discussion about lime plastering...i'm considering doing a 2 day course and have a go myself. Does it really make a big difference using lime over ordinary plaster?

 

[christianb]

Hi Jungle Jim,

Afraid it's going to take a wee while to dry completely. Constant air circulation and ventilation will help, and I expect the summer to expedite things!

As for lime plastering? It's a wonderful material to work with, and if you feel confident... just do it!! First things is to put the scratch coat on, so if you feel good about that it should steel you for the finish coat!

Christian

 

[Flyfisher]

A leaking gutter can deposit an astonishing amount of water onto a wall. Few people go outside to watch their guttering and downpipes in the pouring rain but it can be an enlightening experience.

Assuming the wall had been soaked right through, I wouldn't be too concerned if it was still showing some signs of dampness after 4 months. The construction will make a big difference to the drying out time but it sounds as if you've done the right things so I'd just maximise ventilation for the remainder of the summer and monitor how it gets on. It will help things if you can delay replastering - even lime plaster will (I think) slow down the rate of drying out.

All this assumes, of course, that the gutters are no longer leaking!

 

[jungle_jim01]

Thanks for the advice...yeah the gutter's fixed. I haven't yet pulled off the plaster...debating whether or not to bother...We're basically renovating the property with a view to selling on in a few years time. Obviously lime plaster would be in keeping with the original features but i'm wondering how much difference it will actually make to the building and if i can just skim with modern plaster??

 

[Penners]

If you've fixed the source of the damp, and you're sure that there are no other unseen problems lurking, then you're part-way to seeing the end of the problem. As others have said, you now have the (rather long-winded) job of drying out all that damp within the structure.

Fortunately, this is a good time of year to be doing it. So don't waste any time in exposing as much of the sandstone as you think necessary to the warmth and fresh air. Don't be tempted to skimp on hacking off any plaster and cement - make sure that all of the damp area is exposed.

Depending on the thickness of your walls (and yes, I've also seen the rule-of-thumb quoted by worms above), you might manage to get rid of the damp in a few months. It's then definitely worth plastering internally with lime.

 

[jungle_jim01]

thanks for all the advice. I think we'll pull off the old plaster and re-plaster with lime. But i'm wondering what the finish is like...i dont think theres a need to do the internal stud walls but i'd like the same colour finish around the room...is it possible to paint onto lime plaster?

 

[Penners]

is it possible to paint onto lime plaster?

Oh yes. Limewash, casein paints, distempers - they're all breathable and suitable to go over lime plaster.

http://www.buildingconservation.com/articles/lwdistempers/lwdistempers.htm

http://www.mikewye.co.uk/NewNaturalPaints.htm

 

[jungle_jim01]

thanks, those look really good...so i'm wondering now about the bathroom...(to be)....there's one external wall most of which is actually a chimney breast so not directly outside. presumably this could be plastered with modern materials and a waterproof paint applied....but i'd be interested to know if anyone's got a traditional solution?

 

[Penners]

one external wall most of which is actually a chimney breast so not directly outside. presumably this could be plastered with modern materials and a waterproof paint applied....but i'd be interested to know if anyone's got a traditional solution?

The wall is not strictly an external one, but presumably it's still founded in the ground? And open to the atmosphere at the top?

In general, and with a few questionable exceptions, any part of a period building will be happier if it is constructed with/coated with traditional, breathable materials. So received wisdom suggests that your bathroom wall should be treated in exactly the same way as any other - don't suffocate it with gypsum plaster and/or waterproof paint.

If your bathroom is very steamy and liable to condensation, the solution is good ventilation/extraction.