Stone house with damp

[babs]

HI - Im new here so this is a a starting point for help with an old cottage we recently moved into. It was revevated in 1988 but the outside has been covered in cement/pebbledash. There has been a drimaster installed inside and it keeps condensatino down. However, we have just taken the bathroom tiles of and discovered a very wet patch on an outside wall. The plaster has been down right down to the ground. There seemed to be a leak coming from the toilet pipe, but so far we havent found it. A builder locally suggests removing the plaster, covering the wall with something called (synatproof - cldnt spell it!) which looks like a tar substance! Then cementing the wall and tiling! Any help much appreciated. If it is any help we live in Northern Ireland. And...I would really like to communicate with someone who has done work to a house. (on a small budget!) Thanks

 

[Gervase]

Your best bet is to use the search facility to look for 'damp' and 'stone' - it's an issue which crops up on a weekly basis.
But, in brief, modern coatings don't work; they'll make the problem worse in the long term and may even damage the fabric of the building.
Sadly old houses don't react kindly to short cuts, so the ideal solution involves...
1) addressing the source of the moisture - which means fixing any leaks, making sure ground level outside is below floor level inside and ensuring your gutters are working and not overflowing.
2) letting the fabric breathe - which means removing the cement and pebble-dash (which looks horrible anyway) and replacing with a lime render and a breathable surface treatment like limewash or a clay pain.

 

[babs]

Thanks for the advice. Inside is definetly higher than out. We had a full survey done when we bought and the surveyor was 100% certain that we dont have rising damp. But the builder thought we had! :? Personally i dont think so - there is no smell and there is no sign on the outside of the building. There is a damp proof (electo) system installed - again in 88, so we may have to look at replacing that (if that is suitable) I would like to work with the house as we intend to stay here for a while.
Again - thanks for now - Im sure ill be back again very soon

 

[babs]

Sorry - just forgot to say - there is salt deposits on the inside of the bathroom wall , some higher up than others. Any recomendations for the treatment of this?

 

[Gervase]

Sadly builders will often diagnose what makes easy work for them (says the builder :lol: ).
Rising damp is very rare, but so, too, is a modern 'damp proofing system' that works, and that includes the electro-osmotic systems.
I know it sounds prosaic, but the best way to solve damp is to let the house work as it was originally built!
The salt efflorescence on the walls isn't easily solved until the underlying plaster/stone is allowed to dry and breathe (sorry, I know I sound as though the needle's stuck, but it really is the best tack to take!).

 

[Matt Green]

Sorry - just forgot to say - there is salt deposits on the inside of the bathroom wall , some higher up than others. Any recomendations for the treatment of this?

Gervase has pretty much got this covered, but as an aside:

The salts are there because they have moved from the wall to the surface of the plaster. The are soluble and move in water. Either the water is coming up from the ground (with more dilute salts in), or from a leak, or being absorbed from the internal environment, due to other, hygroscopic, salts within the wall.

Ground levels should be 6" below floor height and breathable finishes will sort the situation out in the long term once the water source has been dealt with.


Matt.

 

[Penners]

Babs - just so you know, Matt and Gervase between them are really good guys to give you the best advice one this. They're both experts.

 

[babs]

Cheers guys - all help and advice will be taken on board. I wonder though - will the concrete floor be a major problem coz i really dont want to shift it as it covers the whole blooming house!

And...if i get the bathroom dried out, use a lime plaster on the walls - how can i water proof it? Can i tile over without any implications?

By the way - with the tiles off the wall looks like its drying out already - and still have not found a leak - but still 3 walls to go!

Again - thanks

 

[Gervase]

Concrete floor shouldn't be a problem - PROVIDED the exterior ground levels are at least six inches lower than slab level, and all external pointing/render is done with lime rather than cement.
As for the bathroom, if you want to tile it, I'd recommend drylining using green plasterboard (the water-resistant stuff), tanking that with the BAL system and then tiling. You're then guaranteed a perfectly plumb and square surface for tiling, a breathable wall behind and a waterproof barrier in between.
Also, if you're fitting a shower where the cubicle tolerances are usually only 12mm or so, drylining a stone wall is often the only way to ensure that, as stone walls usually have a batter (or 'lean') in excess of that twixt floor and ceiling.

 

[Penners]

if you want to tile it, I'd recommend drylining using green plasterboard (the water-resistant stuff), tanking that with the BAL system and then tiling. You're then guaranteed a perfectly plumb and square surface...

...albeit bloody expensive! The BAL kit alone is about 65 quid.

 

[Gervase]

Aye, but you get enough to pretty well tank a room, provided you buy a bit more polyester fabric. And it does work - which is more than you can say for a lot of things that'll cost more than £65!

 

[shelli]

Yeah, like everything we've ever bought from Focus DIY shed

electric Chainsaw, Angle grinder, strimmer etc etc -

Is is just us or does anyone else have to take back 50% of the things they buy due to poor manufacture and said things being unfit for purpose?

It's a real b***ache - especially when it's 20 mile round trip to return it!

 

[Gervase]

Shed stuff is often awful so it's usually a false economy. Once you've used decent quality stuff (Makita or De Walt) you really notice the difference. That said, some B&Q own brand stuff is serviceable in a rough, ready and so-absurdly-cheap-that-if-you-break-it-you-don't-cry fashion that it's tempting. I use their £35 nine-inch angle grinders for heavy duty stone cutting (saving the £130 Makita one for slate and metal - which means it's outlasted three B&Q jobs). They also do a 1050 watt rotary-hammer drill for the same price, which is ideal for light demolition work or whizzing up a bucket of top-coat plaster

 

[shelli]

and there was me about to plug in the hand blender for that job!!

 

[Gervase]

Bet your Victoria sponges are a knockout! :shock:

 

[babs]

Well!! Cooking sponges with rotary hammer drills??? Now theres a thought!

Ok - ive had a hard day! Anyhow - back to the grind stone........all help much appreciated and if spending £65 quid on 'something' to line my walls means i can tile afterwards it will be well spent! U try telling a 13, 16 and 19 year old not to wet the walls when having a shower!

Now the hard question? Where do i get green plaster boards and the BAL stuff? Beginner here remember!

 

[Gervase]

Any good builders' merchant will sell them - Jewson's and Travis Perkins certainly do.

 

[babs]

ahem?? Jewsons? Travis Perkins?? Wots that? Foriegn language? I live in Northern Ireland!

 

[Gervase]

Ah, pologies. Then I suppose you'll have to choose between green or orange plasterboard :twisted: It really should be the green, though!
Seriously, just march into any builder's merchant and ask for water-resistant PB for bathrooms or Gproc MR and the BAL tanking system. If they're any good at all the'll know exactly what you mean.

 

[babs]

lol Very good!!
Seeing as i 'sit on the shelf' any colour will do for me! but i shall take your advice and march straight into the nearest building merchants yard with a prinout of your advice! Havent got much done since the other nite though so hopefully with the bank hols wkend ill get moving and get the place dryed out. Do we have to wait till the wall is solid dry? and how long approx will that take?? (Its the bottom corner of one wall - bout 2 mtrs square)