Can Lime save the day?

[Taff in Glaws]

I have a modernish constructed extension on back of my Viccy Terrace that consists of a mixture of blockwork, red brick and a concrete floor. The original outer wall of the main house that is a mixture of Cotswold stone and red brick has been rendered and plastered with cement and gypsum. It is clearly damp and exuding salt like deposits.

I recognise that the construction of the extension has not been sympathetic to the trad methods of the original heart of the house but the feasability and cost of replacing the floor and construction would be a sinful pyrrhic victory. There are no damp problems elsewhere in the extension and I wondered whether it is worth hacking this wall off and replacing with lime?

Perhaps it's a bit naive of me but I thought this wall could act like a snorkel so the property could breathe at the back! :?

 

[MdB]

If it is modern, does the wall have a cavity? If it does, and you have damp on the inside then there is a fault somewhere in the wall which should be found and fixed. If there is a cavity and you don't have damp on the inside then you can do what you like to the outside as it is for cosmetic reasons only.

If you don't have a cavity then lime render on the outside will help keep the wall dryer.

 

[Penners]

If it is modern, does the wall have a cavity?

Also, does it have a dpc? If so, could the rendering have bridged this?

 

[Taff in Glaws]

Sorry I probably wasn't clear enough. The wall in question is 1850 construction and is an external wall to which the extension has been added thus it now is one of the internal walls!

Not sure if that's clearer

 

[MdB]

If it is an internal wall, the question then is why is it damp? Is it rising damp? (if so how far up the wall is it going?), is it condensation? or is it coming from above somehow? As is it sounds like the current arrangement has been there some time, it looks like an on going problem so the moisture has to come from somewhere.

Major salting occurs when a damp wall is allowed to dry out (I posted a previous picture from my house somewhere here) which then stops when the wall has dried (min stopped after about 3 months and hasn't come back). Reoccurring salting suggest moisture getting into the wall from above or below and then evaporating out through the wall.

 

[Taff in Glaws]

Damp going no further than a metre up wall. I suppose it could still be drying out as was rendered with cement and gyp approx 2 months ago despite me suggesting lime may be more appropriate for this wall in keeping with the original construction. No moisture ingressing (?) from above, the cotswold stone wall extends to full height of 3 stories and down to the cellars that did flood last year forming the infamous indoor baths at Kingsholm

Perhaps I need to give more time to dry out?

Or just get on and hack the offending material off and replace with lime and stop pontificating?

 

[MdB]

Perhaps I need to give more time to dry out?

Yes.

Or just get on and hack the offending material off and replace with lime and stop pontificating?

I wouldn't bother. Once the wall is dry, where is the water going to come from that has to get out?

If it was your cellar then it would be worth considering but the damp isn't into climb all the way up from your cellar so where is it going to come from?

 

[Penners]

I agree with MdB. You should allow more drying time.

Dealing with damp is invariably a step-by-step thing. You try one thing, and if that doesn't work, move on to another, and so on. If the wall was rendered and plastered only a couple of months ago, then you can't yet rule out the possibility that this is a simple drying-out process.

However, your description of the damp rising about a metre up the wall is a bit of a hint that there might be a bit more than that going on.

Is there central heating in the room? If so, I should wait until you;ve had the heating going for a few weeks, and see what the situation looks like then. Remember to keep the room ventilated too.

 

[Taff in Glaws]

That's helpful. Thanks Penners and Mdb. Best I get that radiator in soon before the cold creeps in anyway.
Cheers