How much to strip back damp stone wall

[sarahj]

We've lived in this house for eighteen months now, it was a seldom used holiday home for 25 years before that, and I am slowly uncovering all the horrors that we knew were there but didn't want to look at yet! Previous owner had done a grand camouflage job.

Have started to tackle one of the damp walls in the sitting room yesterday. The wall used to be an outside wall but now is an internal wall with cement plaster all over. concrete floors in both rooms, the sitting room floor is very old concrete and easily broken up. the plaster meets the concrete and this is where everything is very damp. On removing the blown vinyl an inch of plaster came away as well and the skirting oard turned into dust liberating many woodlice. This layer drops away to dust up to about my head height, the layer underneath about three feet up, but the layer under that is rock hard. Do I try and chip away this as well to uncover the stone or do I just leave this layer as it is.?

Would the stone wall also be wet up the inside? - sorry forgot to mention we are built into side of hill and water is travelling underneath continuously so we know we will never completely dry out.

My gut feeling is that we should expose the stone but how do you remove this iron hard layer without doing damage? So far I think we have nearly 3 inches thickness of plaster and none of it appears to be lime. Would lime plaster have hairs in it?

Sorry for the ramble but I'm terrified I've started something that I won't be able to do properly!

Sarah

 

[sarahj]

Me again, I forgot to ask - if the bottom layers ARE lime plaster and they aren't loose could I leave them there and would the wall still dry out, and could I then do a lime skim over the top?

Sarah

 

[Andrew Bodenham]

sarahj,
First of all, don't worry! Starting something like this for the first time may seem daunting, but nothing in house construction is rocket science and most things can be put to rights without too much trouble or expense.
Given that previous owners (possibly many pervious owners) have done some sort of botch-up your intervention will not make things any worse, and hopefully make it much better.

You need to go deeper into the wall to find out what the construction is, and to discover exactly what has been used. I'd be inclined to strip back a test area about a foot square near the base of the wall. A hammer and cold chisel should get through most things until you arrive at the base materials that the wall is constructed from.

If there is lime plaster under everything else it will probably not survive the removal of layers on top, so you'll probably be looking at complete removal back to the brick / stone.

Sounds very wet for an internal wall, so certainly open it all up to investigate the cause. Only then will you be able to work out a suitable remedy.

Good luck!

 

[MdB]

Sarah,

You might find my story interesting:
http://periodpropertyshop.co.uk/phpBB2/viewtopic.php?t=6885&start=0
http://periodpropertyshop.co.uk/phpBB2/viewtopic.php?t=6930&start=0
in that I had a similar problem. I'm now putting it all back together and it is looking far better than it originally was though I haven't fully stopped the damp yet as the floor is trapping too much moisture which is being forced up through the walls. Hopefully the improved drainage outside will help this over time.
This is what the other wall at the other end of the house (very similar problems) looks like now:
http://www.flickr.com/photos/pudontour/683781722/in/set-72157600584769701/

 

[chuckey]

My rock and rubble cottage has this feature as well ( minus the damp). What the extention bodgers did was to build the rear section up against the original house, so we have the benefit of a cavity wall(vented to the outside!) running right down the centre of the house. I would look very carefully into its construction, as the water might be penetratinng via the roof or the side walls and running along the cavity. This "rock hard" stuff is a rich cement mix designed to cover the damp, i.e. the damp has been there a long time.
I did not have a severe damp problem, just intermittent flooding! so I went for a french drain to try to get the water to flow around the house though a new sewer with gravel backfill running straight under the house helps as well.
Frank

 

[sarahj]

Thank you for your kind replies. There are at least three layers of inch thick plaster undercoat - you can see the keying in lines on each layer - but the weird thing is that the last layer next to the stone is the hardest one. It is almost impossible for me to make any indentation in it with hammer and chisel. the only way I was able to uncover an area of two inches was to do this right at the bottom of the wall where I could scrape away the concrete floor and work downwards.

If I can't remove the final layer can it stay, and how do I know what its made of?

Sarah

 

[Mark]

that layer is almost certainly strong concrete - and it needs to come off.

You can get an sds hammer drill with rotate stop (ie it will chisel) from £45. They will go through it.

With any luck you might find that once you get a small patch off and you can get under it, then things get much easier.

 

[Andrew Bodenham]

You could investigate a small area by drilling into it with a masonry drill. A grid of holes about 1" apart should perforate the material sufficiently to let you break it up with hammer and chisel.

Proceed with a little caution - who knows what may be in there!

 

[zunetunes]

I've got an external wall, similar. The original lime plaster had been removed and it had several layers of modern plaster on top of the same very strong (in places) concrete layer. It was hard to get off, but i realise now, essential. wall is drying out nicely now.

 

[Anne]

I agree with Mark get a little hammer breaker it's some sort of concrete and it needs to go.