Solid Stone Walls

[painterspal]

Hi,
Not sure if I've put this in the right thread.

Bit of background on the house.

We have an old stone farmhouse (traced it back to 1850, but it's older than that) walls 600mm thick - rubble stone (not good quality stone) which has been spar'd over in the 1960's. Interior walls - think they have been tanked with a slurry mix - the floor apparently was timber but replaced with concrete walls (2007 before we purchased it in 2009) tanked at that time. The house is built on solid rock (as we found out when building new extension - kango/pick axe job to parts, then parts which were over a meter of 'infill earth' down to find a solid base for footings.) When hacking off some of the spar to join in the new cavity of the Ex we found it 'killed' the old stone so hacking off the rest is a nogoer. Interior wall plastered and is the same situation - so again we are not able to hack it all off with out damaging the stone.

What we want to do...

We want to insulate the interior walls but there is some 'damp' to the walls, this is most probable caused by the spar getting hairline cracks - which we can't see but after 40 years must be there. Traffic in the lane has increased since pony and trap days to farm machinery taking up the full width of the lane...!! Weights have increased from a couple cwt to tons...! plus they now drive at 90miles an hour....!

We are going to re-render over the spar (your comments on this would also be appreciated) We are worried about causing more damp (is called intestial?) to the walls behind the insulation.

How would you go about it; the house is only one room wide so losing on the width is an issue, so keeping things to a minimum while getting the best u-value.

Any helpful comments/suggestions would be appreciated.

OHhh...... PS: My otherhalf was a builder now retired or is that just tired... !! while used to the 'old ways' is not up to speed with some of the 'new' technology.

 

[dann09]

1. What are you calling "spar" could you describe it a little more?

2. Insulating and rendering the exterior of stone and rubble filled walls is, typically, a best practice way to go. However, it's expensive and must be done by conscientious, experienced, plasterers.

3. Trouble is, with salt damaged interior plastering, no matter your remedial solutions, the salts will remain in the plaster and, depending on whats "done," will continue to transfer from the masonry.
Hacking off and rendering is the typical remedy. Although you might go the internal insulation and rendering, or even the re-tanking, route. Has the in-situ tanking failed?

4. If you can supply pics and an annotated floor plan ref. tanking and damp.

perhaps further advice might be given.Given your type of structure, there are no fool-proof solutions to any of the above, and after milking this forum for suggestions, perhaps call in an independent damp and timber surveyor for a written report with solutions.?

 

[pinenot]

The history of various works done over the years is a fair indication of trouble built in.
Solid stone wall building were built to "go" with the natural cycles, unfortunately (with all the right intentions) works to stop the movement of moisture have effectively damned this and as we all know that water has to go someplace.
Tanking floor and walls simply pushes it away, sometimes too where it's not wanted.
Your solid stone walls were built with lime mortar...don't use cement this impervious to moisture also...lime render also allows for free movement of moisture. This moisture, most noticeably from the exterior, rain and the like, will only penetrate 9" or so and dry out in the wind & sunshine (just like washing on a line) that's why the walls were built so thick.
Think of it like bending in the face of a wind, rather than trying to force against it, you'll do a lot better.
You could try water lancing to take the old render (spar?) off without damage, failing that clean off any flaked or unsound areas and re-render with a lime based render.
Internally there's an unfamiliar system called 'Hempcrete' which has wonderful insulation properties and moisture permeable (it will wick away internal moisture)

Go with the flow don't fight it