repointing a stone walled house

emmemm

I have this 100yr old house with the exterior plaster in bad nick.Some areas it seems to have come away from the stones.
Would it be acceptable (dampwise) to remove the old cement/lime render and just point between the stnes without applying any coats of plaster?
Should I use lime in the pointing mix?
Does the interior need insulating.The walls are eighteen inches wide.

Victor

Originally posted by emmemm
I have this 100yr old house with the exterior plaster in bad nick.Some areas it seems to have come away from the stones.

This is common, damp gets through the plaster and gradually breaks down the bond with the brick / stone over the years. The original design of these house was not to have exposed stone - they had plaster / and or paint. Exposed stone (unless it was finished stone like Leinster House, etc.) was usually only used for boundary walls and outhouses. If your house is 100 years old check with your local council if it is listed for preservation. Is suspect you might need planning permission to changed from plaster / painted to stone anyway.

Originally posted by emmemm
Would it be acceptable (dampwise) to remove the old cement/lime render and just point between the stones without applying any coats of plaster?

You could, but I suspect this will reduce the damp-proofing. While 18 inches is a good thickness, water / vapour could still get through.

Originally posted by emmemm
Should I use lime in the pointing mix?

You can either use a weak cement / sand mix or a cement / lime / sand mix.

Originally posted by emmemm
Does the interior need insulating.The walls are eighteen inches wide.

Probably, solid stone is a good conductor (i.e. poor insualtor) of heat. depnding on the condition of the interior of the walls, Gypsum do various stick on insulating / plasterboard slabs or you could dryline the wall if it is too rough. Make sure a vapour barrier is included. You will loose a small amount of floor space in doing this, but is much more energy efficient than putting the insulation outside (because you would need to heat up the walls when heating the house).

If messing around with the plasterwork. You might also consider investigating for rising damp and installing a chemical DPC and get the windows checked out.

emmemm

Thanks Victor.How about applying water seal to the pointing?

Victor

Originally posted by emmemm
Thanks Victor.How about applying water seal to the pointing?

If you are removing the plaster and just doing pointing using a chemical sealant might be a good idea, but I would use it on the whole wall (this is what they do when then clean historical buildings, it reduces soot / dirt build up, reduces water / chemical pentration and makes future cleaning easier).

Question: is there a risk of graffiti? "Nice clean" stone may present something more attractive to scribble on than manky old plaster.

Oh, if you are going to replaster, hack away any loose plaster, but there is little need to remove solid plaster - just score it to get a good key for the new finish coat.

emmemm

I suppose I would save myself a whole lot of work going the chemical route .Does this need to be applied every two or three years or so.No danger of graffiti in the wilds of Donegal.

Victor

Originally posted by emmemm
Does this need to be applied every two or three years or so.

I think the manufacturers say 10 years, but it would depend on conditions. The buildings in College Green (Bank of Ireland, Trinity College) in Dublin take a huge battering from pollution. I imagine your problem would be driving rain and a lot of it.

dalto23401

Victor wrote:

I think the manufacturers say 10 years, but it would depend on conditions. The buildings in College Green (Bank of Ireland, Trinity College) in Dublin take a huge battering from pollution. I imagine your problem would be driving rain and a lot of it.

Victor would you know what mix to use when skimming internal walls with a lime based plaster. I have tried with lime putty and sand and have ended up with alot of cracking.

Stoner

Victor wrote:

I think the manufacturers say 10 years,
.

Yeah I've used it before and it was a 10 to 20 year cycle, there are at least two types, the one that changes the actual chemical structure of the brick is the best (my brother used to work for a company that developed/made the stuff)