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Insulation - old stone walls


Looking for a bit of advice. We are in the middle of a complete renovation project on a 100+++ year old house in Ireland. We have completely stripped it down to nothing but the bare walls which are 2 foot thick stone/rubble and muck.

Trying to find the best way of insulating now. Our last house was around the same age - with similar walls and had been renovated in the 80's. It had practically no insulation. It was cold, damp and hard to heat.

We want to do it right this time and need to save on energy costs. external wall insulation has been the major confusion so far and we are fast approaching the time to start installing it.

We have narrowed our options down to three possibilities and would be very grateful if you could let us know what you think or have any other ideas.

1. Good ole Kingspan - battening out the walls and sticking kingspan to them. plastering over. Drilling a few air holes in various places on external wall to allow air flow behind insulation.

2. The Isover Optima system - had a architect recommend this. The product says that it is fully breathable etc. which sounds the right job for our old walls but if you check out the video below you will see that the insulation is pressed right up against the wall. I'm not sure how great an idea this would be on the old damp stone that we have. Also, cannot find much information about using this product for this type of wall. I understand that it is used a lot in Europe, maybe not so much in the UK or Ireland.

3. Sheeps wool - We were going to make up the battened walls on the floor, put a vapour control layer on the back side of the battens and then fix the battened walled panels into position - leaving a gap between them and the wall for airflow. Then pop 100mm sheeps wool insulation between battens - possibly another vapour layer - (possibly smaller counter battens to run electrics) then plaster board.

External wall insulation is out of the question as no overhang, walls need to 'breathe' and house has pointed stone walls.

If anyone could give some advice on the situation that would be great.

Many thanks



Re: Insulation - old stone walls

Not too long ago, there was an episode on TOH where they insulated a basement wall using a rigid foam board that had built in structural components (plastic) and vent grooves on the backside. It would be ideal for your application except that I cannot find the episode nor does the search engine help.

Re: Insulation - old stone walls

This is a different episode than the one I was looking for but it might help


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