briany
Member
- Messages
- 29
- Location
- Waterford, Ireland
Greetings, I've had a highly entertaining few weeks reviewing the reams of super advice on the discussion forum.
As someone just about to start a renovation project on an early 19century terraced miners cottage (in Southeast Ireland) I've been diligently educating myself as to the best way to renovate as sympathetically as possible.
I have a very specific question at this point, which I’ve not been able to answer through a trawl through the posts:
My cottage has been rendered externally with cement pebbledash, and the internal walls were cement and gypsum plastered - the upshot being the internal plaster is detaching itself from the wall
The obvious answer to this is to remove all the existing plaster down to the bare walls (24 inch stone and mortar) and lime plaster (instead of an air-gapped drylining - it’s just not right, even if it may be effective…). The external render will have to stay due to budgetary constraints at the moment.
My second priority is to introduce a decent measure of insulation to the interior side of the external walls. Going down the road of breathability, sheepswool insulation covered by lath and plaster was the choice I was going for, despite the expense (something like seven times the price of fiberglass by volume).
But I came across a reference to Unilit 20, which is a mix of lime plaster and perlite. This proprietary product claims to have a u-value of 0.066 w/m3, but the post said it was quite expensive (plus most likely not available in Ireland, where we’re about 20years behind the UK in period property preservation and planning. I could tell you horror stories).
My question is this: would it be effective to mix plain common-or-garden perlite, available from garden centres at a reasonably cheap price, with lime plaster and apply, say, a 6/7 cm layer between the scratch and finish coats to achieve a decent measure of breathable insulation at a very reasonable price? Will it retain breathability (I think so…), and structural strength (not sure…) and insulate well (not sure either…)?
Thanks, in advance, for your advice.
Brian
As someone just about to start a renovation project on an early 19century terraced miners cottage (in Southeast Ireland) I've been diligently educating myself as to the best way to renovate as sympathetically as possible.
I have a very specific question at this point, which I’ve not been able to answer through a trawl through the posts:
My cottage has been rendered externally with cement pebbledash, and the internal walls were cement and gypsum plastered - the upshot being the internal plaster is detaching itself from the wall
The obvious answer to this is to remove all the existing plaster down to the bare walls (24 inch stone and mortar) and lime plaster (instead of an air-gapped drylining - it’s just not right, even if it may be effective…). The external render will have to stay due to budgetary constraints at the moment.
My second priority is to introduce a decent measure of insulation to the interior side of the external walls. Going down the road of breathability, sheepswool insulation covered by lath and plaster was the choice I was going for, despite the expense (something like seven times the price of fiberglass by volume).
But I came across a reference to Unilit 20, which is a mix of lime plaster and perlite. This proprietary product claims to have a u-value of 0.066 w/m3, but the post said it was quite expensive (plus most likely not available in Ireland, where we’re about 20years behind the UK in period property preservation and planning. I could tell you horror stories).
My question is this: would it be effective to mix plain common-or-garden perlite, available from garden centres at a reasonably cheap price, with lime plaster and apply, say, a 6/7 cm layer between the scratch and finish coats to achieve a decent measure of breathable insulation at a very reasonable price? Will it retain breathability (I think so…), and structural strength (not sure…) and insulate well (not sure either…)?
Thanks, in advance, for your advice.
Brian