Behind the kitchen rayburn is a one inch gap then a double brick wall (no cavity).
I'm swapping it for a newer one, so now is the time to insulate behind it.
3 inches of kingspan then plasterboard is one idea.But then I wuuld lose 4inches of kitchen.
any better ideas?
(As its only 2 square yards price doesnt matter.)
[g]My Rayburn installer cautioned me about insulation in close contact with the back - reckons it can get significantly hot at times.
I've had mine stood out well from the wall, so that there is a substantial bit of studwork faced with cement board and the kingspan some distance back.
If I didn't have the space to do this, I'd probably use rockwool rather than kingspan.
Actually a couple of layers of Masterboard are probably better than nothing.
I wouldn't put polyisocyanurate close to a fire-based heat source. Although most polyisocyanurate board has fire retardants added, it still burns and gives off extremely nasty toxins when exposed to flames, even when it has enough fire retardant to prevent it self- sustaining a flame.
Indeed. We tried to burn scarp on a fire when building this house. Nasty clouds of black smoke., never caught fire, but I wouldn't want to breath it.
Its a case for asbestos really innit?
Fibreglass or rockwool must be the ones to go for, behind PB
NT
polyisocyanurate? in kingspan?
Sounds more dangerous than asbestos. [g]
The Natural Philos>> >>> Behind the kitchen rayburn is a one inch gap
Yup - kingspan is polyisocyanurate between two layers of foil. Try putting a match to a little scrap.
Check with the narrowboat & boat people. They routinely have wood burners and insulation.
The bare metal burners radiate intense heat. I think they use refractory tiles + firecement grout + fireboard/ masterboard + insulation. They can not use normal ceramic + plywood + insulation; the plywood turns to charcoal.
Would a facing wall of insulating blocks be sufficient? Fire retardant paint to cover it.
Dave.
For 2 sq yards I wouldn't bother.
But as heatloss is proportional to temperature difference and the back of the rayburn may get quite hot there could be quite a bit of heat loss through the walls, worth doing something I think (as well as increasing the air gap) [g]
In article , george (dicegeorge) writes
Out of curiosity I did a few calcs:
Assuming zero degrees outside and a wall surface temp behind the rayburn of 60degC then you lose 240W for a 2m area on the single brick (9") wall you described.
Just an inch of celotex on that would drop the loss to 75W (2" gives
45W).By comparison, if your kitchen wall is 3m high by 4m wide then the 10m not behind the rayburn loses 400W (zero outside, 20deg inside).
Total current loss 640W vs total loss for 1" behind rayburn 475W so it's still going to be a pretty lossy wall.
If you stuck 1" of celotex to the whole wall then stuck on some plasterboard then the loss for the whole would be 200W which sounds a bit better.
If you do just decide to go for insulating behind the rayburn, I would hack the plaster off the wall immediately behind (which is probably 1" thick) then infill with 1" celotex with a sheet of masterboard over the top with a good overlap for protection.
How does that sound?
thanks everybody for advice and for discussion- the bit behind the rayburn is the hardest to insulate so i'm concentrating on that, the rest of the walls and windows could do with some too (and when i repair the ceiling the major heatloss through the floorboards will be cut).
However its just occured to me that maybe I could put k> In article , george (dicegeorge)
except the wall will act as a heatsink down through the foundations and up into any more wall above it?
I'd concentrate on the inside.
cheers JimK (PS note bottom post)
I agree about not bothering to insulate the outside. I still think the idea of internal insulating block wall is worth looking at. Alternatively, if space is such an issue why not make a small wall built with side on bricks. Leave a centimetre air gap so that it projects about 75mm from the existing wall. Those bricks will will then become the thermal store. Surely someone can work out the resulting heat loss.
dave
But if a yard length of wall is 10 feet high and 1 foot wide then the heatloss through the side will be 10 times that through the bottom or top, but halve that because the inside wont be as cold as the outside, plus the ground is warmer than the outdoors, plus wind and rain on the wall cool it even more, thus it is worth insulating outside of the wall if I am ever to re-render it etc [g]
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