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- 23 Sep 2015
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Hi all,
I am about to replace all the fascia on a single storey extension that has a warm flat roof installed and it will expose an unclosed cavity.
The extension walls are entirely built with Celcon blocks, 4" inside and 5" outside leaf, presumably this was for thermal reasons, as they are expensive and not particularly sturdy in all but compression.
Anyway, the cavity is not filled and is open at the top, so negating any thermal benefit of the outer Celcon skin. This doesn't seem right to me and I was wondering if the cavity shouldn't be closed somehow, anything to stop the flow of air and therefore the transfer of heat, but preferably a thermal sock of some type.
The extension is getting on for 20 years old now, so regs will have changed, but I fail to see the point of using expensive thermal blocks on the outside skin if the cavity is open to atmosphere.
The roof has recently been replaced, but the cavity has never been closed since build.
Am I missing something in my assumptions or am I missing a cavity closer?
Many thanks
I am about to replace all the fascia on a single storey extension that has a warm flat roof installed and it will expose an unclosed cavity.
The extension walls are entirely built with Celcon blocks, 4" inside and 5" outside leaf, presumably this was for thermal reasons, as they are expensive and not particularly sturdy in all but compression.
Anyway, the cavity is not filled and is open at the top, so negating any thermal benefit of the outer Celcon skin. This doesn't seem right to me and I was wondering if the cavity shouldn't be closed somehow, anything to stop the flow of air and therefore the transfer of heat, but preferably a thermal sock of some type.
The extension is getting on for 20 years old now, so regs will have changed, but I fail to see the point of using expensive thermal blocks on the outside skin if the cavity is open to atmosphere.
The roof has recently been replaced, but the cavity has never been closed since build.
Am I missing something in my assumptions or am I missing a cavity closer?
Many thanks