Cooling a flue

[ellisgm]

Hi,

I had a gas fire installed last year, and the precast flue is getting too warm, causing the plaster attached to the flue to crack.

Without replacing the fire, are there any options? Like using heatproof screed (although I've only got about 3mm depth in the plaster) instead of plaster; replacing the raised ridge tile with a well vented cowl; or replacing the effected plaster with lime plaster?

Thanks.

[ellisgm]

Found another couple of options for improving the draw of the flue...

- Instead of replacing the existing ridge tile, add another cowl to the flue.

- Our house has no air vents in the external walls (upstairs or downstairs). There may not be enough air in the house for a good draw of air to send up the flue.

Or are these rant> Hi,

[Owain]

I don't think the draw of the flue is the issue - and it *should* have been checked by the installer, as *should* the ventilation.

If you have doubts about the ventilation being adequate I would urge you to cease using the fire until it has been checked by a competent gas engineer. (Not all CORGIs are necessarily as competent as they should be.)

Owain

[meow2222]

Maybe if you fit PB using high temp 300C silicone, the gap behind (and a gap top and bottom) will permit some cooling, the silicone will allow things to move slightly without cracking apart and it may all work.

Whats really needed - apart from fixing the problem - is a plaster with close thermal coefficient of expansion to the bricks/blocks. In principle you coudl try coating a block with patches of all the different plaster types and putting it in the oven, but I'm not especially optimistic about that one. Gypsum, lime, lime and chalk, cement and sand, cement and lime, mud/clay, and I dont know whats in the brand name preparations like artex, parrotskim etc.

Or if the crackings not too bad, mix thick hair into the plaster to hold it together when it cracks, and put lining paper to cover any future cracks.

Anything except fix the problem :)

NT