Insulation materials behind stove

[Frod cortina]

Hello, We have insulated the whole of our 1940 house from the inside using rigid fibreglass bats and plasterboard. Its previous insulation value was very poor in solid brick. We are on the last room which has a large stone fireplace with a wood-burning stove in it, on an external wall. We use this in winter but not everyday.  I do not want this to be a cold spot when not in use and a huge heat loss when it is in use. I have about 4 to 6 inches to play with and still maintain a good air gap behind the stove but I am not sure what materials to use for both maximum efficiency and fire safety. What suggestions do members have for this scenario?

I should add that it has a flue pipe through to the top of the chimney with a proper watertight top plate and an insulated one at the bottom.

Advice would be most appreciated

 

[nod]

Your limited for insulation 

You shouldn’t even put plasterboard in there 

Most just add a couple of coats of render or cement board and tiles 

[Temp]

See Diagram 19 in Approved Document J.

https://www.gov.uk/government/publications/combustion-appliances-and-fuel-storage-systems-approved-document-j

 

That appears to require a separation distance of 1.5 pipe diameters between the flue pipe and combustible materials and a non combustible shield and air gap. Think this rules out using EPS or PIR in your case so will need to look at non-combustible insulation like Rockwool behind a fire proof board of some sort.

 

 

[jfb]

There are various different types of insulated render you can get - not sure how fire resistant they all are though.

Tends to be quite expensive for the U value it gives but there might be something appropriate.

 

Something like this (never used or heard of it before but seems to do well on fire resistance):

https://proofshield.co.uk/products/internal-external-wall-insulating-plaster/

[A_L]

3 hours ago, Frod cortina said:

I am not sure what materials to use for both maximum efficiency and fire safety

 

Foamglas is totally incombustible with a reasonably low conductivity, (about 0.04W/m.K).

 

https://www.foamglas.com/en-gb/applications-and-solutions/interior/wall/tiles/b-i-wall-render-tiles

 

A possible alternative if available is Diathonite Evolution render (0.037W/m.K)

 

https://www.diasen.com/sp/en/p/diathonite-evolution.3sp

[dpmiller]

two birds, one stone, perhaps?

 

https://www.firepowerheating.co.uk/thermalux-sheets?adwordspermission=1