Backing for wood burning stove

[Mark2bikes]

Hi,
Just putting in a wood burning stove in a timber home. All the info we have found so far (eg planningportal.gov.uk) states that the stove must be either 30 cm from the wall OR that there must be a 75mm layer of non combustable surface on the wall behind OR 150mm if the hearth does not touch the wall. Stangely, it the hearth is 150mm from the wall then there appears to be no requirement to fireproof the wall behind!!
Most of the backing board available seems to be 6 - 12 mm not 75mm. What can be used that is 75mm thick and doesn't weigh a tonne?

Also - is there any advantage to using a section of single skinned flue inside the room and then adapting to double skined where it goes through the ceiling and roof space (bungalow) ? I thought perhaps this would get more KW out of the fire rather than letting it up the flue?

Thanks for any advice,

CHeers,
Mark

 

[Mark2bikes]

OK, so no help yet, but further reading has revealed that you can in fact use something less than 75mm as long as it has the same rating - anything to recommend on top of 12mm pasterboard wich is itself ontop of 12 mm ply?
Thanks