Blocking off chimney breast, how much Kingspan can I get away with?

[fix]

Hi all,

I'm removing a gas fire and blocking up a chimney breast, I'm thinking to use kingspan insulation board, and then a thin plasterboard on top?

I have some spare 60mm kingspan and wondered if I can double it up to make 120mm? I'm not sure if there needs to be certain amount of void in the space behind... I'm intending to cut into the kingspan/plasterboard and fit a vent grille.

Thanks!

 

[aveatry]

I would say just add a wooden frame to the inside and screw plasterboard to that. Don't think the kingspan will do much just there. The spare kingspan will do more work for you on top of your loft hatch if its not already insulated.

 

[fix]

I would say just add a wooden frame to the inside and screw plasterboard to that. Don't think the kingspan will do much just there. The spare kingspan will do more work for you on top of your loft hatch if its not already insulated.

Hi thanks for the reply, to be honest my view was that the opening is the single biggest source of heat loss in the room, along with the window, so why not use it

No loft hatch, it's a bungalow with a dormer extension, not much that can be done up there except open the ceilings up etc!