We need to put in a chimney liner for a rayburn and one for a woodburner, we are thinking of using the flexible liner but not sure what size we would need...any advice would be very welcome and any other considerations which may be useful to know.
Thanks!
I think the sizes required will be specified within the installation instructions for the Rayburn and wood burner.
Might be an easier read than the building regs document (no offence MdB!).
The whole installation must be compliant, which includes things like the liner, the fireplace dimensions etc. It must also be certified by a competent person. This can be the council building control officer (fee payable) or a HETAS qualified installer (fees included). You can DIY and get the BCO to certify or just let a HETAS installer do everything.
If you're buying the Rayburn and/or wood burner new then the dealer will almost certainly be able to recommend a HETAS installer. Costs will vary, of course, depending on how you decide to proceed.