Building a chimney breast for a wood burning stove

[JennyC]

I'm looking to build a chimney breast in my lounge to take a wood burning stove, only a small one, around 4kw output maximum. Looking at the building regs regarding solid fuel appliances in AD J, I can't get my head around the closest point at which you can use combustible materials.

Basically, we have a masonry external chimney breast that we intend to run a liner down, but I want to construct an internal element projecting around 300-400mm from the lounge wall. Currently the wall is flush with the opening and the recess for the fire goes into the external chimney construction so there is no internal element and I want to add one to make a feature out of it.

Is it sufficient to build this new internal part from timber stud and line it with skimmed fireline or a cement based board, or will the heat cause warping/create a fire hazard? I will be lining the recess itself with some sort of limestone but am looking at 15mm thick tiles, not sure if they will be thick enough not to crack. I'm also considering building with lightweight blocks like Toplite GT1 straight off the concrete floor slab as it will only be imposing self load and this will avoid the need for any timber, but it seems a bit extreme and I wondering if properly lined studwork might be adequate?

Thanks in advance for any advice anyone can give.

 

[TheVictorian]

Someone will be along in a second highlighting all the regs, but I wouldn't even consider making it out of timber personally. Blockwork is easier to do and heat resistant.

 

[Norcon]

Anything is possible. Steel studding, vermiculite fireboard and plasterboard!

http://www.fahrenheitstoves.com/our-services-2/false-chimney-breasts/

 

[JennyC]

Thanks all,

In the end I went for only a 100mm projection for the chimney breast, so I built it out of lightweight concrete blocks off the floor slab and used some wall ties secured to the existing inner blockwork wall. It worked out cheaper materials wise than going for a frame and board method.

I also read up on using gypsum plaster around the recess for the fire and problems with it cracking/blowing where temperatures reached over 50 C. As I wanted a smooth, paintable finish to the recess then I opted for Everbuild heatproof screed and plaster. Haven't actually applied it yet but hoping it will do the job.