Newbie - all advice welcome :)

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Triggaaar

New Member
Dec 17, 2019
2
UK
Hi all

I'm new and have been enjoying reading some of the many threads here.

I'm currently building a kitchen extension for our old home in the UK, and we're planning to install a wood stove.

The main house is 100 years old, and while we've added what insulation we can, it's not great. The new extension will be well insulated. It will have underfloor heating, provided by a mains gas boiler (which also provides heating for the rest of the house, via hot water radiators).

We'd like a log burner because we enjoy a real fire, and we can steal softwood from our parents (who have fallen trees in their garden). It would be useful to save on some heating bills (although I wouldn't expect to recoup the cost of the stove), and perhaps leave the inner door open to allow heat to go to the rest of the house. Our current choice of stove is the Jotul F373. It's cast iron, and contemporary, which will match the style of the room. It uses a 6" flue.

The room will be 31' x 24.5', with 9' ceilings. The roof will be flat, and as it's all new there's no existing chimney, so we'll be installing a straight flue from stove through the roof. I believe the regulations here (code) mean that the flue needs to be at least 15 feet long, on top of the stove. About half of that will be above the finished roof. I plan to provide a direct air feed to the stove.

The floor and wall around the stove are non-combustible.

I think we'll need a twin flue through the ceiling/roof and above. I don't know if it's best to also have a twin flue below the ceiling, or best to have a single skin, and allow some of the heat from the flue to transfer to the room before it's gone. I think keeping the flue gases hotter helps with a better draw, but since our flue will be completely straight with no bends at all, and relatively short, perhaps letting the gases cool a little (and warn the room) is not a bad idea? Although I have no experience with stoves, I'd like to install it myself (I'm doing the build myself, with some help, and a roofing company would make it weather proof while fitting the roof covering).

Any tips much appreciated :)
 
Welcome. Stove pipe connects the stove to the chimney pipe at the ceiling. Chimney pipe must be used at the exit from the room. Typically a ceiling support box is installed that handles this transition while maintaining proper clearances. If the chimney pipe goes up through an attic space it will need an insulation guard. At least that is what is required in the US.

What is the wall construction behind the stove? Is it solid masonry or masonry over wood studs?
 
Thank you :)

Stove pipe connects the stove to the chimney pipe at the ceiling. Chimney pipe must be used at the exit from the room.
Thanks. Stove pipe appears to be single skin. I assume the chimney pipe is the twin wall insulated flue pipe. That needs to be used from just below the ceiling (can't remember the measurement, but it's in the regulations).

Typically a ceiling support box is installed that handles this transition while maintaining proper clearances. If the chimney pipe goes up through an attic space it will need an insulation guard. At least that is what is required in the US.
No attic space, just a flat warm roof. I don't know anything about ceiling support boxes :)

What is the wall construction behind the stove? Is it solid masonry or masonry over wood studs?
The wall is made from blocks. Where we don't put the fire, will also have 1 inch of insulation inside the blockwork (as well as 6" of insulation in the cavity), and then plasterboard, and a skim of plaster. But where we put the fire we won't add the 1 inch of insulation, and instead of plasterboard we'll use a board that's more heat resistant. We'll probably then plaster that, but we could tile it instead.