building a fireplace inside an Orangery

[richard at home]

i'm thinking about building a fireplace in our orangery and putting in a cast iron woodburner.

At the moment I have yet to lay the insulation or floor screed, so I am guessing that the base of the fireplace should be built up directly onto the slab?

I was also thinking of putting in a duct from the outside, under the fireplace with a vent directly in front so it can draw air in from outside without creating draughts across the room.

I know the woodburner only needs a flat base and non flammable back but I'd prefer to build a proper fireplace with a chimney breast.

The Orangery is quite big(7x4M) and will have wet underfloor heating, but we want the fire in there as a feature and we might get one with a back boiler to supplement the gas CH.

Any thoughts?

[richard at home]

Building regs means you have to have ventilation with a real fire, so it makes sense to have the vent as close as possible to the fire rather than sucking cold, outside air across the room.

The main issue I'm trying to work out is that will having the fireplace built on top of the floor slab rather than on the floor screed create a cold bridge. Technically it does, but no more than the interior walls do I guess...