Kitchen venting cooker/hob

[Patters1978]

Hi all question need help on please

Part of our kitchen ceiling has above it a pitched roof with a loft hatch and standard insulation.
It's cold because it also has vented roof tiles on the outside.
My plan this weekend is to pull the ceiling down and rigid insulated over the roof joists ( using a battery to allow an air gap between joists ) then either vault the plasterboard ceiling or keep it flat unsure on this part currently.

My question tho is just below we plan to have an electric hob does this hob have to have a hood and if so how can I vent it without a draft coming back down it?

 

[noseall]

Part of our kitchen ceiling has above it a pitched roof with a loft hatch and standard insulation.
It's cold because it also has vented roof tiles on the outside.
My plan this weekend is to pull the ceiling down and rigid insulated over the roof joists ( using a battery to allow an air gap between joists ) then either vault the plasterboard ceiling or keep it flat unsure on this part currently.

Eh?
'vault the plasterboard'....? Is it your intention to remove the ceiling joists?

My question tho is just below we plan to have an electric hob does this hob have to have a hood and if so how can I vent it without a draft coming back down it?

Cooker hoods are usually one way streets. I think it's down to how the air is filtered.

You don't necessarily need an extractor directly over the hob, although this is the most efficient/adventitious position for a kitchen extractor. If the extractor is fitted elsewhere in the kitchen, it needs to be stronger (litres per second) rating.

 

[Patters1978]

Eh?
'vault the plasterboard'....? Is it your intention to remove the ceiling joists?

Yeah the beams that currently support the flat ceiling I believe are not structural but until I take the full ceiling down and do a load calculator I won't know. It's a small roof 2.5x1.5m space up there is tight so can't really measure correctly.

So the hood shouldn't let anything back through is it done by just a flap inside then?

 

[noseall]

Yeah the beams that currently support the flat ceiling I believe are not structural but until I take the full ceiling down and do a load calculator I won't know. It's a small roof 2.5x1.5m space up there is tight so can't really measure correctly.

Lean-to roof?

So the hood shouldn't let anything back through is it done by just a flap inside then?

I've never heard of any issues with a cooker hood, no.

 

[Patters1978]

Lean-to roof?

Yeah lean-to

Main roof beams gotta be like 2.5m max has a massive perlin in middle of it also.
So don't think the ceiling joists are supporting anything but the ceiling.
TBF until it's taken down I won't know if it will look stupid being part vaulted anyway it's kinda pointless imo but the wife likes the idea

 

[Harry Bloomfield]

So the hood shouldn't let anything back through is it done by just a flap inside then?

The usual way, I to have a one way, gravity closed, flap vent, on the end of the exit pipe, to prevent drafts. The fan running opens the vent, when it stops, the flap closes, preventing wind blown air entering.

This sort of idea... https://plasticsuppliesdirect.co.uk...-gravity-shutter-vent-outlet-brown-125mm.html