External Ducting from Cooker Hood Through Supporting Wall

[passmo]

Hi, I'm looking for some advice on some planned work.

We are planning to locate a cooker hood (typical stainless chimney type) on the wall of the kitchen above an existing hob. Rather than recirculate, I want to duct externally. The wall is a cavity wall, with brick outer skin and blockwork internal skin (concrete / breeze block type).

However, the wall with the hob is supporting the joists for the floor upstairs (semi-detatched house). The extract has a 6" duct, and has an adapter for 5".

Routing the duct at 90° to the other wall isn't an option, as there is a boiler there.

The ceiling has had new plasterboard fitted, but is not plastered yet, so could be taken down quite easily.

How would you proceed? I see a couple of options:

1. Core drill 5" for round ducting straight out.
2. Cut out and install small lintel and core drill below lintel, up to 6". Either resting joist on lintel or below joist.
3. Use adapter and go through wall with square / rectangular ducting.

I'll either do this myself or get someone in.

Thanks!

 

[kbdiy]

Option 1.

 

[passmo]

Option 1.

HI, Thanks, why do you prefer option 1 over 2?

 

[WabbitPoo]

Because a lintel isnt necessary

 

[passmo]

Because a lintel isnt necessary

Okay, that makes things easy.

Is there any min distance from the joist required?

 

[kbdiy]

Take a look at the outside of any number of houses - you will see all manner of large holes for flues, vents, soil pipes etc etc. Hence no need for a lintel.