Advice: Flat roof penetration Extractor flue/terminal outlet

[DemiDon]

I have to put the flue from my cooker hood through a flat roof (warm) am I right in thinking it is a relatively simple job of cutting the correct sized hole through the roof, putting a weather proof collar over the flue (with its rain cap) with the collar going under the felt/roof covering? And not to mention making sure it doesn't leak with judicial use of cold bitumen.

Whilst I'm confident enough to do the job - I just have this little feeling I'm missing something.

 

[noseall]

You need to buy a 90 degree lead slate. Cut a 120mm hole through the deck and insulation. This hole can be weathered using the lead slate but it will need professionally bonding to the roof material.

You can then pass a piece of 110mm plastic drain pipe through the hole forming a duct. This can be siliconed into place by pumping silicon around the pipe as it sits in the lead slate. You may need to secure the pipe until the silicone has cured.

The top of the duct can be finished with a plastic rain cowl.

The extractor can be connected to the duct via flexi hose.

 

[DemiDon]

Thanks Noseall
When you say that the lead slate must be professionally bonded to the roof material' how is that actually done?

 

[noseall]

Not bodged!

If it isn't done well then it will fail. I would employ a flat roofer to hot-pot the slate down.

 

[Nige F]

You can get good hot pot @ the Rovers Return, so I`m told Maybe a better idea would be to look at www.liquidplastics.co.uk The stuff was used on my son`s roof recently , by a roofer M8 of his ...I am impressed. Let us know how you get on.