Insulation around cooker hood pipe

[Dougie212]

hi there

I’ve just fitted the pipe work for a new cooker hood.. where the pipe comes out the ceiling there is a draft. It’s not huge and I’m not overly concerned but with our house being a 1860s built mid terrace, it has its drafts... and one by one I’m trying to deal with them. Should I just live with it as once the hood chimney is on it’ll be even less of an issue or could I pop some fibreglass insulation into the hole just to maybe slow the draft down a bit? I’m just cautious of fire hazards etc with it being in the kitchen. Thanks as always. Doug.

 

[JohnD]

Where does it go after the ceiling?

Mine run straight out through cavity walls, and I pack the cavity with a sleeve of mineral wool before pushing the duct it, then I seal the ductto the wall inside and out. The mineral wool should bulge back to block draughts into or out of the ceiling void.

You can use mineral wool, it's not flam, and you can use pink expanding foam (fire foam) to seal the join, but only a bit in case you need to cut it out one day. You can use filler and redecorate over the foam, after cutting it flat.

If your duct exits through a roof, you need extra precautions to prevent rain penetration.

 

[Dougie212]

Thanks for your answer John... it goes into the ceiling and across to exit out of the wall.. I’ve packed the pipework as it goes out the house with insulation, I was just a little concerned about putting it into the hole in the ceiling over the cooker. I’ll avoid foam I think as like you say it may need to come out again.. but mineral wool should be ok?

 

[JohnD]

yes

You'd only need enough foam to fill the joint, in the same way that you might use silicone or caulk. It will prevent dirt or spiders falling down, as well as sealing draughts. If it's just a bead like that, you can cut through it with a serrated knife if you ever need to take the duct out. Being pink fire foam, it will swell up and prevent flame or smoke getting into the void if necessary. Mineral wool should do the job if packed tight.