Cold draft from roof lanterns

[snowman99]

We have an flat roof extension with two lanterns and an external flue for a wood burner. It was only finished last year. I’ve noticed a cold draft from the lanterns and flue. The flue draft was solved by filling the cavity above the stove with rock wool (it’s a warm roof). However the draft from the lanterns is still there slightly.

I can’t tell if the draft is getting in via the lanterns - I can’t see any obvious gap. Or it is coming in vi the lead flashing around the flue and then moving through the roof and exiting into the room via the lanterns.

I could seal up the gap between the plasterboard and the lantern glass? And/or seal around the lead flashing but I don’t see people doing this. Any ideas? The problem goes away when the wood burner is on rather than the radiator but it’s a bit annoying.

[snowman99]

moles said:

The wood burner outlet pictured is just the lead cowl ain’t it over the upstand?, it’s got a longer pipe with a mesh type terminal I take it?.

There is definitely a pipe of some sort under the lead up stand-I remember when it was installed. I can’t expose that now though. The lead goes to an upside down cone then twin wall flue which goes up a few metres more out of the pictures.

Edited by snowman99 on Wednesday 26th February 19:19