Tue, 19 May 2026 15:48:33 +0100 https://www.greenbuildingforum.co.uk/newforum/ Lussumo Vanilla 1.0.3 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18399&Focus=310098#Comment_310098 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18399&Focus=310098#Comment_310098 Sat, 24 Jan 2026 16:41:33 +0000 gravelld
Tescon Vana works up to 90C, but that would be no good for the flue, certainly.

What have people used?]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18399&Focus=310099#Comment_310099 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18399&Focus=310099#Comment_310099 Sat, 24 Jan 2026 20:51:56 +0000 Dominic Cooney https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18399&Focus=310104#Comment_310104 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18399&Focus=310104#Comment_310104 Sun, 25 Jan 2026 09:59:18 +0000 gravelld https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18399&Focus=310107#Comment_310107 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18399&Focus=310107#Comment_310107 Sun, 25 Jan 2026 13:49:57 +0000 GreenPaddy
For the flue, is it a twinwalled flue? If twinwalled, then 90oC is likely fine, as it shouldn't be getting that hot. If it's black vitreous then of course much hotter, so high temp silicone. It may not make a perfect air tight seal over time, as you suggest, with a hairline gap at the mating surfaces, but compared to the leakage paths through your stove, up the internal of the flue, is it something to be concerned about?]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18399&Focus=310108#Comment_310108 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18399&Focus=310108#Comment_310108 Sun, 25 Jan 2026 13:51:59 +0000 Peter_in_Hungary
FYI high temp silicon sealant I have used had a rated temp of 1500 C and for my usage didn't crack or shrink, but then it got nowhere near 1500 C, maybe 300 C. Proper cleaning of the surfaces are v. important to get a good seal.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18399&Focus=310112#Comment_310112 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18399&Focus=310112#Comment_310112 Mon, 26 Jan 2026 19:11:08 +0000 gravelld
Could I use a high temp primer to stick the sealant to?]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18399&Focus=310114#Comment_310114 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18399&Focus=310114#Comment_310114 Tue, 27 Jan 2026 10:25:01 +0000 Peter_in_Hungary
If you have a top to bottom flue (i.e. a lined chimney with the space between the flue (liner) and the chimney filled with some sort of insulation the flue will still need periodic cleaning / inspection. How will this be achieved?]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18399&Focus=310115#Comment_310115 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18399&Focus=310115#Comment_310115 Tue, 27 Jan 2026 13:40:00 +0000 WillInAberdeen (Used this route to put a chimney balloon in ours!)

When there is a flue liner I think the register plate is cosmetic only, so an airtight seal is not needed round the stove pipe. But maybe OP wants to stop room air migrating through the vermiculite and condensing somewhere?]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18399&Focus=310120#Comment_310120 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=18399&Focus=310120#Comment_310120 Sat, 31 Jan 2026 10:14:59 +0000 gravelld
> When there is a flue liner I think the register plate is cosmetic only, so an airtight seal is not needed round the stove pipe. But maybe OP wants to stop room air migrating through the vermiculite and condensing somewhere?

Yes - definitely. If there isn't a seal between the register plate and the air tight layer, and the register plate and the flue, there will be a chance of air leakage. The chimney area beyond the register plate will not be air tight - it might be capped but not air tight.]]>