afternoon all, hope some of you folks can advise me on this (sorry it's a bit long).
I have a flat roof currently being constructed - the bottom layer of felt has been torched on to give me some basic waterproofing and the roofers are due back soon to finish the job. I'm installing a wood burner as part of this project and the flue has to go through the new flat roof. The flue is not yet in position, nor is it likely to be when the roofers return - not a great situation I know, but I want to plan for the flue as best I can. The flue will necessarily be quite close to the edge of the flat roof where it abuts the main house wall. There are complications;
1. the near edge of the flue will only be 80mm from the wall/edge of flat roof. Also, there is some upstand ventilation detail down the edge of the flat roof which makes everything very tight space-wise. The roofers were talking about handling this part of the roof 'in liquid' (whatever that means?) but I don't think that will work because of point 2 below.
2. the BCO is hot on the topic of clearance between flue and combustibles. It's a twin wall flue and I understand I need to clear all timber within 50mm of the flue.
The best idea I've come up with so far is to identify the rectangular area that gives me the 50mm flue clearance. It's a 200mm flue so this will be approx 300mm square. I'd then divert the upstand ventilation around three sides of this square and cut the timber deck away within it. To make things watertight I would use a flat roof lead flashing for a 200mm pipe. The ones I've seen have large bases which could be worked into the masonry on one side, and over the upstands on the other three sides. The lead would need some support but I could do this with metal straps or some other non-combustible material. Could be tricky to get this right and I might end up needing a bit of bespoke lead work, but it's the only way I can think of satisfying the BCO and being watertight. What do you think? Any better ideas greatly appreciated, TIA
Nick
I have a flat roof currently being constructed - the bottom layer of felt has been torched on to give me some basic waterproofing and the roofers are due back soon to finish the job. I'm installing a wood burner as part of this project and the flue has to go through the new flat roof. The flue is not yet in position, nor is it likely to be when the roofers return - not a great situation I know, but I want to plan for the flue as best I can. The flue will necessarily be quite close to the edge of the flat roof where it abuts the main house wall. There are complications;
1. the near edge of the flue will only be 80mm from the wall/edge of flat roof. Also, there is some upstand ventilation detail down the edge of the flat roof which makes everything very tight space-wise. The roofers were talking about handling this part of the roof 'in liquid' (whatever that means?) but I don't think that will work because of point 2 below.
2. the BCO is hot on the topic of clearance between flue and combustibles. It's a twin wall flue and I understand I need to clear all timber within 50mm of the flue.
The best idea I've come up with so far is to identify the rectangular area that gives me the 50mm flue clearance. It's a 200mm flue so this will be approx 300mm square. I'd then divert the upstand ventilation around three sides of this square and cut the timber deck away within it. To make things watertight I would use a flat roof lead flashing for a 200mm pipe. The ones I've seen have large bases which could be worked into the masonry on one side, and over the upstands on the other three sides. The lead would need some support but I could do this with metal straps or some other non-combustible material. Could be tricky to get this right and I might end up needing a bit of bespoke lead work, but it's the only way I can think of satisfying the BCO and being watertight. What do you think? Any better ideas greatly appreciated, TIA
Nick