combi flue through a flat roof

seneca · 5 Oct 2006

Is it possible to have the flue of a combi boiler going through a flat roof? I am considering having one fitted, but wanted to know whether it could be reliably done without a leak. Some installers advise against it becuase they say it is tricky and prone to leaking, damaging the boiler in the process. Is this the general opinion, or will there be installers who don't mind going through flat roofs? What are the problems, if any?

thanks.

chrishutt · 5 Oct 2006

No reason why not in principle, but as you say it is important to create a good seal to prevent water getting into the roof structure. How difficult that is depends on the materials used for the roof.

seneca · 5 Oct 2006

There's not a problem with the actual flue design is there? I have seen seen them coming through people's walls and they are short, stubby pipes. I presume a different kind would have to be fitted through a roof, something with a cover to stop rainwater going directly down. Are there different attachments that can go on the end of a flue, and are they any good.

thanks.

Alfredo · 5 Oct 2006

You need the "Vertical Flue Kit" to go with your boiler. Flat roofs do not present an installation problem as such, but in practice they can be problematic due to pooling of water on them. Making a hole in any flat roof makes me nervous .

Alfredo

Nige F · 5 Oct 2006

just knock up a lead slate and bed it to the roof using the same material the roof`s covered with and make a collar for the flue to deflect water over the slate like on a soil pipe....then seal with sani. silicone

Agile · 6 Oct 2006

Nige F said:
just knock up a lead slate and bed it to the roof using the same material the roof`s covered with and make a collar for the flue to deflect water over the slate like on a soil pipe....then seal with sani. silicone

Dont know about that!

The only problem is that many installers just dont know how to make a water tight joint with a flat roof.

It takes me TWO hours to make that connection! I bed the cover onto the flat roof with hot bitumen and the cover the top with over lapping sticky composite repair tape warmed up unless its very hot weather. Only then can I guarantee it as water tight.

Sometimes I go to other installers who have done a real bodge with silicone designed for baths!

Tony

Nige F · 6 Oct 2006

bugger, I thought there`d be a market for making lead slates in me garage

seneca · 11 Oct 2006

Thanks everyone. Most helpful indeed.

pampers · 11 Oct 2006

Avoid it if there is any other possible way ,its just asking for trouble.

If we really have to we get the customer to agree to get a roofing company to make the roof good around the slate so when it leaks in time its between them and the roofers.

Biggles.. · 11 Oct 2006

Gave up going for the warmfront grant!Let me guess your house or your mothers.As was explained in your prevoius post flues can go through flat roofs but some companies wont due to the problems introduced.

seneca · 11 Oct 2006

"Gave up going for the warmfront grant!"

On the contary, after a phonecall they agreed to reassess the application, as they have had a number of similar complaints from other clients with regards to the assessor.

"As was explained in your prevoius post flues can go through flat roofs but some companies wont due to the problems introduce"

Yes, it was much better explained on this thread. Seem to be a reasonable bunch here. Decent individuals without suspicious minds, who don't feel the need to hurl abuse. My faith in plumbers and engineers has been restored.

I've posted a question about lawnmowers on the gardening forum, so you can now go there and completely miss my point again.

Agile · 11 Oct 2006

seneca said:
Seem to be a reasonable bunch here. Decent individuals without suspicious minds, who don't feel the need to hurl abuse. My faith in plumbers and engineers has been restored.

I am sorry if we have not met your expectations of hurling abuse!

Quite often I am accused of being sharp because I say it as it is whatever the circumstances in accordance with my well balanced Libran sense of fairness.

Tony

ChrisR · 11 Oct 2006

well balanced

Chips on both shoulders??

Biggles.. · 12 Oct 2006

I am genuinely glad you have got what you want out of wamfront. You now have the free boiler exactly where you want it.Not everyone is so lucky, most people have to pay for those things.
Cant help you with lawnmowers im affraid, dont know nowt about em.

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combi flue through a flat roof

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