Are you concerned about getting a vertical boiler flue through your roof in case it causes a leak?
I don’t blame you. If you’ve ever had roof problems before, you’ll be aware of how expensive repairs can be. And the thought of drilling a hole through your roof can be… well, nerve-wracking! Everyone wants their home to be wind and watertight, and no-one wants the hassle – or expense – of getting out a contractor to fix someone else’s mistakes.
Especially if you live in a shared tenement flat, where there’s also a concern of causing damage to your neighbours’ properties! After all, you wouldn’t want to find a leak six months later, and everyone starts blaming you for getting a flue fitted.
With over 20 years’ of experience as a heating engineer, I’m going to explain all you need to know about installing a vertical boiler flue the right way. So, you won’t have to worry about leaks!
Can installing a vertical boiler flue cause leaks in your roof?
Think of it this way; if everyone who installed a vertical boiler flue through a roof had to fix leaks right, left and centre then no-one would install them at all. However, if a vertical flue is badly fitted, then yes, you could have a leak on your hands. Especially if it’s not sealed properly.
Most installers or roofing contractors will use a slate piece, or a metal or lead piece that fits onto a flat or pitched roof, with a gromit where the flue pipe goes through. This is normal, but the most important thing to remember here is that it won’t seal if you do this while it’s raining, especially on a flat roof.
That’s because installers usually use a tar-type tape to stick it. This is melted down using a gas bottle, which welds the flue join to the flat tar roof. Unfortunately, this needs a dry surface in order for it to stick properly, so if it’s raining (even light rain), it’s always better to wait a day and ensure the job is done correctly to prevent any leaks from occurring.
It’s not unusual for heating engineers to hire in a specialist roofer to help ensure there will be no leaks. In fact, we always do this on jobs with flat roofs, or when a roof is a high pitch.
Can it ever be dangerous to install a vertical flue through your roof?
Again, it shouldn’t be. If you hire a reputable, experienced engineer then they will fit your flue to follow all Gas Safe regulations. Different flues and boilers sometimes have different specifications. For instance, some flues can run up to 6 metres, and others up to 12 metres.
A reputable engineer will follow manufacturer’s instructions when fitting your vertical boiler flue, with respect to the length, and other things currently on your roof. For instance, your flue should be fitted a good distance away from other flue pipes, and chimney breast walls etc.
You do hear horror stories of badly fitted flues from time to time. However, this isn’t really something you should worry about, as long as you choose a reputable, established Gas Safe Registered heating engineer.
After all, they’d have a string of terrible reviews and soon go out of business! They wouldn’t get away with regularly putting their customers in danger.
Advice from an experienced engineer
If you choose a Gas Safe registered engineer, you should not have any issues. However, if you’re in any doubt, ask your engineer what they plan to do. They should be happy to answer any questions you may have about the job.
I had a customer recently who was very worried about where his flue was going, and how it would be installed. We sat down for 15 minutes while I showed him the regulations, and explained why we decided to take it 500mm away from where we originally thought.
He had a semi-detached house, and so we decided to move the flue away from the centre-line. This is because we didn’t want to put the flue on the part that joined him with his neighbour. All it took was a double bend that went specifically over his roof. This was so that on the off-chance anything DID go wrong, it wouldn’t affect his neighbour. He was very cautious.
If you have any doubts or potential issues (such as if you stay in a block of flats), or there’s been any works on your roof, let your engineer know. They may want to get a specialised roofing contractor in first. This is so they can survey the situation, and take photos and documentation of the state of the roof before the flue is fitted.
This is to protect you AND your heating company if there were any other issues down the line.
Conclusion
If you’re worried about your vertical boiler flue going through your roof, don’t be. Just ensure you speak to your engineer and check exactly what they’ll be doing. Any reputable engineer will be happy to answer your questions. And don’t be surprised if they call in a specialist roofing contractor to help!
Got any other questions about installing a vertical flue through your roof? Let me know in the comments’ section. I’m always here to help!
