low-Pitched roof extension (14 degrees) versus double pitched with a Gully
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Would you choose low-Pitched roof extension (14 degrees) versus double pitched with a Gully

Poll ended at Sun Jan 29, 2023 4:19 pm
Low pitched roof (14 degrees)
0
No votes
Double pitched with gully
0
No votes
 
Total votes: 0
John Austen
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Joined: Sun Jan 15, 2023 3:43 pm

low-Pitched roof extension (14 degrees) versus double pitched with a Gully

by John Austen » Sun Jan 15, 2023 4:19 pm

Should I build a low-Pitched roof single story rear extension (14 degrees) versus double pitched with a Gully. There are advantages and disadvantages to both. I have an existing single story rear extension with a pitched roof, and I can add another next to this with a gully in-between, or I can take the pitched roof off the existing extension and put a low-pitched roof to cover the existing extension and the new extension( aesthetically this may look better) I believe the 2 pitched roofs would be a cheaper option, because I already have a pitched roof in place. I have heard there maybe drainage issues with a gully, but there are drainage issues with a low-pitched roof too. It is north facing and I don't live in a coastal area. There are tiles designed for this low degree roof profile which I could use. I also want to fit 2 roof lights (Velux) as well.
These are the 3 possible designs, but not sure whether I can have triple sliding doors, in terms of internal roof support, as the internal area is an open space. Any advice please?
in terms of costs, I would have thought it would be less expensive to build an adjacent pitched roof, than remove a pitched roof and replace the whole extension with a low pitched roof with specialist tiles from Sandtoft for example. I have also read that to avoid leaks in the future with low pitched roofs, the builder should do the following steps
OSB
Torch on
cross batten
felted
Battened
Anyone with experience of using these low pitched roof tiles?
Attachments
double pitched roof with patio doors
double pitched roof with patio doors
Low pitched roof
Low pitched roof

stoneyboy
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Re: low-Pitched roof extension (14 degrees) versus double pitched with a Gully

by stoneyboy » Mon Jan 16, 2023 11:14 pm

Hi John Austin,
If you can afford the extra go for the single pitch. Sandtoft interlocking tiles are ok at 14deg as long as the overlap is as specified. Check whatever roof windows you use suit the low pitch and go for separate windows to reduce the width to be drained at the top of the windows. If you choose Velux they do a special flashing kit to minimise water ingress.
A valley gutter will always be a potential leaker, especially if there are trees in the area. No need to fit osb, breathable felt on rafters with battens and tiles will work fine.
Regards S

John Austen
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Labourer
Posts: 3
Joined: Sun Jan 15, 2023 3:43 pm

Re: low-Pitched roof extension (14 degrees) versus double pitched with a Gully

by John Austen » Wed Jan 18, 2023 2:55 pm

Thank you very much for your valuable advice, \i will pass this on to my builder

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