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Is this birdsmouth type cut ok?

Discussion in 'Roofing and Guttering' started by Adviceseeker78, 23 Jun 2019.

  1. Adviceseeker78

    Adviceseeker78

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    My builders seems to have done quite an irregular birdsmouth cut - is this acceptable for building regs?

    This is for a single storey extension with roof angle at 16 deg - wall to wall length is 3 metres so span is just over 3m.

    Thanks
     

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  2. noseall

    noseall

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    No. That is terrible and amateurish. We try and limit the cut to 25% of rafter depth. You seem to only have 25% remaining.:eek:

    If there were joists sitting on that WP they would have rafter material protruding below the ceiling line. Horrendous. Sack the roofer and buy some new rafters.
     
  3. Adviceseeker78

    Adviceseeker78

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    Arrgghhh. Thanks for posting. This is what another builder mate of mine said.

    The guy who did this is my main builder. Obvs very worried about the quality of the other work now.
     
  4. ^woody^

    ^woody^

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    You could add some ply gussets to reinforce the rafter.

    Nail plates may do the same thing, but you'd need the supplier or an engineer to confirm.
     
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  5. Adviceseeker78

    Adviceseeker78

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    I think the builder did it this way to get the angle for the roof tiles. Is there a building regs standard for this?
     
  6. ^woody^

    ^woody^

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    No. Building Regs are not standards.

    They're will be BS or EN standard, or the NHBC Standards may mention this or refer to the relevant BS/EN standard.

    Or you could get someone to calculate the loading and stress at the bearing and that will do.
     
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  7. Adviceseeker78

    Adviceseeker78

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    I’ve seen this image - maybe this is the plan to reinforce it this way? Would this work?
     

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  8. ^woody^

    ^woody^

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    No. Google for plywood gusset and look at the images, and you'll need to cut two per rafter and scribe it around the wall plate to strengthen the rafter and also give it a better seat on the wall plate.
     
  9. noseall

    noseall

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    It begs the question: If they have allowed the rafter material (that which would be ordinarily removed on a regular BM) to protrude down into the room, why they never set the WP at that height, i.e. lower?
     
  10. Leofric

    Leofric

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    Some say the birdsmouth cut out should be a maximum of 1/4 the depth of the rafter , others say 1/3. Too much has been cut out of your rafters and they need reinforcing as others say.
     
  11. Notch7

    Notch7

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    Prob because the wall went up, then the wall plate went on, then he scratched his head and wondered how to get to 16deg without any rework.
     
  12. Notch7

    Notch7

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    He could notch the joists too :ROFLMAO:
     
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  13. catlad

    catlad

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    That isn't worth pi$$ing around with, just start again.
    Preferably with another builder!
     
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