Joist hanger size help

Discussion in 'Building' started by jacko555, 14 Nov 2021.

  1. jacko555

    jacko555

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    Below are extracts from a SE plan. I'm planning on doing the work myself.

    I have some basic questions.

    For reasons, I can only get 75x200mm C24.

    1. Are 47x97mm (2x4) wall plates going to be big enough to secure 75x200mm (8x3) hangers? What size wall plate would you suggest for combination?

    2. Can you suggest a suitable hanger for the suggested wall plate size?

    3. Can you suggest suitable nails for the hangers?

    Bonus points for links to a place I can buy them online...

    Thank you
     
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  3. tell80

    tell80

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    Just me maybe but
    I call the plates that sit on top of a masonry wall, wall plates. they usuly take any birds mouth rafter cuts in pitched roofs.
    Ledgers are fixed to the vertical walls with eg M10 fixings.

    75mm x 200mm timbers are well hefty. Maybe you can reduce the section an use a different grade timber?
    What are you doing - fixing floor joists or roof rafters?
     
  4. jacko555

    jacko555

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    Thanks for the reply

    I'd rather implement as per the SE plans.

    As above, plans suggest 63x170 or larger, but for <reasons> 75x200 are easier to source.
     
  5. jks7492

    jks7492

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    Whats the floor span? The joist spacing they've specified is a bit odd...

    I'd go for a minimum 150mm deep timber bearer bolted to the wall to give enough depth to face fix a hanger to.
    Simpson Strongtie JHA270 hangers are available in different sizes to suit both 63mm and 75mm joists.
     
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  6. JobAndKnock

    JobAndKnock

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    Not just you - last three jobs where I've done structural work the s/e has referred to them in the same way.

    OP - I'd be asking the S/E why 375mm for joist centres. It doesn't match any sheet sizes available - unless the design calls for resillient bars to hold the ceiling and there is no form of flooring going on the top (otherwise you'll have to trim almost each and every sheet you install)

    AFAIK with a few exceptions the ONLY permissable form of fastening for joists hangers at present is the (sherardised) twist nail. The exceptions are this specialised joist hangers which are designed to work with specific screws supplied by the joist hanger manufacturer; you cannot use normal wood screws, drywall screws or any other type of screw (and if you do use those oddbals, keep the manufacturer's sheets as the BCO is almost certain to query them if he sees them)
     
    Last edited: 14 Nov 2021
  7. jacko555

    jacko555

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    These are sitting beneath, supporting undersized 2x7's at 400c/c. The 375 spacing let's each 2x7 sit in the middle of the new joist.
     
  8. ^woody^

    ^woody^

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    A wall plate sits on top of a wall, is not anchored, and why anyone would specify a stress grade for timber that won't be stressed is beyond me.

    The engineer should be specifying the type and size of hangers, as part of his design work.
     
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