RSJ over garage opening

Discussion in 'Builders' Talk' started by SuperPav, Oct 11, 2018.

  1. SuperPav

    SuperPav New Member

    Hi all,

    Building a double garage (approx 27sqm so BC not interested). It's 5.7 x 5.7 from concrete block single skin laid flat, with an opening of just under 4.0m.

    My question is around the lintel/RSJ over the opening span.

    I'm thinking of just getting a 4200mm 254 x 103 x 22kg RSJ
    The only load on the RSJ will be my roof joists (250mm deep easijoists supporting a flat roof)

    Does that seem manly enough? It's certainly deeper an RSJ section than many I've seen on older double garages...

  2. PhilSo

    PhilSo Active Member

    What is the joist spacing?
  3. SuperPav

    SuperPav New Member

    joist spacing will be 400mm according to calculations by the easijoist people. The joists are running perpendicular to the RSJ over the opening but I suppose I could run them parallel if it would help? In that case the RSJ would be holding barely anything up... The building is square, so no issues with the joists spanning the other way.
  4. Jord86

    Jord86 Well-Known Member

    If the opening is 4m I would think you would need a 4.4m RSJ, 200mm bearing either end rather than 100mm.
    SuperPav likes this.
  5. SuperPav

    SuperPav New Member

    It's actually 3860mm, so I would have 150mm bearings either side, but that's a fair point, might as well go for 4.4m not like it will make much difference to weight or cost.
  6. stevie22

    stevie22 Active Member

    Run the joists wall to wall then you don't need a steel. Simples!
    SuperPav likes this.
  7. Richard_

    Richard_ Active Member

    Don't use a steel beam. It's a UB by the way, not an RSJ. A bit like referring to a consumer unit with RCDs as a fuse box with fuses.

    If you turn the joists to span side to side then the UB won't be carrying any load. Zilch. Nada. You would have a slope across the face of the garage which might catch your eye, but you can hide that with your fascia - I like to create a small upstand on the non draining edges of flat roofs anyway so yo can make that a perfect sweet flat line.

    The only issue is your garage door. A long span garage door will need a head restraint, and you'll need some way of cladding the reveal soffit. So I'd double up the joists over the door and fix OSB to the soffit to create a solid box for fixing your door and fascia/eaves cladding.

    I presume Easijoist are providing standard details for wallplate and eaves details? Don't forget to make sure the wall plate is tied down!

    12-10-2018, 09:45 Office Lens.jpeg
    SuperPav likes this.
  8. SuperPav

    SuperPav New Member

    Brilliant, thanks both who suggested just turning the joists to run across. No idea why I didn't think of it before. This has just saved me a lot of hassle!

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