150x150 joist

Discussion in 'Carpenters' Talk' started by PK1, May 25, 2019.

  1. PK1

    PK1 New Member

    Hi everyone

    The structural engineer has specified a C24 150x150 beam for a project I'm working on. It's to prop up a chimney breast and the BCO is happy with this.

    But getting hold of a 150x150 beam in one piece is proving hard. Any thoughts on what the best solution here is? Bolting together three 6x2"? Or 6x4' + 6x2"?

    Secondary to that, this timber as well as the other pre-existing joists will slot into the webs of the new steels which are going in on either end of the room. Is using joist hangers compulsory or is notching the joists into the web acceptable? One to ask the BCO on Tuesday of course but I'm just trying to get a mental head start so I can plan next week.

    Many thanks
     
  2. chippie244

    chippie244 Super Member

    Bolting 3x6x2 should be fine and notching into web is standard.
     
  3. PK1

    PK1 New Member

    Thanks chippie
     
  4. PK1

    PK1 New Member

    Just had a measure up and because of the size of the steel, the base of the joists are going to come into the web about 50mm above the flange. Is it acceptable to prop them up with brick/timber?
     
  5. chippie244

    chippie244 Super Member

    I don't understand what you're saying.
     
  6. Pollowick

    Pollowick Screwfix Select

    Have you looked at Glulam beams? They are available in 150x135 and 150x180
     
  7. PK1

    PK1 New Member

    So the web of the steel is 203mm, the timber is 150. the bottom edge of the timber is not going to meet the bottom of the web, it'll be higher. The steel can't be inserted at a higher level because of the floor above. Side view would look something like below. Is it acceptable to prop the joist up with brick? upload_2019-5-25_11-49-25.png
     
  8. Pollowick

    Pollowick Screwfix Select

    Having a similar situation here, can I suggest you raise te floor 20mm or so - if you dont, getting services, cables, heating &c past te stell could be impossible!

    What is happening below? are the joists being covered/boarded?

    Go back to the SE/Architect and see if you could use thinner but deeper beams such as 225x???
     
  9. chippie244

    chippie244 Super Member

    What Pollowick said.
     
  10. PK1

    PK1 New Member

    Floor level above can't change. Ceiling height below can't change. The extra (3x6x2) beams are supplementing existing beams so the position of the beams can't change either. Services are fine as the steel doesn't span the whole room and there's space at either end.

    I can go for a smaller steel with a plate welded to the top but there's still going to be >10mm gap. Is it OK to pack this with slate?
     
  11. chippie244

    chippie244 Super Member

    I can't see a problem with running a timber along the web but personally I would steer clear of brick or slate.
     
  12. choppy111

    choppy111 Member

    Fit joist hangers to a 8x2, then sit the 8x2 inside the webbing and bolt it through the steel. Run your existing joists into that
     
    chippie244 likes this.
  13. KEVIN NAIRN

    KEVIN NAIRN Member

    I can't see the difference in sitting a joist on the flange of the steel, or sitting a joist on a piece of (good quality) wood on the flange of the steel, as long as it's the same width as the flange. If you use a timber batten to pack up the joist, make sure you drill holes through the underside of the flange and screw with csk screws, or the timber batten could start to move...
     
  14. KEVIN NAIRN

    KEVIN NAIRN Member

    I would get a long straight piece of hardwood (or 2 pieces) slightly bigger than 50mm (or whatever the gap is) and take to a joinery shop to put through their thicknesser. Won't cost much and beats faffing around.
     
  15. PK1

    PK1 New Member

    Thanks Kevin
     
  16. Pollowick

    Pollowick Screwfix Select

    One problem that you need to remember - is the flange flat or at a slight angle? You may find a difference of 3, 4, 5 mm between the lip and the inner thickness. The batten may need to take account of that.
     
  17. Greentram

    Greentram Member

    Most I-beams are UB/UKB sections with parallel flanges; older RSJ sections have a taper. Going back to PK1's diagram, I would size the packer so that the top of the joists is a little above the top of the steel so that if the joists/packer shrink a little you don't end up with a ridge in the floor.
     

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