Adjustable Floor joist noggin?

Discussion in 'Carpenters' Talk' started by raidingkilt, May 24, 2020.

  1. raidingkilt

    raidingkilt Member

    I guess so, there’s 3m high bedroom & 2 tiled bathrooms above.

    Dug out the SE report and he’s based it on c16, with sistered c24 (confirmed), I guess as worst case scenario.

    I’ll pop SE report (based upon verbal and photographic evidence) below:
    1. Joist check 1:
    Span = 4400mm + bearing = 4450mm

    190x44C16 + 150x44C24 @ 400mm c/c with the standard floor build up (not bathroom) has a selfweight of approx. 0.83kPa

    Under standard domestic floor loading (1.5kPa or 2kN point load)

    Joists are working at 78% of their structural capacity

    The main 44mm wide C16 joists require a supported length at bearing of 47mm

    Their deflection will be approx. 20mm. This is greater than the recommended limit of 14mm.

    No structural failure, just a serviceability failure (excessive deflection)


    1. Joist check 2:
    Span = 4400mm + bearing = 4450mm

    190x44C16 + 150x44C24 @ 400mm c/c with the standard bathroom floor build up has a selfweight of approx. 1.07kPa

    Under standard domestic floor loading (1.5kPa or 2kN point load)

    Joists are working at 84% of their structural capacity

    The main 44mm wide C16 joists require a supported length at bearing of 52mm

    Their deflection will be approx. 22mm. This is greater than the recommended limit of 14mm.

    No structural failure, just a serviceability failure (excessive deflection)


    1. Lintel check:
    Span = 2882 + bearing = 2950mm

    2No. 224x50

    Supporting one end of the 4.4m floor span (not bathroom) & 3.3m of plasterboarded stud wall lining above.

    Assuming C16+, timbers are working at 97.5% of structural capacity and 98% of deflection.

    They require 90mm bearing at supports.

    No structural failure, assuming C16+.
     
  2. Severntrent

    Severntrent Screwfix Select

    Ah!! different prob altogether, I have been working on the assumption that what we had was existing 195 x 47 c24 joists and they were within regs. Ignore everything I have said
     
  3. raidingkilt

    raidingkilt Member

    Doesn’t fill you with much confidence...
     
    Last edited: May 25, 2020

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