Adjustable Floor joist noggin?

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

  1. raidingkilt

    raidingkilt Member

    [​IMG] [​IMG] [​IMG] [​IMG] [​IMG]

    upstairs is chipboard, over dry scree and UFH pipes, then 9mm plywood sat on joists.
     
  2. raidingkilt

    raidingkilt Member

    Within regs in terma of span v size v spacing.

    so 4400 span, 45/47 x 195, 410 spacing
     
  3. Jord86

    Jord86 Screwfix Select


    Off a rough rule of thumb your joists are undersized for the span, hopefully Severntrent can give you the hard figures.
     
    Deleted member 11267 likes this.
  4. wiggy

    wiggy Screwfix Select

    I would replace that line of metal herringbone and replace with a solid tight noggin.
    I would question weather or not timber connectors where used on the sistering timbers (not that they are doing anything but might be moving against the main joist).
    Other than that you could trying ripping up the chipboard and glueing and screwing 18mm tg4 ply down
     
    G Roo likes this.
  5. raidingkilt

    raidingkilt Member

    Sadly Can’t get above as UFH upstairs.

    With soil pipes, no way of getting any herringbone design struts in, metal or timber.


    Specs I’ve seen say they’re right on limit. 47x195x400 c24 =4.39m.. I get 4.4, it might have been 4.39 when installed.
    It’s not good which ever way you look at..
    Structural engineer said they were working at 84% and won’t fail, but not pretty.
    Stuff likes this totally ****** me off, spend a few extra ££ and you’d have no issues what so ever.
     
  6. Jord86

    Jord86 Screwfix Select


    Welcome to the building industry :cool:
     
  7. raidingkilt

    raidingkilt Member

    Thanks for replies.

    I’ve also been thinking the centre line is doing bugger all. As they weren’t installed initially, they don’t go over top of joist. For ease of life, was simply going to add nog run adjacent to the metal herringbone.

    Don’t know what you mean by timber connections of sisters c24? They have been attached with bolts, staggered, and have the teeth/jagged washers between joist and sister. These were all lose, but not much scope to tighten as bolt head just sinks into the dry wood.

    kinda a whits end with it..
     
  8. wiggy

    wiggy Screwfix Select

     
  9. raidingkilt

    raidingkilt Member

    Just a ******* when it’s your own house!

    im starting to think this might have been either self build or cheapest of cheap tradesmen, bar electrics... everything is done pretty poorly.

    we found a 10 year leaking shower (hence the ceiling down at moment) and soil pipe was propped up on wood, live cables buried in the wall and tiles with not even 10% coverage on.

    really thankful they had a decent spark in.
     
  10. wiggy

    wiggy Screwfix Select

    Timber connector
     

    Attached Files:

  11. raidingkilt

    raidingkilt Member

    Yup that’s the ones. They’ve got them between sister and joist. But as bolts were installed staggered in a /\/\/ fashion, the sistered c24 has warped and cupped.

    I had thought about loosen bolts, pop large washers on, and use some of the egger joist glue and retighten.
     
  12. wiggy

    wiggy Screwfix Select

    Get you dad to do them up properly. :D:D:D:D:D
     
  13. raidingkilt

    raidingkilt Member

    It’d prob be more like my grandson!

    in all seriousness, the sistered c24 is pretty brittle (bone dry with all the UFH, so if you go turbo, bolt either pulls through or spins.
     
  14. wiggy

    wiggy Screwfix Select

    Well keeping it on the cheap I cant see any other options.

    Stick a stud wall under it it. Divide the room below? that would be fairly cheap.
     
  15. Severntrent

    Severntrent Screwfix Select

    My tables 2004 edition (current ones 4th edition 2014) show47 x195 will span 4.55m with dead load not more than 0.25kn/m2, 4.36m span with dead load not more than 0.5kn/m2 , 3.92m span with dead load not greater than 1.25kn/m2
    Doing specific calcs for beams show that BM at 82% (so in line with your SE), and deflection just on the limit at 13/14 mm (as would be expected because this would be limiting factor in the tables as opposed to actual) beam strength
    So unless you have a loads of furniture in your bedroom or your floor construction is very heavy everything seems to checkout. The only thing that I could think of causing such a problem is the joists are not actually C24, putting C16 in the calcs puts the deflection at 18mm but the floors would have collapsed. All very strange.
     
    Jord86 likes this.
  16. wiggy

    wiggy Screwfix Select

    You have ufh and screed on top?
    That's some weight
     
  17. raidingkilt

    raidingkilt Member

    yeah that’s my major concern, the Structural engineer survey was done remotely and I guess he took same line of thought. If it was c16.. it’d have fallen down.
    It’s got two bathrooms as well on top, so it’s not just a bed.

    guess it’s probably time and find that money tree.
     
  18. raidingkilt

    raidingkilt Member

    Screed in loosest possible term, it’s like a 6:1 mix, basically sand, about 20-30mm thick.
    But yeah, some weight. :mad:
     
  19. Severntrent

    Severntrent Screwfix Select

    I assume its a 25mmish biscuit screed type of set up which would work out at 0.2kn/m2, plus 0.1kn/m2 for floorboards which would put us in the 0.25-0.5kn/m2 dead load bracket?
     
  20. wiggy

    wiggy Screwfix Select

    + the water
     

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