Adjustable Floor joist noggin?

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

  1. raidingkilt

    raidingkilt Member

    I’m trying to fix a floor with bad displacement, but the first and last gaps between joists and walls are filled with services (including a soil pipe).
    As it’s so tight I can’t slide any nog’s in or make herringbone style ones either.

    I’ve got noggins between all the other joists at 1/3, 1/2 & 3/4 positions, but without tying to walls, hasn’t made much improvement.

    any ideas? I was looking for maybe something like expanding metal bars, that can be slid in, attached, and then tensioned???? Such a thing exist?

    Someone totally cocked this floor up, the joists all have some extra timber sistered to original joists, but due to services, they haven’t run them to wall plates.
    Structural engineer said floors at 90% but about 10-20mm displacement. ‍♂️
  2. Severntrent

    Severntrent Screwfix Select

    Could try and mackle up your own by using a turn buckle with some wooden end plates fashioned to take the eyes and instead of shortening the turnbuckle to tension things, lengthen it to expand and compress between joists, but I guess it depends what room you have.
    Out of interest why have you not tied into walls?
  3. raidingkilt

    raidingkilt Member

    Not sure how you mean?

    It’s all timber frame internally, so joists sat on timber wall plates.
    Soil pipes are running parallel to first joists, So can’t tie 1st joist to wall via a noggin as soil pipe in the way. Joists 2-11 all tied together with 3 noggins each, but between 11 and wall, there’s mountain of electrical.

    So I’ve got 1-11 fixed together, but wall to 1 & 11 to wall = no noggins. Proper **** show.
    Plus spark ran all electrical within first 1/4 of joists.. at both ends. Property’s about 20 year old, so not sure when regs changed regarding holes and locations.
    Last edited: May 24, 2020
  4. Severntrent

    Severntrent Screwfix Select

    Gotcha, totally misunderstood posting, must be to early for me, good luck.
  5. raidingkilt

    raidingkilt Member

  6. WillyEckerslike

    WillyEckerslike Screwfix Select

    If you can get those in, can't you get some 50x50mm herring bones in?

    Can you post a picture(s) of the areas where you're trying to tie? I would have thought that some 12mm threaded rod, some wall mounts/back plates and possibly some extended joining nuts would give you the greatest flexibility to work around the existing pipes/cables.
  7. raidingkilt

    raidingkilt Member

    I’m not sure I can get my linked jacks in, but as they’re adjustable, more scope to slide around and over soil.
    There’s maybe 20-50mm above soil, but can’t get much past them, and then no way to get it in tight, to push/pull row of noggins together.

    there’s about 18mm below soil, I’ve added some plywood in to support hot water as it was just flapping in the wind.


    I’d ideally need to get jacks/bolts in the top and bottom to stop joist twisting.
  8. Abrickie

    Abrickie Screwfix Select

    Have you looked at the steel herringbone struts ;)
  9. raidingkilt

    raidingkilt Member

    Yeah there’s some in already, see photo above, but they’re only in open sections, and to be honest, don’t do much. But again, the soil pipe leaves no space for them
  10. wiggy

    wiggy Screwfix Select

    I would give up trying to get anything in there its not going to make a difference.
    Jord86 likes this.
  11. raidingkilt

    raidingkilt Member

    You think? I have thought of giving up, but It’s pretty **** at moment.

    Bar jacking up whole floor, cut all the electrical and somehow slide in some new joists.. I don’t really know what else to do. So end nogs was last dip into trying to improve bounce.

    I thought whole point of noggins was to make the whole floor one, by knocking shims in, against nogs at wall ends, to pull all the joists tight?
  12. wiggy

    wiggy Screwfix Select

    What is the span of those joists
  13. raidingkilt

    raidingkilt Member


    They’re within regs.. someone’s messed up somewhere, as they’ve sistered 3m X c24 to exsisting joists.

    Structural engineer recently had a remote look (via photos and measurements) and guesstimates deflection of around 20mm. Feels more than that, and there’s about 20mm sag in centre of room.
    Engineer recommended supplementary joists, but budget simply doesn’t stretch as would require re-wire and jacking up of bedroom and 2 bathrooms... all to just stiffen the floor.
    Engineer said it’s not going to fall down, there’ll just be plaster cracks and feeling of bounce.
  14. wiggy

    wiggy Screwfix Select

    Is the floor on upstairs?

    The 3m joists fall 1.4 from any bearing?

    How much of an issue is this for you?
  15. raidingkilt

    raidingkilt Member

    Yeah Upstairs, it’s master bedroom & 2 bathrooms.

    3m sisters fall short of bearing... they obviously added it after 1st fix, so couldn’t run sisters to bearers as cabling in the way.

    it’s bit of pain, Door and lamps rattle when you walk across floor, roll over in bed causes door to rattle, and cosmetic cracks keep appearing in plaster.
    As we’ve ceiling down currently (due to leaks) just trying to make it best it can be.
    Issue doesn’t warrant the cost or upheaval of additional joists being added. But i had hoped noggins and fixing to wall would have improved it slightly.
  16. Severntrent

    Severntrent Screwfix Select

  17. wiggy

    wiggy Screwfix Select

    Stick up another photo of the whole ceiling if you can.

    I take it its chipboard floor above?
  18. Jord86

    Jord86 Screwfix Select

    Noggins won't sort out bounce and rattling doors if the joists are undersized. Unless I missed it,you didn't state the dimensions of the joists.
  19. G Roo

    G Roo Member

    If you can get to the joists above then run some 2 metre restraint straps across joists from the wall. Failing that, since you have the whole ceiling down, 3 rows of steel herringbones the forked end type, but fit them horizontally. Make sure to make em tight. You may need to raise the 15mm polypipe. With all the joists tied together in compression across the whole width of the room that should stop some of the flex
  20. G Roo

    G Roo Member

    We can't see the rest of the room so obviously if you can get some bracing in vertical then do that

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