Wobbly floorboards - no wonder!

Discussion in 'Carpenters' Talk' started by fred812, Jan 6, 2021.

  1. fred812

    fred812 Active Member

    Having a go at the wobbly floorboards in our new place and this is what I found. I normally find that if I take it steady something pops in the old grey matter but I have to admit I'm a bit worried about getting myself into a situation where I need skyhooks. Anyone got any suggestions please before I mess up big time. Photo attached.
    Thanks.
     

    Attached Files:

  2. Jord86

    Jord86 Screwfix Select

    So the central joist is just floating after the pipework was installed? The removed floorboard spanned roughly 800mm, that correct?
     
  3. Could you take more out of the joists and hopefully lower the pipework
     
  4. fred812

    fred812 Active Member

    Not sure which of those two is the central joist, but don't think either is floating but maybe I'm misunderstanding floating? Yes the removed floorboards span roughly 800mm, bit more I think but only an inch or so.
     
  5. Jiml86

    Jiml86 Screwfix Select

    I’d say you may keep going and get them all up, then get some new joists in with hangers and plenty of noggins. Maybe put down ply on top and floor then?
     
  6. FlyByNight

    FlyByNight Screwfix Select

    If you look at the next board, there are nails on the mid line between the joists than can be seen. Has a joist been cut back? And possibly a nail hole up by the door opening.
     
  7. fred812

    fred812 Active Member

    Sorry for the ignorance. Would the new joists be left to right on the pic or top to bottom?

    Even then surely I still have a problem with the first (top in the pic) board thats been removed? There's just no joist to connect to. Unless I'm completely missunderstanding?
     
  8. Jiml86

    Jiml86 Screwfix Select

    My suggestion would be get all the floorboards off, then a new joist going top to bottom as you look at the pic. If you stick your head in the gap and look under the floor what’s there? Is there a cut joist?
     
  9. fred812

    fred812 Active Member

    Yes there's another joist going left to right there. 14" from the one going across the door opening at the top of the picture.

    Don't think a joist has been cut back but don't know really, only had the place a few weeks. Thought sorting out a wobbly board would be straightforward.
     
  10. fred812

    fred812 Active Member

    Can't see a cut joist.

    If I put a joist in top to bottom, I will still have to cut out for the 22mm pipes which will still leave me with an unsupported board won't it?
     
  11. Jiml86

    Jiml86 Screwfix Select

    Have you enough room for a sheets of ply down first?
     
  12. Jord86

    Jord86 Screwfix Select


    Leave the floorboards as they are. Don't concern yourself with joist hangers.

    Cut a new piece of joist material (whatever your existing is, 7x2?) and fit it tightly between the left and right joist so it butts tightly and squarely into the central previously cut joist where the gaping hole is. This is now acting as a trimmer joist. Screw it with 4 inch woodscrews into both left and right joists and stick three screws through the new trimmer into the old previously cut joist to secure it and tie the area back together. Now, using a sharp chisel or multi tool, cut back the piece of floorboard that's over the doorway threshold to give roughly three quarters of an inch for the new floorboard to bear on.

    Screw a piece of 2x2 against the right hand joist so you can fit the replacement floorboards without having to tuck them under the skirting, then the final part is to cut and fix a noggin (use the joist material) roughly in place of where the previous joist was cut, fitted between the joist you cut the flooring back on, and the new trimmer joist you fitted. Source some new boards to go back down or a piece of plywood. Done.
     
    Peterdevon likes this.
  13. Astramax

    Astramax Super Member

    Take the board out into the door recess, build up a noggin arrangement under the pipes and fit 22mm ply to suit the entire gap.
     
  14. Jiml86

    Jiml86 Screwfix Select

    Was that the only squeaky board?
     
  15. fred812

    fred812 Active Member

    Thanks Jord, need to read that a couple of times though.
     
  16. fred812

    fred812 Active Member

    I had been thinking along those lines. The existing boards are 18mm so was going to get some flooring grade 18mm chipboard from Wickes or B&Q.
     
  17. longboat

    longboat Screwfix Select

    20210106_192216.jpg Cut the board to approx follow the red line. Middle of joists on left side.
    Fit 3x2 or similar where the blue lines are. Fix with screws through floorboards for the middle two and also fix right hand side one to the joist. Cut out to fit round pipes as needed.
    Refit the board where yellow line is and fix at all points.
    Fill the remaining gap with plywood or P5 flooring whichever is easiest for you.
     
    Astramax likes this.
  18. Astramax

    Astramax Super Member

    Use the noggins with Chipboard ;)
     
  19. fred812

    fred812 Active Member

    it wasn't squeaky it was wobbly, literally wobbled and sank if you stepped on it, even with carpet and underlay it felt unsafe. No it wasn't just one board, but the one above the 22mm pipe was the worst.

    There's another area further down the hall where there's a similar issue but haven't started there yet!
     
  20. fred812

    fred812 Active Member

    I get that, many thanks for taking the time to set it out like that.
     

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