Options for levelling floor joists

Discussion in 'Carpenters' Talk' started by Ambienz, Mar 5, 2023.

  1. Ambienz

    Ambienz New Member


    I have a standard Vic Terrace property where many of the floors are warped (and bouncy) and Im trying to work out the best solution to levelling and firming them up. There are 2 rooms per floor, supported in the middle by a timber spine wall - bricks at either end. To make matters more complicated there is water UFH in each room (just more work) that I need to navigate around and will limit how much of the space between joists I can use. On the other hand there are suspended ceilings on many of the floors making it easy to deal with each joist individually without destroying the ceiling below.

    Is it possible / easy to lift up each joist and pad them at the ends to level the floor. Do these joists usually only span one room, so I don't need to worry about cutting them at the spine wall? How are they fixed at the spine wall end? I assume at the brick end they are bedded into the wall?

    Alternatively I could bolt a thinner piece of new timber (say 1 inch) to the current joists . I guess in a few I could also add a fitch plates to increase rigidity as well as noggins between joists. More materials and mucking around with UFH panels, but probably a better finish.

    Is there a better solution that I am not thinking about?

  2. arrow

    arrow Screwfix Select

    The joists normally crossover and overlap on the spine wall, therefore a joist for each room.
  3. Rosso

    Rosso Screwfix Select

    If there's not loads of plumbing and wiring going through the joists, you can simply sister new c24's to the original joists. Use the max depth of modern joist that will fit, glue and nail them to the originals. Even if you can only fit 2x6's in the space, fixed to the originals they will stiffen up the structure, and give you a level top surface.
    Assuming its not a listed property, It is up to you if you put the original floorboards back down, or scrap them and put caberfloor down instead. If the walls have settled irregularly, you will have to redo the skirtings as well.
    Yes, fit blocking or herringbone bracing between the joists at mid span, or every 8'.
    If there is a load of plumbers junk in the floor, sistering is not usually possible. In that case you have to cut furring strips, then glue and nail them to the tops of the existing joists- which whilst tricky , is ok on square cut joists. In many loder properties, the joists were axed straightish, and thrown in. There can be just a 3/4" bearing surface for the floor. Even more fun is to be had when the joists were not levelled one to the next, and the floor was levelled by relieving the undersides of the floorboards.
    By 1865, they'd got the hang of preparing timber, so if its a later vicky, it won't be too bad
  4. Mr Rusty

    Mr Rusty Screwfix Select

    I wonder if when the UFH was fitted someone removed the herringbone struts, and that's why the floor is bouncy. I've made this mistake myself in the past, not thinking they added anything significant to the floor structure.
    The Happy Builder likes this.

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