1. Visiting from the US? Why not try DIYnot.US instead? Click here to continue to DIYnot.US.
    Dismiss Notice

best products to use over joists before tiling ?

Discussion in 'Tiling' started by bmx, 16 Oct 2015.

  1. bmx

    bmx

    Joined:
    3 Sep 2005
    Messages:
    66
    Thanks Received:
    0
    Country:
    United Kingdom
    Hi i have stripped a bathroom floor that was rotten and wanted to know the best way to re board it as i plan on tiling the floor?

    the joist centres are 450 and a few are at 400.

    is there a product like cement partial board that will do the job in one? or do i need to use 18mm ply then the hardie stuff?
     
  2. Paul C.

    Paul C.

    Joined:
    1 Oct 2015
    Messages:
    131
    Thanks Received:
    18
    Country:
    United Kingdom
    You'll need to board the floor out first with moisture resistant chipboard (the green stuff) or 18mm WPB Ply. Overboard that with the 6mm hardie backer or a further layer of 18mm ply. Whichever you go for, the overboard will need to be screwed down at 300mm centres (this is the recommendation from British Standards BS5385), and that should be good to go. But as it is a new substrate and it will take time to settle, I would seriously consider using a decoupling membrane to cater for lateral movement.

    Any Ply or chipboard, would need to be sealed with an SBR Primer on the back and sides to prevent distortion from atmospheric change.

    In your situation, over boarding is a MUST. your joists are too far apart so there would be too much deflection regardless of the board type or thickness you choose.
     
  3. Sponsored Links
  4. bmx

    bmx

    Joined:
    3 Sep 2005
    Messages:
    66
    Thanks Received:
    0
    Country:
    United Kingdom
    ok thanks is there a way of doing it so i can just tile onto the floorboard, i.e. if i pt an extra joist in between every joist to make the centres 225 ish and use flexible adhesive onto a new green chipboard floor ??
     
  5. ree

    ree

    Joined:
    6 Feb 2014
    Messages:
    3,193
    Thanks Received:
    447
    Location:
    California
    Country:
    United Kingdom
    There's no need for any extra joists: 400mm is 16" the traditional spacing for centres. 450mm is neither here nor there - no deflection will take place.
    Neither are two layers of 18mm necessary - we've often laid tile on 22mm T&G floor boards or ply, using flexi adhesive and flexi grout. Not recommended but it works.
    Green T&G chipboard is fine but any kind of WPB is an unecessary expense.

    18mm with 6mm backer board will work fine - nothing else needed.
     
  6. DIYnot Local

    DIYnot Local

    Joined:
    3 Sep 2019
    Country:
    United Kingdom

    If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

    Select the supplier or trade you require, enter your location to begin your search.


    Are you a trade or supplier? You can create your listing free at DIYnot Local

     
  7. Sponsored Links
Loading...

Share This Page