Bathroom sub floor

Discussion in 'Tilers' Talk' started by thelondon, Oct 29, 2013.

  1. thelondon

    thelondon New Member


    I know sub floors has been covered alot, but I couldn't find my specific problem.
    Any help appreciated.

    I have a ground floor shower room which has been constructed the following way:
    concrete slab. 50x50 treated battens screwed down @ 400 centers with 50mm kingspan in between.
    In order to get the floor height to meet the entance floor height i need to add a sub floor of 28mm.
    So with that i purchased several sheets of 3.5mm and 25mm wpb ply.

    I have layed the first sheets of ply down (3.5 and 25mm on top) and screwed them down with floor tite screws every 100mm.

    with all this i have noticed a slight bounce\spring inbetween battens when walking over it. I got my wife to walk on too (as she is a bit heavier than me) and i could see the deflection in the board.

    Am i missing something here? I thought 25mm ply was supposed to be rock solid.
    I have 18mm t&g chipboard on the rest of the house on the same batten construction and that seems fine.

    is this a problem with regards to tiling (cracking etc), and any ideas on solutions?

  2. plane-it

    plane-it Member

    What happened? Did you get rid of the movement?

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