Floating Bathroom floor???

Discussion in 'Tiling' started by glock339, 10 Jun 2011.

  1. glock339

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    Hi I am about to start work on a ground floor bathroom that currently has an old concrete deck(no DPM or insulation etc). I'd like to raise the floor a bit anyway to make it level with the adjoining room so I was thinking of: laying down a DPM, then some 60mm kingspan boards, then clagging 10mm tile backer boards on top, tapping them etc as it will be a "wetroom" set up and then tiles on top.

    This is the only method I have managed to find on the old Google search so far which applies to a set up like mine but I would be a bit worried about the stability of this method. Would there still be any kind of possible movement, even if I staggered all joins in the boards? Would I not need to lay down some 60mm timber strips to screw the backer board joining edges to or would I need to mess about laying ply sheets as well??? :confused:
    I can’t seem to find any info online so any help would be much appreciated thanks! :D
     
  2. glock339

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    Anyone? :)
     
  3. mypetearthling

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    Try posting this in the tiling section, some of the guys there may have come across this setup before, and should be able to give you more advice on the wet room thing. If you ask the mods nicely they'll move it for you. :D


    K
     
  4. glock339

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    Cheers for the info marra ;)
     
  5. Richard C

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    Tiling onto a floating floor is definitely not a good proposition unless you can provide support back to the concrete deck to make it rigid; you will run a very high risk of tile failure. You will also need a lot more support than 10mm tile backer boards over the Kingspan & some seriously expensive latex based tile adhesive; & then it still might not work :cry:
     
  6. lancenotalot

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    What about dpm then 50mm sq battens fixed through into concrete to form joists,insulate between with 50mm kingspan or similar then overboard with 18mm ply fixed at 300mm centers.

    This should be solid enough to tile over.
     
  7. glock339

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    Thanks for the responses :D

    O dear I suspected I'd be messing on with battens and ply sheets etc :(

    So what are the main problems with backerboard stuck onto rigid insulation, would the kingspan eventually compress under the weight of people traffic, or is it mainly to do with the insulation not being secured to the concrete underneath & perhaps lifting/flexing? I'm struggling to get my head around it! :LOL:
     
  8. Richard C

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    60mm Kingspan will be rigid to a certain extent but will still flex too much for conventional tile adhesive, the tile base also needs to be physically fixed to the floor or movement will cause it to crack.

    I note your looking at 60mm insulation with a backer board; Marmox
    http://www.insulationexpress.co.uk/Tile-Backer-Board/Marmox-Waterproof-Insulation-Boards.htm
    is a proprietary insulated tile backer board & would be a much better bet but only goes up to 50mm, probably for reasons of flex. Personally I still wouldn’t chance it; I'd lay 50mm wide timber battens at max 450mm centres fixed off the concrete deck, insulate between & lay a minimum 18mm WBP floor over that.
     
  9. glock339

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    Yes I seen this stuff which is what made me wonder if rigid insulation/backerboard dose compress at all with a decent sized tile stuck to it, thought a company like Marmox would have done their research?



    Yeh I already have a load of 60mm Kingspan 8x4 boards so was wanting to use them as it will also bring my floor up to the height I want it (inc tiles etc). So... I'm thinking I mite lay down some 60mm deep battens (to match the Kingspan depth) at 400 centers & 18mm ply on top unless anyone says any different???

    I was wanting to lay a DPM sheet on top of the concrete, obviously this will be getting punctured by lots of screws holding the battens down if I use this method! Will a squirt of silicone down the holes before inserting the screw do any good here or will this completely nacker my DPM?

    Cheers.
    Gary.
     
  10. lancenotalot

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    :confused: Richard isnt that excatly what I proposed two post earlier?



     
  11. Richard C

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    More or less so I agree with you; its also what I hinted at in my earlier post immediately before yours. ;)
     
  12. lancenotalot

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    OK Richard,I suppose as long as the op gets the best info thats all that matters really :D
     
  13. glock339

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    BUMP :)

    Dose anyone have any advise on the matter of piercing the DPM with the screws that would fix down the batten to the concrete? Would it be an issue?

    Cheers.
    Gary.
     
  14. Richard C

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    How do you know there is not already a DPM in the original concrete deck? If there really isn’t one, have you considered using a liquid DPM? The problem with a loose physical membrane over the deck is that it will be prone to condensation forming in the small air pockets below the membrane.
     
  15. glock339

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    No theres defo no DPM as there is a hole in it going rite down to the earth underneath in the corner where the water pipe comes in to look at. Also I'm sure the concrete deck in there was basically the back yard's ground originally and the bathroom was simply built onto it, the ground even sloped in 3 directions towards the yard gully outside before I leveled it.

    Great more problems I'm presuming a liquid DP will be a tad more expensive than a sheet of stuff that I already have in? Theres always summit! :LOL: What is the best stuff to use?
     

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