what lies beneath

Discussion in 'Tilers' Talk' started by robbieg, Mar 18, 2018.

  1. robbieg

    robbieg New Member

    so im converting a bedroom to a bathroom and as part of that im taking up the floor boards what would be the best subfloor to lay before tiling bearing in mind i want to keep the floor as thin as possible to avoid as much as possible aheight change between hall and bathroom if ply then tile backer is best then what thicknesses or is there an all in one product? i could relay the floor boards if needed but that seems crazy oh and we will have a cast iron bath in there
    thanks rob
  2. DIYDave.

    DIYDave. Screwfix Select

    Take a look online at Hardie Floor

    Floorboards are removed, lay down Hardie Floor (following instructions), ready to tile onto - job done

    Several thicknesses available, can’t advise on what to use, I’m sure others can though

    Will depend on several factors -
    How much spring is in current floor joists / weight of tiles being used / and yeah .... that heavy old cast iron bath !

    Anyway, start reading up on the product, more advise will follow :)
  3. robbieg

    robbieg New Member

    hi when i looked at hardie boards they were still laid onto ply not sure how thick maybe 15 or 18mm
  4. Jord86

    Jord86 Screwfix Select

    If you're planning on a cast iron bath then I would look at reinforcing your joists while you have the opportunity to do so.
  5. DIYDave.

    DIYDave. Screwfix Select

    Take a look at online fitting instructions

    Not used them myself admittedly but clearly shows boards being laid directly onto joists, with adhesive and screws

    Can’t comment on thickness to use
    As above, beef up joists for bath area, maybe shower if ur fitting one as well

    Any flex in floor will lead to tile / adhesive / grout / failure over time
  6. Jord86

    Jord86 Screwfix Select

    Thickness to use depends on how far apart your joists are I.e. 400 or 600 centres/ 16" or 2', I'm not experienced with Hardibacker but I would never opt for any floor covering under 18mm thick.
  7. CGN

    CGN Screwfix Select

    Hardiefloor is a structural floor board replacement, hardiebacker is for overlaying existing floor boarding (use 6mm), or 12mm on walls.
  8. Pollowick

    Pollowick Screwfix Select

    Hardie FLOOR is definitely direct onto joists. 19 or 22 thick. If your joists are 600 centres then you need 22mm. the boards are 2400 long and 500 wide with a T&G system. Once laid, you can tile direct onto it - however, if there is a wet room/shower then tanking is advised.

    There is also an acoustic version which is 27mm thick - but you can achieve the same by putting insulation between joists.

    https://www.jameshardie.co.uk/import/Documents/HardieFloor Brochure.pdf
  9. robbieg

    robbieg New Member

    ok thanks ill look at the hardie floor
  10. goldenboy

    goldenboy Super Member

    cast iron.jpg

    100%. Huge weight in a cast iron bath full of water This took 4 of us to carry it up the stairs. Spent a long time on this job. Room was stripped back completely and all the panelling done to match existing bathrooms.
  11. Pollowick

    Pollowick Screwfix Select

    It does need to be considered but is not as bad as it initially appears. Check the weight of te bath and typical volume it holds.

    An acrylic bath weights maybe 25 to 50 kg. there could be 225litres (50 gall) of water which would be another 225 kg plus a person of maybe 80 to 100kg - so at worst case 375 kg. And maybe more if you "share the bath" or have it really deep.

    A cast iron bath is 125 kg (could be more or less depending on style and age), so when filled and with one person in the total may be around 450 kg or 20% more than before.
  12. Jord86

    Jord86 Screwfix Select

    Only once I've been unfortunate enough to carry one, up two flights of stairs :confused: that also took four of us and our knackers were down to our knees by the time we manoeuvred it into the bathroom. Made even more difficult by the lack of handholds to grip firmly. Never again, says I! :rolleyes:
  13. goldenboy

    goldenboy Super Member

    There were four of us dragging it up.

    It was a lot lot heavier that two and a half old school bags of cement.

    My guess somewhere between 250 and 300kg.

    It was a specially made one though.
  14. CGN

    CGN Screwfix Select

    Have had to break a couple up on jobs over the last few years.

    Shame as one was a really nice bath, but was the heaviest one to date and I wasn't going to risk injury or damage to the property just to get it out in one piece.

    Was an old boy and it came the time to break it up so gave him the heads up and got busy with a sledge hammer. Almost felt like putting down a family pet :(
  15. Dr Bodgit

    Dr Bodgit Super Member

    I broke up my old cast iron bath into 4 pieces, each of those was quite heavy albeit manageable. Had to cope with very sharp edges too. Left it outside and just as I hoped, the pikeys took it away. Same with the cast iron stack!
    CGN likes this.

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