shower tray

Discussion in 'Tilers' Talk' started by SrewcFix, Jun 14, 2010.

  1. SrewcFix

    SrewcFix New Member

    Just got a shower tray it suggests setting on a 5/1 cement mix, have had experience of this just crumbling away in the past, someone suggested putting on tile adhesive anyone any experience of this, or any other suggestions.
  2. tic tic

    tic tic New Member

    follow m.i. for bedding in,sounds like you have not made the mix correctly before,(or the timber subtrate had to much flex in it)..and yes you can bed it in with a flexiable floor addy.(again depends on the subtrate,timber how much flex in it?).
  3. tango waggon

    tango waggon New Member

    Iv'e never comprehended the sense in using sand & cement for this job! perhaps ok on a concrete floor but on any type of timber, the moisture from the mix will expand the surrounding timbers which will take months to fully dry out again, shrinking and cracking the seal around the tray.
    Having ensured the floor is as solid as possible, I lay the tray in position and check for level on each side and diagonals, I use plastic glazing packers placed under the tray to get it level.
    Once the tray is level and the waste is accessible to fit, I lay strips of expanding foam about 4" apart on the floor across the tray area, this is the skill bit too much foam may lift the tray and too little won't give adequate support, always use fresh foam, old foam that has lost its propellant can cause problems.
    Don't create any closed areas in the foam, strips mean the air between the strips can escape as the foam expands.
    Lay the tray in place and place tubs of tile adhesive, tiles or anything else heavy on the tray. leave acouple of hours to set,
    Thouroughly clean and vacuum the gap between the tray and the walls and fill it with silicon sealant. Use a rubber grout float to smear the excess silicon up the wall, I usually end up with about 20-50mm smeared up the wall, this effectively acts as an upstand behind the tiles, I also smear some up the corner anbout 150mm, ideally, leave this to set.
    Next I fit one of the plain L shaped bath seals (Genesis do one) over the silicon, held in place with more silicon. then tile as normal, leaving about a 3mm gap between the bottom tile and the seal. I always run a length of fiberglass plasterers scrim up the corner to help resist any cracking. If any silicon squeezes out from under the seal, leave it a couple of hours so it has set but not bonded to the tray and run your fingernails or a piece of plastic back and forth to remove it.
    From this point, even the corner joint is grouted such that NO silicon is on show or exposed to go mouldy in the shower itself.

    So far, in 10 years of fitting bathrooms, no- one has called me back to fix leaky showers.
  4. Guest

    As tic tic says you should follow the MI's instructions.

    Although in my experience I think mortar tends to slide about a bit when your positioning the tray, that's something that has always concerned me, it's quite difficult if your stuck in a tight opening to lower a stone tray properly, unless your popeye.

    tango, you obviously know what your doing and well done, but your system would never be adopted, because it's not idiot proof.

    next time 'paragraphs' please.
  5. tango waggon

    tango waggon New Member

    Forgot to say that grouting is critical, buy yourself a proper rubber grouting float and really force the grout into the joints and top them up once the grout has shrunk a bit before tooling off, I've tried many grout tools but the best I've found so far is a 150mm length of 10mm speedfit plastic pipe!. don't touch readymixed grout horrible stuff.
    Nothing is ever idiot proof, they'd just invent a better idiot!
  6. blueassedfly!

    blueassedfly! New Member

    after all that tango, when the tray says only use mortar to bed the tray i just add a touch of retarder to the mix so it doesnt dry oout to fast on the timber that ive primed before fitting, never had a tray move or leak either!
  7. tic tic

    tic tic New Member

    Re: shower tray
    Posted: Jul 3, 2010 8:58 AM Reply

    Forgot to say that grouting is critical, buy yourself a proper rubber grouting float and really force the grout into the joints and top them up once the grout has shrunk a bit before tooling off, I've tried many grout tools but the best I've found so far is a 150mm length of 10mm speedfit plastic pipe!. don't touch readymixed grout horrible stuff.
    Nothing is ever idiot proof, they'd just invent a better idiot!

    tooling aff grout........:^O :^O
    heard it all now..a good squeegy and a good sponge and thats it!!!

    let the grout set for 15-20min..then wipe with a semi wet sponge across tiles,this way the grout will be level with the tiles...and not below tile level(tooling off)...
    if ma auld tradesman heard me saying or doing that

    ...tooling aff grout......i would have 3 adams apples..:^O:^O
  8. tango waggon

    tango waggon New Member

    Tooling off thoroughly consolidates the grout and makes the surface harder and more resistant to mould and water penetration, it also shows up any areas that aren't quite filled.
    There's those that know
  9. Captain Leaky

    Captain Leaky New Member

    Fitted trays on mortar for years and never tooled off the grout - I have never had problems with either!

    The bottom line is always follow the MI's if you want any warranties to be honoured.
  10. ian anderson

    ian anderson New Member

    Seen plumbers pinch plasterboard adhesive to bed trays!

    Never seen anyone tool grout tho........
  11. Jerryd

    Jerryd New Member

    Just fitted a very long tray (1700 x 700).
    After a lot of chin rubbing I went with expanding foam like tango waggon.
    The timber floor was out of level by around 10mm (highest to lowest corner).
    I started by putting some timber packs in three of the corners so the tray sat level.
    I then put foam on the floor in strips and carefully lowered the tray into place (and prayed I hadn't overdone the foam).
    I actually used some expanding foam designed for fixing plasterboard.
    Time will tell but the tray seems nice and level and feels solid.
    Fingers well and truly crossed.
  12. DIY0001

    DIY0001 Member

    Prime the timbers before putting on the mortar mix! It might be called "marine ply" but that only means it has no voids within it. All faces and edges need to be sealed before coming into contact with water, or the moisture of a mortar mix. There is moisture in tile adhesive as well, so that won't avoid timber expansion and contraction problem either. Priming, or otherwise sealing, the timber is what does that.

    Before starting to lay the tray, screw a length of timber batten into the floor about 1cm out from where the front edge of where the tray will go. Lay the mortar base on the primed marine ply base and level out. Check the mortar level in all directions.

    Tie a couple of lengths of webbing around the tray to form two loose loops without any twists in them, with the knots on the top side of the tray. Lift the tray using the webbing loops, one in each hand, into a vertical position and place the near edge of the tray on top of the batten, with the bottom of the tray just over the rear edge of the batten. Push the back edge of the tray (now at the top) slightly forward and take up the strain in the webbing. Then slowly allow the tray to rotate evenly into the horizontal position by letting the webbing slowly slip through your grip. The knots in the webbing loops can help control the rotation of the tray. Once the tray has rotated flat onto the mortar base, cut the webbing loops and pull the strips out from under the tray. Check the tray level and place some weight evenly on the tray to ensure it stays in contact with the mortar as it sets. If the tray is slightly out of level then place weights, such as a bag of sand, on the higher part and "wiggle" the tray back and forward on the mortar until it levels up. Leave to set overnight and then remove the batten from the floor.

    You can place a tray in the tightest of spaces using that method and it retains the manufacturer's installation warranty. Using tile adhesive or expanding foam as a support base is unlikely to meet the manufacturer's installation warranty, no matter how "solid" it initially seems.
  13. Mr Rusty

    Mr Rusty Well-Known Member

    With all this foam used,, makes you wonder if in 50 years some chemical change will turn it all to dust...My house will be in trouble if it does, but I doubt I'll be around.

    Never heard of shower trays on foam before, but can't really think of any reason why not, other than it might be a struggle to claim against a manuf warranty.

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