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Shower tray movement

Discussion in 'Plumbing and Central Heating' started by ash1212002, 23 Dec 2019.

  1. ash1212002

    ash1212002

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    We've had a quadrant shower tray fitted, wasn't expecting it to be so light! purchased from Plumbworld

    The shower tray has been placed on a cement backer board which is on a suspended timber floor

    A mortar bed was laid down for the shower tray to adhere to, however 24 hours later I have noticed there is a slight up and down movement of the tray. There is no sideways movement.

    On closer inspection it appears some of the mortar has not bonded onto the shower tray.

    What has caused this to occur?

    The plumber has proposed to use expanding foam to ensure a secure bond which fill in any gaps

    Would this be the right approach?
     
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  3. denso13

    denso13

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    Perhaps mortar mix not wet enough or not the correct mix. Hard to tell but either way it hasn't worked.

    No, sounds like the plumber is looking for an easy fix but expanding foam isn't correct.
     
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  4. ash1212002

    ash1212002

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    Other than removing the tray and starting again, what would you suggest to secure the tray?
     
  5. oldbutnotdead

    oldbutnotdead

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    The mortar bed isn't securing the tray but providing firm support to it at all points. As others have said, possibly mortar bed was too dry-whatever, you'd be wise to take it out and do it again rather tham chancing it.
     
  6. denso13

    denso13

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    Nothing without removing the tray. You'll want it to last for many years to come and if it isn't done properly it will be on your mind every time you use it.
     
  7. Madrab

    Madrab

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    What make is the tray?

    I never use sand a cement anymore as I have found it's really unreliable and never seems to stand the test of time. That and it's real pig when it's time to change the tray.
     
  8. ash1212002

    ash1212002

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    It's a Podium Low Profile Quadrant Anti Slip Shower Tray - 1000x1000mm

    https://www.plumbworld.co.uk/podium...slip-shower-tray-1000mm-with-waste-68-1256755

    What would you use as an alternative to sand and cement?
     
  9. Madrab

    Madrab

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    Personally I'd use a silicone adhesive, it all comes down to what the underside of the tray is like though and what the contact patches are like. It also comes down to how level it is on the backer board.

    If it isn't steady then lift it and start again as it will never be right.
     
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  11. denso13

    denso13

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    Tile adhesive works well for me. The instructions mention contact adhesive but I don't know if I like the sound of that.
     
  12. Crezzer

    Crezzer

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    Adhesive foam would be better than expanding foam, but them light weight trays are crap.
     
  13. ash1212002

    ash1212002

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    Crap in what respect? This one was very light which I was surprised, Which one's are better the stone resin ones? Are they heavy?
     
  14. Crezzer

    Crezzer

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    The light weight ones dont last. Stone ones last a lot longer, yes they are heavy.
     
  15. Madrab

    Madrab

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    I have to admit that some of the new lightweight ones, as long as they are installed properly, will last plenty of time. Unfortunately though, IMO, loading it onto mortar isn't the best way, that's old school and isn't good enough these days.

    You need the tray flat and fixed down on all its moulded surfaces that touch the floor ergo the advice to use a silicone adhesive, that's one of the benefits of stone resin as they are usually flat based and sit nice and flat but that's all down to your installer. I certainly wouldn't be using foam of any type
     
  16. Steady

    Steady

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    For reference-Mira showers state in their manufacturers instructions that their Mira flight trays should be bedded down with either sand and cement or silicone sealant.
    but experience shows sometimes that neither of these are the proper solution.
    The design of the underside of these trays does not really lend itself to a sand and cement bed ,particularly when trying to lay in an alcove-If clearances are minimal all around the tray (as they should be)the sand and cement will squeeze up the sides and then makes trying to get the damn thing flat a real challenge.
    silicone will also bond in some cases very poorly to the subfloor-Have tried this on moisture resistant chipboard that was primed with SBR and even with a decent DOW silicone the bond was very poor-have had trays just lift out the day after without any difficulty as the silicone was simply not stuck to the timber subfloor.
    sometimes need to use an adhesive type sealant such as ‘plumbers gold’ instead of silicone.
    Interesting that the manufacturers blurb on the side of the tube actually states it can be used for bedding shower trays.Imagine you could use other grab adhesive’s instead but I would be cautious about using something with too high bond strength in case the damn thing ever needs to come out.
     
    Last edited: 26 Dec 2019
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  17. Madrab

    Madrab

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    My choice is a silicone adhesive (never a sealant), something like EVO serious stuff - wet grab/waterproof adhesive, or CT1 - either of those will stick to anything and cure to a nice strong silicone rubber bed.

    Never fix it to a bare sub floor (like floorboards/flooring etc), always use a backer board (as you have) either cement based or a WBP plywood. I will always tank a shower area now too, any of the liquid or cement based membrane types are pretty good these days (I use Mapei), ensures the best chance for longer term watertightness especially where stud wall/plasterboard is used and provides a perfect key for the adhesives above.
     
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