Fitting stone shower tray on floor (two plumbers says no cement required?)

[dilalio]

This is what I thought.

Plenty of pva first

 

[undertrained]

Plenty of pva first

Is this like when used for sealing a porous surface?

 

[glen8]

So what am I doing

 

[dilalio]

Is this like when used for sealing a porous surface?

Yup. Stops the background sucking all the moisture out of coatings.

 

[dilalio]

So what am I doing

If it's dead flat and the manufacturers approve silicone then use it.

But if the edges of the tray protrude past the base of the tray, you'll need something with more substance to fill the void.

 

[glen8]

Thanks

Would this be ok for the walls? (and maybe the floor)

https://www.amazon.co.uk/Everbuild-...AH6WE55NZY7&psc=1&refRID=C8CWJMK8MAH6WE55NZY7

 

[Madrab]

What's your favoured method @Madrab?

I have to admit, I will always try to put a tray on a plinth with an 18mm WBP ply top, unless I'm sinking it into the floor. I find it allows for easier access to the waste for any servicing later, stays stable against the wall over a longer time and is easier to level.

I then use a scrim backed rubberised jointing tape to do the wall to floor/plinth edges, the corners and any joints in the walls. If the walls aren't square then use a tray seal or alternatively I sometimes use Sealux Shower Seals depending on the gap sizes

I have to admit though that after using many different cement polymer or synthetic based tanking membranes (BAL/Kingfisher/Permagard etc) one of the easiest to use just for a normal sized shower wet area, without any failures so far, is Mapei's tanking kit.

If it's a wet room or floor former on wood then I find the key is to avoid/absorb as much movement as possible as a wooden substrate will always flex and expand, as that is any waterproofing's Achilles heel, I'd then use cement backer board on the walls, the floor is covered with a thick WBP ply and then lined as @dilalio mentions with a good quality waterproof lining material and then use a cement based polymer to give a flexible tough longterm waterproof seal where it all joins together.

 

[jammmy]

My plumber used some sort of grab adhesive to bed in the tray. It hasn't been a problem but as the floor wasn't level and it is only a thin layer, the tray ended up a bit sloped. Made fitting the enclosure trickier than it should have been for me.

Are you going to use a mixer bar? If so is there going to be anything supporting its weight?

 

[dilalio]

I have to admit, I will always try to put a tray on a plinth with an 18mm WBP ply top, unless I'm sinking it into the floor. I find it allows for easier access to the waste for any servicing later, stays stable against the wall over a longer time and is easier to level.

I then use a scrim backed rubberised jointing tape to do the wall to floor/plinth edges, the corners and any joints in the walls. If the walls aren't square then use a tray seal or alternatively I sometimes use Sealux Shower Seals depending on the gap sizes

I have to admit though that after using many different cement polymer or synthetic based tanking membranes (BAL/Kingfisher/Permagard etc) one of the easiest to use just for a normal sized shower wet area, without any failures so far, is Mapei's tanking kit.

If it's a wet room or floor former on wood then I find the key is to avoid/absorb as much movement as possible as a wooden substrate will always flex and expand, as that is any waterproofing's Achilles heel, I'd then use cement backer board on the walls, the floor is covered with a thick WBP ply and then lined as @dilalio mentions with a good quality waterproof lining material and then use a cement based polymer to give a flexible tough longterm waterproof seal where it all joins together.

Most of my customers want a low profile or level access tray which means getting everything into the floor so a good quality high volume trap is essential.

Do you silicone your trays down? I've done a few on flat ply floors that way, when (as I said) the whole of the tray bottom is level and the slopes moulded within the thickness of the base, but a lot of my customers have read about cement base and when that's what the MI's state, I'm reluctant to argue

 

[glen8]

My plumber used some sort of grab adhesive to bed in the tray. It hasn't been a problem but as the floor wasn't level and it is only a thin layer, the tray ended up a bit sloped. Made fitting the enclosure trickier than it should have been for me.

Are you going to use a mixer bar? If so is there going to be anything supporting its weight?

The grohe one I have can only be held by the fixings to the pipes.

 

[Madrab]

Do you silicone your trays down? I've done a few on flat ply floors that way, when (as I said) the whole of the tray bottom is level and the slopes moulded within the thickness of the base, but a lot of my customers have read about cement base and when that's what the MI's state, I'm reluctant to argue

Yeah ... I feel your pain ... luckily I've always managed to talk my customers round from using a cement bedding no matter what the MI states. I just tell them that the manufacturers aren't here, it's legacy thing prior to the new adhesive being made available and they don't have to lift a badly laid cement base prior to fitting any new tray or bath in the future. Nor do they have a nice flat & well prepared surface to sit the tray on.

I'll mainly use a waterproof silicone adhesive (Evo Wet Grab etc)to bed the tray down. I always use a spirit to clean the bottom of the tray and whatever surface it's to sit onto and mate to, prior to bedding down to ensure a good grab. That coupled with a good antibacterial silicone (DC usually) for all the wall edges that the tray will sit against. One seal along the bottom edge, full seal on each edge that touches a wall, sit and press into place and then a top up along any top edge gaps and then flatten getting rid of any air bubbles and then let it set, allows any areas that slump to be topped up prior to any wall covering going on and then another seal along that.

 

[Madrab]

I only ever use a fixing kit to fit bar mixers now. Then it's either a good ply backed wet board (never that cheap 3mm honeycombed crap)and it's screwed onto it or talk to the tiler to ensure the holes in the tiles are cut tight to the pipe (18mm max) and that the tile is well covered in adhesive behind it to support drilling the mounting holes.

 

[glen8]

I only ever use a fixing kit to fit bar mixers now. Then it's either a good ply backed wet board (never that cheap 3mm honeycombed crap)and it's screwed onto it or talk to the tiler to ensure the holes in the tiles are cut tight to the pipe (18mm max) and that the tile is well covered in adhesive behind it to support drilling the mounting holes.

It's this one

https://www.amazon.co.uk/gp/product/B00EXSML0C/ref=ppx_yo_dt_b_asin_title_o02_s00?ie=UTF8&psc=1

 

[jammmy]

To take the weight of the bar you would use something like this at the end of the pipe (instead of the elbow you have now) screwed to a horizontal support. The offset brass thing (technical term) supplied with your shower would screw into this.

https://www.screwfix.com/p/compression-adapting-90-wall-plate-elbow-15mm-x/92934

Or as Madrab says something like this, that your shower should screw straight into.

https://www.screwfix.com/p/bristan-bar-valve-wall-mount-11-fixing-kit-chrome-plated/58495

Might also be a good time to add any wooden support where the screws for the shower enclosure would go.

 

[glen8]

To take the weight of the bar you would use something like this at the end of the pipe (instead of the elbow you have now) screwed to a horizontal support. The offset brass thing (technical term) supplied with your shower wood screw into this.

https://www.screwfix.com/p/compression-adapting-90-wall-plate-elbow-15mm-x/92934

Or as Madrab says something like this, that your shower should screw straight into.

https://www.screwfix.com/p/bristan-bar-valve-wall-mount-11-fixing-kit-chrome-plated/58495

Might also be a good time to add any wooden support where the screws for the shower enclosure wood go.

Good tip!

The distance between the pipes in the wall is 165mm. That's what the builders did. Watching a plumbing YouTube channel assume I bring the outlet close to the hole then after tiling use the adapter to decrease to 150mm