Raising shower tray

[Barnboy]

Hi all,

 

I have a Merlyn level 25 shower tray to install in our ensuite. 

The floor is currently 2mm waterproof Caberdeck which I'm looking at adding a 6mm Jackoboard followed by ufh mat, 5mm self levelling, adhesive and tiles which above the Caberdeck will give me about 26/28mm build up.

My 2 questions are,

Do I lay a thin bed of adhesive and screw down the Jackoboard, or just screw it down ?

The shower tray is only about 26mm high so this will need to come up to not risk it being below the tiles.

I'm planning on bedding it onto some tile adhesive rather than csand and cement as this seems the recommendation in other posts, do I use the thickness of the adhesive to gain me an extra 5 or 6 mm in height or do I continue the Jackoboard across the whole floor and then bed the tray onto adhesive ontop of the Jackoboard ?

Thanks

[Barnboy]

Ok, no answers but another question,

Tile adhesive onto 22mm waterproof Caberdek, the grey smooth shiny stuff.

Will adhesive adhere straight to this or do I need to treat it with SBR or similar?

It's designed for bathroom floors so I'd hope it would be OK to go straight on but I rather do the job properly once.

 

Thanks

 

[crispy_wafer]

51 minutes ago, Barnboy said:

Ok, no answers but another question,

Tile adhesive onto 22mm waterproof Caberdek, the grey smooth shiny stuff.

Will adhesive adhere straight to this or do I need to treat it with SBR or similar?

It's designed for bathroom floors so I'd hope it would be OK to go straight on but I rather do the job properly once.

 

Thanks

 

 

I'd prime the boards first, you'd lose nothing by doing so.  Something suitable and not water soluble.

 

and for the jackoboards

 

 

[Barnboy]

Thanks @crispy_wafer I'd seen this but my worry is that the adhesive won't take to the smooth shiny finish of the waterproof caberdek. I'm going to try priming the floor with some Thistle bond,  a friend told me today that he used it when he bedded his tray down on a sand and cement bed after it didn't bond to the same flooring.

[Omnibuswoman]

Helpful for me as I am at the exact same point - caberdeck 22mm flooring, shower tray and floor tiles going down in the next few weeks. I have been wondering whether or not to lay something on the caberdeck prior to laying the tile adhesive for the shower tray...

[Barnboy]

@Omnibuswoman hopefully it works, I've just rollered it on, it's odd stuff, quite thin but with a grit in it which will give the adhesive something to adhere to. The tub says to allow it to dry for at least 24hrs  so that gives me a bit more time to pluck the courage up to fit the tray.

[Marvin]

Hi @Barnboy

 

The answer in my experience depends...

Any timber surface should be sealed. I use Acrylic primer. 

Jackoboard is a tile backer board and I think there is different types for different uses (i.e. walls or floor) and is waterproof and suitable for tile adhesive. 

 

 https://www.jackon-insulation.com/downloads-service/download/jackoboard-plano-floor

 

I would stick the shower tray down with a layer of waterproof tile adhesive (ok, showerproof adhesive) no more than 5mm thick is best: 

 

I silicone the gap between the side of a shower tray and the walls by levelling the tray on the tile adhesive and the sliding the tray about 5mm away from the walls, run a line of quality silicone sealant and squeeze the tray back the the final position cleaning the excess off. Check the levelness. I usually add weight to the tray by placing boxes of tiles carefully on the tray, checking the door threshold is level (some trays are not flat and so you need to do the best to keep the tray level under where the enclosure is going to go.) 

 

[Marvin]

16 hours ago, Barnboy said:

Thanks @crispy_wafer I'd seen this but my worry is that the adhesive won't take to the smooth shiny finish of the waterproof caberdek. I'm going to try priming the floor with some Thistle bond,  a friend told me today that he used it when he bedded his tray down on a sand and cement bed after it didn't bond to the same flooring.

I would never use sand and cement. a 5mm layer will crack like a biscuit as the floor below flexes.