Going to lay a shower former at posi joist level, i have put 2x4 supports beneath for a material to sit on. What would  the best/strongest way to make the height up for former to sit on?

Regards  James

A quick picture may help to advise.

Regards. James

Sheet it with OSB3. 2x 18mm + 1x 11mm. 

Thanks for the reply, so no need to use waterproof ply? Will the former adhere to OSB  and what would you recommend for that, think I’m going to be using a jackoboard former.

Regards. James

37 minutes ago, James94 said:

Thanks for the reply, so no need to use waterproof ply? Will the former adhere to OSB  and what would you recommend for that, think I’m going to be using a jackoboard former.

Regards. James

You can change the 11mm OSB and top the 18’s with a 6mm aqua board / cement panel. Then 5mm of tile adhesive to set the tray in nicely. 

Use the correct corrosion proof screws for the cement board !

@Nickfromwales

Thanks for the help, I’ve got a tiler coming to look Monday and I let him know what I plan to do ready for him tiling. It’s still a while away just trying to get first fix plumbing done so we can. Get plastered out.

Regards. James

I had settled for a jackoboard 1600x900 x30mm linear former but this only comes with the drain in a central position which will not work as I have a joist in centre of each of the openings.

I have done a bit of searching and come across this one, has anyone on here had any experience with this model/design, or can recommend one with a flexible outlet position.

https://wetroomstop.com/linear-wet-room-kits/wetroomstop-shower-base-900mm-x-1600mm-x-30mm-with-600mm-end-linear-drain.html#/1-tanking_kit-pci_lastogum_3_m/16-drain_cover-reversible/21-waste_trap-dallmer_fast_flow

 

Regards. James

 

@Nickfromwales so we’ve got 2 x 18mm layers of osb 3, then a cement board then the wet room former bedded onto that.

 

do I need to adhere the cement board or just screw to the osb? And what adhesive would you recommend for adhering the tray to the cement board?

 

james

flexible cement based tile adhesive for sticking cement boards down, or whatever the manufacturer recommends.

Use adhesive for all layers above the OSB. The cement board should be set into adhesive and tapped down to the desired height, making it level and flat. The tray can then be bonded down as per the MI’s. If using tile adhesive to bed the tray, use some of the mix to decontaminate the underside of the tray by scouring it with the mix on a cotton cloth.