Shower tray bedding and trap fitting

[Kaymo]

I’ve got a shower tray to fit (Goodhome Linkski 800x800) and considering that the last shower tray I fitted was about 20 years ago, and was on an upstand so was relatively easy to do, I would really appreciate some advice!

First question is re the bedding of the tray. The previous shower tray was propped up on blocks of wood, probably fitted about 30 years ago and underneath is as dry as a bone. Its an attic bathroom and the flooring is chipboard, but its very thick and appears to be fairly solid. I’m planning on fitting 6mm backer board for the floor tiles (pro-warm xps type stuff) and wondering if it is ok to run this right under where the shower tray is going to go?

I understand that these type of trays are normally bedded and levelled, and I have seen everything from sand/cement, tile adhesive, silicone and expanding foam being suggested for this, and I am a bit overwhelmed by the lack of consensus. I’m also a bit concerned about the height if I have to add sand and cement whether this will bring it above the tile level, if its more than about 10mm. Any suggestions?

Finally, connecting the drain. I can access under the floor from the attic space behind the bathroom wall, but its going to be hard to screw on a trap from the angle, so I would prefer to fit the trap after the tray is fitted. I was thinking that with this type of Mcalpine trap I could push the unconnected 40mm pipe with the trap fitted, under the tray, then connect it from above with the tray installed, then finally terminate to the soil pipe. I’ve never fitted this type of trap before so wondered if this is possible?

Thanks.

 

[ktuludays]

Bed your tray on whatever the manufacturer says to use - most trays I install tend to be on a bed of mortar. I always fit the trap to the pipework and test before fitting the tray, this gives reassurance that it's leak free. The trap is then secured from above when the tray is fully fitted

Regarding the floor height I would bed the tray then overboard your floor around it and then tile. Generally with overboarding,adhesive and tile it comes above the height of the tray on a 10mm mortar bed.

 

[Deleted member 292770]

tile adhesive. mortar breaks down on timber.

 

[Wayners]

Skillbulder on youtube has all this covered so look it up.
Seems mistakes are still being made with tray fitting which they cover

 

[Kaymo]

tile adhesive. mortar breaks down on timber.

Skillbulder on youtube has all this covered so look it up.
Seems mistakes are still being made with tray fitting which they cover

I watched the skillbuilder episodes, and the guy on there said that tile adhesive is a bad idea, because he reckons that its too hard and any building movement results in cracked trays. He seemed to be in favour of the mortar bed. On the other hand, many people take Godwasaplasterer's view that mortar that thin would fall apart.

 

[ktuludays]

Most manufacturers state a bed of mortar. I've fitted loads as per their instructions and had no tray issues at all.

 

[Kaymo]

Bed your tray on whatever the manufacturer says to use - most trays I install tend to be on a bed of mortar. I always fit the trap to the pipework and test before fitting the tray, this gives reassurance that it's leak free. The trap is then secured from above when the tray is fully fitted

Regarding the floor height I would bed the tray then overboard your floor around it and then tile. Generally with overboarding,adhesive and tile it comes above the height of the tray on a 10mm mortar bed.

Thanks for the reassurance on the fitting of the trap first. Logically it seemed like that would work, but its good to have it confirmed by someone who has done it before.

The problem here is that the manufacturer doesn't say anything about how to bed it. The tray is being delivered next week, but I spoke to someone who already had it and said that there was nothing in the instructions about bedding and no helpline (b and q tray). The tray can go on legs or flat on the floor, but no instructions as to how to fix or bed to the floor.

 

[Kaymo]

Most manufacturers state a bed of mortar. I've fitted loads as per their instructions and had no tray issues at all.

Thanks. I was leaning towards the mortar, the skillbuilder guy made a good case for it, although tile adhesive obviously works for a lot of people. I don't have cement handy, but I have a NHL3 and sharp sand, which presumably will do the job, might be better even with the small amount of flex that lime mortar allows for.

 

[Baths'N'Gas]

Rapid set floor tile adhesive rather than a mortar mix

 

[Kaymo]

Whether I use mortar or tile adhesive, am I ok to put this straight on to the chipboard flooring, or better to run the xps backerboard under the shower tray area as I mentioned in the OP?

 

[Deleted member 292770]

Sorry, should have said ‘flexible’ tile adhesive.
cement on chipboard. never.

 

[Kaymo]

Sorry, should have said ‘flexible’ tile adhesive.
cement on chipboard. never.

So flexible tile adhesive would be ok straight to chipboard?

If not I think the skillsbuilder guy on youtube was suggesting putting a plastic sheet between the tray and the tile adhesive, so I suppose the same thing could be done between he chipboard and tray.

 

[Deleted member 292770]

.

 

[Baths'N'Gas]

I screw to the floorboards or chipboard either backer boards or 9 or 12mm ply depending on the floor and position on the joists, then flexible floor tile adhesive to stick the tray down

 

[Madrab]

Just to throw it in the mix (no pun intended ), personally I haven't use sand and cement/tile adhesive for years now. More and more manufacturers are stepping away from solely sand a cement/adhesive approaches to bed their trays down with, especially with higher end stone resin trays.

That being said, it the MI states it must be installed using sand a cement and the warranty is to be retained then that's what needs to be used. Even using tile adhesive will invalidate the warranty.

Fitted a Mira Flight tray about a month ago and their MI now suggests both options, sand and cement or silicone to bed the tray down with. Did a Villeroy and Boch tray late last year and their MI suggested a sand & cement mix, a silicone adhesive or expanding foam to bed their trays down with. Go figure.

Ultimately the key with any tray is a solid, flat base (ply or OSB3 with me) and check the tray base isn't beveled before fitting and if you want to honour the warranty then follow what the MI wants, even then though most Man find other ways to invalidate their warranties.