Shower Tray Plinth and Joists.

[Dav657]

Hi, I have a Mira Flight 1500 x 700mm shower tray which I am installing on a wooden plinth topped with 18mm Ply.
The tray will run length ways along the top of the floor joists of which it will span only two. One right at the side along the wall and another one 15 inches (approximately 40cm) parallel to it. One side of the tray and plinth overhangs this by roughly a foot (30cm). The floor is covered in moisture resistant chipboard and the plinth will sit on top of it.
My query is the weight of the tray, plinth and of course the person in the shower, will the joists bear the weight.
The room is 2 metre x 2 metre and both end of the joists are in th solid walls.

 

[blup]

Should do as the ply will spread the weight. I would put in an additional joist to support the ply (avoiding the waste) so the plinth isn’t t left bearing all the weight at the edges

 

[Madrab]

The joists should bear the weight no bother, will the P5 floor deflect at the spot in between the joists , it might given the long edge of the plinth will be sitting in the void between the joists. Can you open that section of the floor and drop in a couple of dwangs, just to span the gap and support the floor and plinth above it?

 

[Dav657]

Yes, I've added three noggins to bridge the gap, plus I'm building the structure on a sheet of 18mm Ply and toppin it with the same. The bottom sheet will be screwed to the two joists.

 

[foxhole]

I used cement board on mine, more stable.

 

[Madrab]

Yes, I've added three noggins to bridge the gap, plus I'm building the structure on a sheet of 18mm Ply and toppin it with the same. The bottom sheet will be screwed to the two joists.

Should be more than enough then. Just ensure the plinth is well framed internally and try and square around where the waste will be, with an open end for the waste pipe, if you know what I mean.

 

[Dav657]

Yes, thanks very much, really appreciate your input.