Shower trays (again)

[Dave]

I'm about to fit a B&Q quadrant resin/stone tray (once I take the warped one back and get a flat one - I assume the top should be flat(?)). My plan currently is to screw some 12mm marine ply to the new (green) chipboard in the new extension (the waste will drop down between the joists) and then bed the tray on 5:1 mortar on the ply.

Question: do I really need the 12mm marine ply if it's on green chipboard?

The default answer is "yes" but I'd rather avoid it because of difficulty making the edge look good - unless someone can suggest a neat way of trimming it around the quadrant...

[Brian G]

Dave,

When I fitted my resin shower tray. I levelled and fixed some 15mm ply to the T&G bathroom floor, bedded the tray, and then fitted some 75mm bevel edged skirting around it - screwed the bottom of it to the edge of the ply and "stuck" the top of it to the tray using No Nails adhesive. Been like that now for about five years - a good, trouble free solution to an odd problem (touch wood and all that :-) ).

Hope this is of use?

Brian G

[John Miller]

Dave

Not sure about the ply + green chipboard question, although if it's 18mm board with good support, I can't see why the ply is needed. The instructions I got with my own (Focus) shower-base a couple of years ago advise the use of green chipboard 18-20mm thick and make no mention of plywood.

I recently fitted a Wickes 800mm stone-resin quadrant base in my daughter's bathroom on a marine-ply platform. I loose laid the ply & base, marked it to suit then cut it with a jigsaw. Once fixed in position, got a length of deep uPVC trim with tapered edge from local plastics supplier (about 12 UKP for 5 metre length!) then cut that to length. The trim was quite thick and wouldn't bend to shape easily so I wedged it into corner bent into a tight "u" shape. After a couple of days, the trim had taken on a curved shape and I was able to secure it in place using silicone sealant. Not sure what your joist pattern is, but I also screwed a length of hardboard onto joist ends around the quadrant to give more surface area for the silicone to stick to (plywood and tray slightly proud of joists). This may not have been necessary. I hope all this makes sense!

My daughter was a demanding clerk-of-the-works but was very happy with the finished result.

John Miller

[John Miller]

Dave

Just reread your post and realised that you're not building a platform. Nevertheless, the uPVC trim idea should still work if you decide to use the plywood. You'll just need smaller, thinner trim strip which should bend into place quite easily.

John Miller

[John Rumm]

Bit tricky to bend round the quadrant I would have thought?

[Paul Barker]

Yes D profile from upvc window manufacturers is the stuff.

The single skin of woodchip floor isn't sufficiently durable, you d need to add another layer of same or better plye. Bed the plinth o silicon sealer.

Whenever I go to one of those houses built since woodchip floorin became the standard I curse. You have to make a right mess of the floo getting it up. Frequently it is shot, ruined by the slightest amount o water, turns to wheetabix.

I recently did my own buy to sell which I had to completely rebuild burned out carcass. I used t&g pine flooring throughout. I wouldn' even put woodchip in the mother in laws granny flat, I certainl wouldn't bed a shower tray on it.

YMM

-- Paul Barker

[Christian McArdle]

Personally, I wouldn't dream of using chipboard underneath a shower tray. I would probably use 18mm ply instead of 12mm. If I was worried by the step, I'd either cover the wood with some architrave, or cut out a square of chipboard and replace with similar thickness ply, ensuring that the join is over a joist and a noggin is laid.

No need for marine ply. WBP is good enough.

Christian.

[Dave]

Thanks for all the replies. The consensus seems to be to use the ply and that backs-up my own belief, because of the quadrant shape I don't really want to cut/route the existing floor so I'll just sit the ply on top and screw it down. I like the idea of the D section extrusion and will have a look through yellow pages for a supplier (unless someone can recommend anywhere in the Winchester-Southampton area???) Will it really curve enough to stay attached to a 550mm radius?

[Christian McArdle]

You don't have to cut the ply to the shape of the tray. Provided you choose a ply with the same thickness as the chip, you can go out further. The lino/tiling will cover the join. In fact, the curving nature of the tray would make me more inclined to go this route, as bending the moulding accurately might not be straightforward.

Christian.

[Dave]

Now why didn't I think of that! I must be working too hard. Thanks.

[Brian G]

Doh!

John you're correct. I mis-read the original post, and although the job is still possible with 75mm skirting - it is erm: a little more difficult to do.

At least my shower base is rectangular in shape and that WAS easy! :-)

Must keep off the Christmas supply of Jack Daniel's when I respond to these things.

Brian G

[Pete C]

Hi,

Another way would be to seal the chip with neat PVA or even better epoxy, especially the edges of any holes.

Bear in mind ply will rot in time if damp, unless it is treated or protected with something.

cheers, Pete.

[Simon Stroud]

Both my Matki "stone resin" trays are on 18mm ply. In both cases, I've cut it carefully to size using jigsaw (I guess a router would be much neater) and the edge is painted gloss white to match the tray. I've managed to slip in a bit of white silicone as well.

I've fitted Karndean flooring in both cases, and that sits on 6mm ply, which is itself cut round the same shape. So, the amount of 18mm ply edge sticking up above the finished floor surface isn't that much.

On the first one I fitted some PVC soft flexible bath sealant strip:

the second one I didn't bother:

'm happy with the result.

Regards, Simon.

[Simon Stroud]

Sorry, bad to reply to own post and all that.

Just to confirm, mine are both curved quadrant type trays. Sorry the pictures only show the back corners.

Regards, Simon.