Are Shower Tray Toleranced to be Undersized?

[MortarThePoint]

I'm building the partitions of a bathroom and it's 1200mm wide for a 1200mm x 800mm shower tray. I'll be tiling onto the top of the tray (as shown below), but if I make the room 1200mm will the shower tray definitely fit or is there a tolerance that could catch me out. I'm hoping the tolerance is +0 / -Xmm so not allowed to be oversized, but hope isn't good enough. Does anyone know. I can easily wiggle an extra 3mm out of the plasterbard (1.5mm gap at each end) but wouldn't want to go much further.

 

 

[PeterW]

30 minutes ago, MortarThePoint said:

I can easily wiggle an extra 3mm out of the plasterbard (1.5mm gap at each end) but wouldn't want to go much further.

 Plasterboard or cement board ..? The latter is a pig to adjust. Tray will be about 2-4mm different in size - usually less than dimensions quoted. 

[MortarThePoint]

25 minutes ago, PeterW said:

 Plasterboard or cement board ..? The latter is a pig to adjust. Tray will be about 2-4mm different in size - usually less than dimensions quoted. 

12.5mm Plasterboard over 11mm OSB

[PeterW]

Moisture proof board I am assuming ..? And why OSB and PB when a single skin of cement board would be quicker and cheaper ..?

[SuperPav]

I wouldn't put PB in a shower enclosure personally when you can use cement board or marmoxboard.

 

Another thing to bear in mind in terms of the width is the tiles you're planning on using. If you're using 300 or 600 tiles, don't make the back wall less than 1205-1210mm (tile that one first before the sides) as otherwise you'll need to be shaving off a couple of mm off every other course of tile to fit between the walls!

[MortarThePoint]

28 minutes ago, PeterW said:

Moisture proof board I am assuming ..? And why OSB and PB when a single skin of cement board would be quicker and cheaper ..?

 

Yes moisture resistant plasterboard. I have the materials on site so that saves time.

[MortarThePoint]

23 minutes ago, SuperPav said:

I wouldn't put PB in a shower enclosure personally when you can use cement board or marmoxboard.

 

Another thing to bear in mind in terms of the width is the tiles you're planning on using. If you're using 300 or 600 tiles, don't make the back wall less than 1205-1210mm (tile that one first before the sides) as otherwise you'll need to be shaving off a couple of mm off every other course of tile to fit between the walls!

 

I'm avoiding Hardie Backer and the like. Also I'd tank the moisture resistant plasterboard

[wozza]

Can you not fit the tray before building the wall?

[MortarThePoint]

17 minutes ago, wozza said:

Can you not fit the tray before building the wall?

 

I haven't got the tray yet and it could get trashed if I did

[Conor]

Get the tray. Ours was nearly 10mm longer and wider than stated.

[MortarThePoint]

31 minutes ago, Conor said:

Get the tray. Ours was nearly 10mm longer and wider than stated.

That was my fear. Is there anywhere you can think of with shower trays on the shelf? Would be good to unblock progress

[PeterW]

2 hours ago, MortarThePoint said:

 

I'm avoiding Hardie Backer and the like. Also I'd tank the moisture resistant plasterboard

why..?? You only need to do the joints on cement board, with your approach you have 3 layers, 3 times the Labour ..? 
 

6 minutes ago, MortarThePoint said:

That was my fear. Is there anywhere you can think of with shower trays on the shelf? Would be good to unblock progress

 

what size ..? And depth ..? Any particular style ..? 

[Conor]

34 minutes ago, MortarThePoint said:

That was my fear. Is there anywhere you can think of with shower trays on the shelf? Would be good to unblock progress

Or, you can just do what I did and trim the plasterboard away!  My tray has a good 40mm wide shoulder so no issues with a bit of a thicker build up over it. I'd advise against having anything fragile on site longer than needed. I caught the sparks sitting on the shower screen box 🤬

Edited May 28, 2022 by Conor

[MortarThePoint]

37 minutes ago, PeterW said:

what size ..? And depth ..? Any particular style ..? 

 

1200mm x 800mm reasonably low. Not too fussy about style but needs yo be white or very light grey, but the waste needs to be in the middle of the short end or in the corner shown below.

 

Something like : https://www.screwfix.com/p/mira-flight-low-rectangular-shower-tray-white-1200-x-800-x-40mm/1906x

 

Edited May 28, 2022 by MortarThePoint

[PeterW]

Toolstation do them on 3 day delivery as do Victoria Plum. When do you need it ..?

[MortarThePoint]

22 minutes ago, PeterW said:

Toolstation do them on 3 day delivery as do Victoria Plum. When do you need it ..?

 

It was my plan to get the walls up this weekend 🙂

Change of plan time

[MortarThePoint]

On 28/05/2022 at 13:51, Conor said:

Get the tray. Ours was nearly 10mm longer and wider than stated.

 

Just went to City plumbing and they said would be spot on but was slightly over 1210mm. That was the with up stand type (see pic below), which may be slightly larger. The guys in the store were genuinely surprised when they saw what I measured. This was a 4 sided up stand Mira Flight 1200mm x 800mm.

 

Edited May 30, 2022 by MortarThePoint

[MortarThePoint]

Attached are the dimensions sheets that Mira emailed me, converted to images

 

 

[Temp]

Our builder was a stickler for checking stuff like this. Never drilled, cut, ordered or built anything until he had actual thing that was going to fit in it. So things like windows weren't ordered until he built all the openings. Said he was fed up getting caught out.

[MortarThePoint]

1 hour ago, Temp said:

Our builder was a stickler for checking stuff like this. Never drilled, cut, ordered or built anything until he had actual thing that was going to fit in it. So things like windows weren't ordered until he built all the openings. Said he was fed up getting caught out.

 

I can understand that. Murders the timeline though