Flush or raised shower tray on concrete floor?

[Roger465]

One or two of you have been kind enough to help me on my previous thread, which concerned how to remove tiles intact from an old, crumbling shower cubicle etc. As I’m retired now, I’m lucky enough to have lots of time on my hands, and also have another shower, so can take a loooong time doing things, which of course wouldn't be economical for a builder or plumber.

So I’m working very slowly, asking lots of questions, doing as much as I can before getting a professional in. I’ve managed to remove the existing tiles – which I want to preserve – mostly intact, and am busy soaking them for days, then hacking the adhesive off the back to re-use them (I’m doing this because the entire en-suite is tiled with the same obsolete tiles, and I don’t want to do the whole place).

I’ve put new studding in, installed backer board etc, and am now ready to get a new shower tray in (the old one was made of something like mortar, and was cracked and leaking). So here’s my problem:

The original tray was fitted flush to the floor (in 1994) – as you can see, the mortar has been chased out to do this. What would you do now to replace it – go down the same road, or have a raised tray, to allow future access if necessary?

My builder cousin (who’s in England, so can’t do this for me) says he’d have a raised tray every time, but would build a wooden frame rather than use those little riser kits. What do you think?

If I stick with a flush tray, presumably there’s some kind of 2-part drain which lets you install the bottom bit, then just slide the top section, sealed to the tray, down into it? Otherwise can’t see how you’d fit it, when there’s no access underneath…

Hope somebody’s still awake… thanks

PS standard 760 x 760 tray

 

[Madrab]

If you raise it up on a wooden plinth then you have the advantage of height to access the trap etc for servicing later. Make it from some 4"x 2" with a 15mm WBP plywood top, all nice and level. That might be a fun job though given the size of the hole in the floor.

It can also be sat flush on the floor too no issue there, easier to step into, as long as the trap can be set to line up with the tray drain hole. The trap is then secured to the tray from the top, not from underneath. No access for any work later though without lifting the tray.

 

[Roger465]

If you raise it up on a wooden plinth then you have the advantage of height to access the trap etc for servicing later. Make it from some 4"x 2" with a 15mm WBP plywood top, all nice and level. That might be a fun job though given the size of the hole in the floor.

Thanks very much Rob – yes, I think you're right. I’m going to shrink the size of that big hole by filling round the edges with mortar, hopefully just leaving enough space to hold the trap, and access that waste pipe if it ever needs it in future.


What do you think of these riser kits which can come with raised trays? Little adjustable leg things? Somebody told me they were crap, but my last house was a Shedrow new build, and the shower was put together that way – I used it every day for 10 years without problems, except in the last year or two I could hear faint rattling underneath when I stood in the shower sometimes.

It can also be sat flush on the floor too no issue there, easier to step into, as long as the trap can be set to line up with the tray drain hole. The trap is then secured to the tray from the top, not from underneath. No access for any work later though without lifting the tray.

The more I think about it, I think the raised one is the way to go. To get under the tray (well, actually to remove it) this time, I’ve had to remove half the tiles in the shower, and they’re not replaceable, being obsolete now – total nightmare.


Thanks again

Roger

 

[Madrab]

There are plinth kits and then there are proper plinth kits. The only ones I would ever use are the ones with 2 large thick plastic discs that are top and bottom with a the top one being very sticky with a plastic adjustable section in the middle. Seriously strong and there were 8 on a 1200 x 960mm tray. The other spindly ones I wouldn't ever consider.

Normally it's a 4" x 2" frame with a 15mm WBP ply top as a plinth. Clean/slurry the floor surface so there is no dust at all before setting the frame down onto it, ensuring it's super level.

 

[Roger465]

Thanks again - yeah, my cousin talked me through exactly the procedure you describe for the wooden frame on the phone.

I'll pop into the big plumber's merchant in Belfast on Monday and see what they've got - fact is, this is a 2nd shower, which won't get used that much, and I think maybe a decent set of risers such as you describe might be easier for me

 

[Roger465]

OK… so I’ve bought the tray, risers, front panel etc. Reading through the instructions again and again, there’s one thing which gives me a furrowed brow… this tray is very heavy, and the shower isn't a corner unit, so I can’t see how I’m going to get the tray in without destroying my back and/or dropping the tray, which is maybe what happened to the original one, cracking it, all those years ago.


Are there any tricks of the trade for this one? Especially as I’m supposed to put the risers in, lay the tray on them, adjust them, then somehow get the tray off again to screw the risers to the floor

 

[Roger465]

And another thing!

This tray is only supposed to be supported at each corner, with 17 stone me standing in the middle

In fact, its instructions say the risers can be up to 1M apart!

PS mine's the 760 x 760

These trays must be immensely strong... right?

 

[Hot&Cold]

Roger465 personally if it was my own place i would stubbornly persist and avoid a riser kit.

From your photo its difficult to see how high the 40mm pipe is in relation to the floor level but it looks workable,

presumably there’s some kind of 2-part drain

Most traps can be part fitted from above,just need to position the trap body on the 40mm pipe directly under and just touching the shower tray outlet aperture.
You could use different 40mm solvent weld fittings to alter the angle and raise the pipe if necessary also knock some more of the concrete floor out,when the pipe & shower trap body is in the correct position.Fill in some of the bashed out concrete,make a shutter to keep the concrete away from the drain pipe.
Once the concrete has started to dry,use some adhesive on the floor.Put the tray into position,line up the waste and ensure level.Now the top part of the shower trap can be fitted.
This interesting vid from about 2;30 onwards shows a shower waste body in the floor recess,with mcalpine shower traps a tool is supplied to tighten the upper part.

 

[Roger465]

Roger465 personally if it was my own place i would stubbornly persist and avoid a riser kit.

Yeah… thing is, can’t remember if I mentioned above, but many years ago (I’ve only been here less than a year) dry rot got all through the place, which I traced to a cracked shower tray. Been a lot of work to put it all right, but now I’m a bit paranoid about leaks under the tray – funny enough, suffered a lot from leaking taps etc under baths in previous houses - must be a jinx!


So I’d like to be able to stick me hand in round the trap now and again for a few weeks after fitting everything.

From your photo its difficult to see how high the 40mm pipe is in relation to the floor level but it looks workable

There’s about ¼” or ½” underneath I think. That pipe can swivel from side to side – does that mean it’s a push fit into the bit in the floor? Sorry, I’m pretty handy, but REALLY ignorant when it comes to plumbing…

You could use different 40mm solvent weld fittings to alter the angle and raise the pipe if necessary also knock some more of the concrete floor out,when the pipe & shower trap body is in the correct position.Fill in some of the bashed out concrete,make a shutter to keep the concrete away from the drain pipe.

I was thinking maybe something like that. If I DO use the risers, I'll have loads of room for the trap... the tray manufacturer says attach the trap to the tray, lower it down and screw it together etc – easy to say, but the angle of the adapter thingy they’ve supplied with the trap is completely wrong for that grey waste pipe – would you just make a bend up with solvent weld fittings? Can you buy sort of assorted bags of different shapes of these, or do I need to figure it all out in advance?



I have a McAlpine trap with the little tool, yes – it was recommended. I’ll watch that video now – but my problem I think will be in lining the tray waste hole up with that grey pipe, and getting a good seal somehow.

 

[Hot&Cold]

when you get a chance,put the tray in position and draw a circle through the waste aperture,take tray out and photo the floor.Post the photo here.Helps to work out what fittings will be needed.

 

[Roger465]

when you get a chance,put the tray in position and draw a circle through the waste aperture,take tray out and photo the floor.Post the photo here.Helps to work out what fittings will be needed.

Thanks. Not sure I can do that though... the tray is very heavy, and the shower is a 3-sided cubicle... I'm not sure how I'm going to get it in, or if I can ever get it out again once I do

Maybe I need to pay a plumber

Ummm... just looking at Screwfix though... could I use something like this to avoid awkward angles joining the trap to the existing grey waste pipe?

 

[Keithmac]

Can you not fit 3 big load bearing batons on the 3 sides then slide it in from the front?.

 

[Roger465]

Can you not fit 3 big load bearing batons on the 3 sides then slide it in from the front?.

Yes, that might work, mightn't it... I'll have to measure the space (the en-suite is pretty cramped) and see if I have some wood.

OK, thanks mate - best leave it with me for a while, to stare at some more, and re-read your posts etc, then I'll move forward again... cautiously...

 

[Keithmac]

I'm same as you, a worrier!. All the traps and the bath plumbing is easily accessible to keep an eye on it every now and then!.

If you can slide it into position it'll save your back!.

 

[Roger465]

Right. Don’t know if these pictures help at all, and I’ll have to do some more careful measuring in the morning I think, but for now… the place where the new trap needs to be seems to be the same as where the old one was, as far as I can tell – I’m guessing maybe all showers with corner drains have them in the same position…?

If that’s true, and I can join them up OK, with welded joints between the pipework so that I can be fairly sure it will NEVER leak, then it’s just a question of making sure that pipe is the exact right length to position the new trap in precisely the right place – then I could lay the new tray flush like the old one, and forget all about risers, front panels etc etc.

The other thing is though, if I get the existing grey waste pipe perfectly horizontal, I don’t think the new trap will be quite high enough – probably only a small gap, but then if I raise it further to mate with the top bit, it’d be at a slight angle, wouldn't it, which might stop it sealing… and if the tray was flush, I’d never know. THAT’S the sort of thing that keeps me awake at night!

You see, despite what you say, Keith (passes the blue Valium), I can swing back and forward between two solutions in cases like this, when there doesn't seem to be a clear-cut answer…