shower waste through timber floors help?

[mutley racers]

Hi, I am needing to know what kind of trap to use on my shower tray. As it is going though 18mm ply and then 12mm ply on top. So it needs some depth. Also, I need to be able to connect it begoe putting it in place. So with a flexible waste as I can't get to waste through joists. So will need a flexible waste or something. The waste the shower tray has come with does not seem to have enough depth on its outlet to get through the floor structure to connect the waste pipe.

I hope that makes senses

[AWheating]

mc alpine do a good range. even one that connects at the bottom.

90mm Shower Traps - Traps | McAlpine Plumbing Products

[Best]

Agree, Mc Alpine traps. The bends on them when turned downwards obviously drop away from the floor, so there will not be a problem hitting the floor but you probably will have to cut a bit out of the ply floor where the waste bend is. You may wish to use a square bend to then join level from the angled waste bend.
Tip for doing all this is to set the tray in it's exact spot & mark the waste hole on the floor. Remove tray & mark a very large cross through centre of circle - so you never lose the centre mark after cutting the hole. Cut the floor a bit bigger than the outside of waste fitting including a bit above the bend if it has a high bend. I would put accurate wood supports in below the waste to hold it almost to it's needed height. Check the waste is dead centre on your cross & you can't go wrong. All you have to do is bed the tray & tighten threaded waste into the trap from above.

[mutley racers]

Thanks for the replies guys. Mcalpine trap it is. when you say bed the tray, do you mean with sand and cememnt as mine is flush all around the botton, apart from the kind of moat. Also, you say just tighten from above, but how do you know if you don't have a leak as it is not possible to check when the floor is down and all joists in the way. is it just a case of a silicone on the threaded flange to the shower tray

[mutley racers]

so basically, all you really do is cut out the shape of the trap with the bend into the wooden floor? I was worried that this would weaken the floor. But, as the shower trays load is spread, it wont really effect it much

[stevetheplumber]

best to put nothing on the threads these traps are pretty near fool proof silicon tends to allow the washers to twist out when tightening and its unnecessary
you realy only need to bed them on something if the floor is uneven when they are down on clean board i just silicon the edges

[AWheating]

should be fine, chipboard floors are the worse for strength after cutting a hole, if it weekens then cut a large section out and replace with 18mm exterior ply bracing any joints. You may be better to bed the tray on extra flexible tile adhesive.

as soon as the tray is in and trap sealed run plenty of water down it to give it a good test.

[mutley racers]

Cheers AW.

[mutley racers]

oh really steve, The mcalpine trap that came with the shower said to add silicone to it? I think i will go with that steve, the floor is level and its a proper resin tray. Not a plastic one. So heavy it is

[Best]

Usually I find even on the most level floors you need to bed the trays unfortunately.
I like that idea of extra flexible tile adhesive - much better & easier to bed tray than sand & cement.
Cut the hole in the plywood for the trap rounded, so not to weaken floor too much.
If possible, have a trap in the floor to view the finished waste to check for leaks when you test tray with a lot of water, but often you will just have to do a fussy job & you will be sure it is sound.

[mutley racers]

When y2k say cut the hole rounded, do you mean to the diameter with the outlet from trap? As otherwise, the outlet isn't deep enough to go 30mm under the ply? Trap in the floor, you mean by making a joint in the floor with the ply and not one whole sheet?

[Best]

When y2k say cut the hole rounded, do you mean to the diameter with the outlet from trap? As otherwise, the outlet isn't deep enough to go 30mm under the ply? Trap in the floor, you mean by making a joint in the floor with the ply and not one whole sheet?

Round hole in floor a fair bit bigger than diameter of trap just in case the accuracy of the measurement was slightly out. Plus a bit for the waste bend & round the end & you will have a cut out like a light bulb shape, which is really the minimum cut. Just was saying this because it is good practice & frankly most jobs I see, the floor has a large rectangular bit removed or, chipboard smashed with a hammer!
A piece of the plywood floor cut out ("trap" as I call them) will not weaken the floor if it is cut on top of joists & supported where it crosses them by using something like 2"x1" batons centred along the edges & a few screws through the top of ply & into the baton. That's if you feel you need to have a piece of floor cut out.

[mutley racers]

Awesome. I feel I am fully equipped with the knowledge I need to put my first low level shower tray on the timber floor. Thanks for all your help guys

[mutley racers]

Well chaps, that was easier than expected. Thanks for all the help. I would have made a right dodge up without the advice.

Now another thing. About a month ago I posted a thread about connecting plastic to cast iron soil pipe. Into the collar I was asking about. But after finding out it was 31/2 inch I had to just use a French on the lead coming out of it. But now, I have one that is 4inch and so I cut the cast iron back to a collar. Or what I thought was the collar, and there was no brass like what was suggested in last thread. And, the connection seems to be bordering the very edge of the collar, if it is a collar. So, I shall send you a pic to see what options I have.

Thanks for all your help on the shower waste guys

[mutley racers]

here we go. This is what i am talking about...2012-09-25 15.51.47a.jpg2012-09-25 15.51.43b.jpg2012-09-25 15.40.48c.jpg

You can see the faint line of the end of a pipe i think in the collar, so can this be taken out and one of those rubber connections put in?