wet room/ concrete floor

[Mikest]

Hi, can anyone be kind enough to explain how to plumb a wet room.

The floor has been concreted and i'm left with 3" to floor level.

I have a 4inch pipe in the room (this is where the toilet will be) to which i will connect a boss connection.

What showertrap will i need? and would i need to make a deeper hole to fit the trap in? Currently i have 3inch to floor level. The fall will be to the boss conection.

Thanks in advance

 

[Mikest]

I would be really greatfull if someone could shed some light on this. The floor has already been concreted and i'm a little worried. Im not sure if the builder knows what he's doing as he is only building the shell and not plumbing the wet room.

The wet room is on ground floor.
Now that the he has concreted the floor im worried about how the piping for the shower and sink will go in. There is only 3inch left to floor level which is for screeding.

The only pipe i have in the wet room is a single 4inch pipe coming up vertiaclly. This is for the toilet. Initially i had thought he would take another 4inch connected from main drain to where the shower will be. But he was adamant that theres no need and that the shower and sink + toilet will all be connected to the same 4inch waste pipe.

Can some one please shed some light on this, Im really worrying at the thought of having to rip the concrete out. i've out of a job and cant afford extra expense. Should he have taken another 4inch pipe to the shower?

What should i do?

 

[Norcon]

Usually after the sub floor, insulation is laid then screed. That allows a depth of about 150mm to play with. So pipe falls are easier.
Regs may vary though from area to area. Thats how its done here in NI.

And yes a separate 4" pipe would be available for basins,baths wetrooms, etc.
A strap boss at floor level will leave no fall. I'd think the wetroom will flood.

 

[Mikest]

The dpm insulation and then concrete is laid. Im really worried, even more so thats youve said a seperate 4inch pipe should have been laid.

Ive looked at the boss connetors and the sockets for them are square on.
In theory how is this supposed to be plumbed to work.

tell me if this is right,

Boss connector connected to 4inch pipe (below ground level)
Toilet waist directly falling in to boss pipe.
2 or 3 inch waste pipe connected to boss connector going to shower trap.
is this right?

This is pretty much what he is thinking?

 

[Norcon]

How will you fit the strap boss below ground level if its concreted.
Break it out?
Then the pipe also poses a problem which would need to be 2" and acheive a minimum fall of 2%.
Also the wet room area will also need appropiate grades set to the gulley and lowers the overall gradient to the main floor outlet.
Sounds like a diamond saw and jack hammer is needed.

 

[Mikest]

Remember the floor is concreted upto 3inchs below floor level. Will the 3 inchs i have not be enough for the gradient to shower trap?

I suppopse to fit the boss connector i'd have to dig around the waste pipe and connect it down enough to get a fall. The toilet will sit directly on top.
I would then connect a 2ich or 3inch pipe (please advise which is best) to one arm and and connect to the shower trap.
I would connect another 2inch or 3inch pipe to another arm and take to the sink waste.

Is this correct?

If you can then please give me a breakdown of exactly how i would connect the whole waste together from one waste pipe. including all the fitting. I would be really really greatfull.

Im also told about having some sort of air trap pipe located vertically somewhere in the room. Any ideas?

 

[Norcon]

I'd aim for a 2% fall which is 20mm per meter. Same with the wet room gradients.
Use 50mm pipe and branch off in 40mm to the basin under the floor. Then reduced down with a rubber boss to 32mm with an anti syphon trap or air inlet coupler fitted.