Connect upstairs toilet to downstairs floor soil pipe

[Tyrone Thompson]

I’m not a plumber firstly, but here goes. I’m doing a loft conversion, the new bathroom toilet is directly above the existing downstairs toilet. The plastic soil pipe in the downstairs concrete floor comes up about 9 inches from the wall. (I don’t want to take the soil pipe through an outside wall as it would all be on show)

My question is, if I were to bring the upstairs soil pipe to the downstairs toilet in and have it boxed in, how do I have it connect to the soil pipe in the floor? While the toilet downstairs is also going into it?

is there some sort of double pan connector? With a side entry for another 100mm soil pipe? Or do I need to gun out the concrete floor and add a socket branch fitting lower down?

 

[Hugh Jaleak]

Firstly, how deep is the drain under the floor, Regs do not permit any connection within 450mm from the Invert of the outgoing drain. This is to prevent issues with waste falling from above blowing out the trap of the ground floor appliance.

If thats ok, then the stack from above needs to come down straight into the existing drain connection, bends really need to be avoided, as they can present various issues with flow, noise and blockages. Only real workable solution is usually to bring the stack up in the corner of the room and have the ground floor WC joining it with a junction.