Shower connecting into side of horizontal soil pipe downstream of WC

[4StringBass]

Hello!

I am in the midst of ripping out our old ensuite and notice that the shower waste pipe connects into the horizontal soil pipe on the side, not the top.

The horizontal pipe sequence is: WC (at the end), washbasin (top entry), shower (side entry) then connection to vertical pipe with vent rising on the bend. The vent is about a metre from floor level. All pipework is inside the house

Our old shower was raised up above the floor on legs, but our new one will be flushed into the floor.

I am concerned of WC waste water entering the shower tray (and to be honest I'm surprised it hasn't happened before). There is not enough room to move the connection to a top mount.

Will a non-return valve be sufficient to prevent this or will I need to run a separate horizontal for the shower and connect this into the vertical part of the soil pipe? As the soil pipe is already vented, will I need a further vent for the shower?

As much as it would be a bit of a faff, running a 40mm pipe into the vertical would not be a major hassle.

Thank you for reading this!

 

[Madrab]

Do not use a non return if you can avoid it and of so then it needs to be easily accessible as they tend to block. Ideally you want a separate shower waste run into the vertical stack.

If the shower is into the already vented stack then no, no other vent should be required.

 

[4StringBass]

Thanks Madrab, much appreciated. Time to rip the pipe boxing out!