Joining waste to soil stack.

[paultim]

I am planning on converting a small bedroom into an ensuite shower room. The house is about 200 years old and there have been many modifications in the past (not all of them carried out in a particularly logical way !)

On one side of the room is an existing WC waste which continues up to vent through the roof. The Shower and basisin will be located on the opposite side of the room and their waste run under the floor, parallel to the joists.

Where the existing WC enters the soil stack there is not sufficient clear space on the pipework to fit a boss to connect the new waste due to pipe junctions. Just below the joists the soil pipe turns and runs horizontally for a short distance, I can get access to the pipe here and wonder if it is acceptable to have the new waste join the soil pipe vertically from above? (ie have the new waste turn downwards and drop directly down into the horizontal soil pipe through a boss)

Should I run separate wastes for shower and baisin or can I combine them into one?

Thanks in advance for any help / thoughts.

 

[holty]

sounds ok to me.

 

[Richard C]

I am planning on converting a small bedroom into an ensuite shower room.

Are you aware you’re doing notifyable work which is subject to Building Regulations with regard to drainage, forced ventilation & electrical work? You will also need a certificate of compliance when you sell or it will be viewed as unauthorised building work & need regularisation (retrospective approval); this may not be straight forward, will be more expensive & may affect your sale.

The house is about 200 years old and there have been many modifications in the past (not all of them carried out in a particularly logical way !)

May mean what is there wont meet current B regs. but should nto be a problem to fix.

On one side of the room is an existing WC waste which continues up to vent through the roof. The Shower and basisin will be located on the opposite side of the room and their waste run under the floor, parallel to the joists.

In principle it’s OK but waste runs must have a minimum fall & there are maximum lengths for unvented branch runs.

Where the existing WC enters the soil stack there is not sufficient clear space on the pipework to fit a boss to connect the new waste due to pipe junctions. Just below the joists the soil pipe turns and runs horizontally for a short distance, I can get access to the pipe here and wonder if it is acceptable to have the new waste join the soil pipe vertically from above? (ie have the new waste turn downwards and drop directly down into the horizontal soil pipe through a boss)

Yes but not ideal; you may need to vent the waste runs to prevent siphoning the traps every time you flush the loo.

Should I run separate wastes for shower and baisin or can I combine them into one?

Separate runs are always preferred, if you combine you may need to vent the basin trap or fit an anti siphon trap.

 

[holty]

hepv0 valves come to mind. if i remeber correctly its 1.8m for 1 1/4" and 3m for 1 1/2" for max pipe lenghts.