Soil Pipe Addition

[kiwikent]

Hello, we are putting a new loo in upstairs and I am tapping into the existing soil pipe, looking for some advice as to where to and what fittings to use. The pipe will come from the left of the picture and I am worried that if I go straight in with a tee I might get back wash into the down stairs loo. As the pipe from the downstairs loo bends straight from the wall wondered how I get around that. Or do I run it past the bend on top and drop it in.thank you in advance.

 

[joni os]

Use Tee, most of which incorporate a radius junction. Provided the radius complies with direction of flow there should be no problem.

 

[kozak1968]

Looks like there is a back fall on the pipework to the existing w.c. you may want to rectify that first.

 

[chris watkins]

You would be well advised to run a new float (horizontal pipe) from your new upstairs WC & branch it into the vertical stack at high level, of course what we can't see is the route which is out of shot in your photo.
Please remember all your work needs to comply with the (Law) Building Regulations AD Part H, which you can download free.