by Stelf »
Fri Jan 09, 2009 3:18 pm
Hi
When you say a 3mtr soil pipe from the bath I presume you mean the bath waste pipe. It will require a decent fall from the bath to the soil stack and it may silt up over a period of time but if you use a spirit level and make sure you get as much fall as possible it should be OK for quite a while. It is best to run a separate basin waste pipe for the reasons given by plumbbob, but you can put a 90 degree bend on the basin waste pipe just behind the basin, pointing down to the bath waste pipe, and run the two pipes at low level alongside each other up to the soil stack. The pipes can be fitted using an anti syphon system but it is probably more simple just to run separate pipes with separate soil stack connections.
If the soil stack is inside the property, which seems like it by your post, then definitely provide access to it from the inside, do not knock a hole in the wall. Lastly a 3mtr waste pipe on the outside, which I presume is from your bath, is quite long and I would keep it inside if it was mine and box it in but fit panels for easy access.
You don't say if the existing soil pipe is upvc or cast iron which poses other problems as you may then have to remove the top section of your soil pipe and renew it in plastic from the waste pipe connections upwards.