Toilet waste

[Flyster]

I would like to fit 2 toilets into my house, one is a relocation in the 1st floor bathroom, the other is into a space under my stairs.

The bathroom relocation would take the waste pipe straight out of an external wall, turn 90 degrees, run approx 3 metres, turn 90 degrees around the corner of the house, run another 2 metres and into a fall pipe, I know the rate of fall for this pipe, but would the distance cause a problem, especially as it has a 90 degree bend almost in the centre of the run?

The toilet under the stairs would have the waste exiting the pan, turning 90 degrees downwards to go below the floorboards, then turning another 90 degrees back to run for 3 metres to another 90 degree bend that will take a short straight one metre into the soil stack. Will the 180 degree bend at the toilet and 90 degree bend along the pipe cause a problem with the flow? I have one metre of headroom under the floor boards for the full length or the pipe run.

I'll be using 100mm pipe for both wastes, the 90 degree turn in the middle of the under floor pipe will be made using a sweeping bend rather than a 90 degree elbow. I plan on putting a vented valve on the understairs pipe above the 180 degree bend and hidden in the boxed in area behind the toilet cistern.

Any help with this or pointers as to what problems I'll have would be greatly appreciated.

 

[Richard C]

Firstly, I assume you are aware that the work you’re doing is notifyable to LABC, should comply with all Building Regs. & is subject to inspection/test; that’s not just the soil/waste installation but forced ventilation (fans) & any electrics!

That’s 110mm soil pipe by the way. The maximum length for an unvented w/c branch is 6m with a minimum fall of 18mm/metre so it sounds as if you’re OK there. Apart from adjacent to the w/c, 90 degree bends are never a good idea & you should avoid them if at all possible. Use swept bends not elbows & these must/should have access from one end or the other to clear any blockages; if not fit a rodding eye. If you’re connecting basin/bath waste directly into the soil pipe, you could siphon the traps so may need to fit some form of anti-siphon arrangement on those as well. Any AAV must be installed higher than the highest overflow on that branch for obvious reasons & can only be used if another part of the foul drain is vented to open air; necessary to allow positive venting.

Read this document;

http://www.planningportal.gov.uk/uploads/br/BR_PDF_ADH_2002.pdf

 

[Flyster]

Thanks for that, I do know about having to notify the powers that be, I was checking if it would be possible before going down that route.
I've decided to leave the upstairs loo where it is as I can't avoid a 90 degree bend halfway down the pipe, the under the stair loo seems do-able though, it's a toilet waste pipe only with nothing else feeding into it so shouldn't be too much hassle to fit, joining it to the cast iron pipe is the next hurdle but after lots of reading up on other peoples questions I think I know where I'm going with that.

Thanks again.