building regs for new toilet

[ajc1976]

Hi all,

Hope you can give some advice:

I want to install a new bathroom in my house. This will involve a long branch pipe to the soils stack. It will be about 2.5m under a suspended timber floor (joists in the correct direction thankfully) then 4m outside to the vertical stack. The joists are 6 inches so i can get the required fall under the floor, then outside there are no probs.
My worry is the 6.5m run - building regs document H is confusing as table 2 states a 15m maximum run, but diagram 3 states a 6m max run (so I'm obviously 1/2m longer!)

Where do I stand here? And I assume tee-ing the new basin and bath wastes into this new branch is okay?

Thanks

 

[tony1851]

It's not a hard and fast rule, I've seen longer unvented runs than that.
Just do it and see if in practice the seal isn't broken if the existing wc is flushed. It's what works that matters.

If the worst comes to the worst, can you install a 2nd vent pipe immediately your branch comes through the wall? - a bit unsightly, though.