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

 

[josh]

should be fine as long as you'v got fair fall, i would make sure the new soil pipe is vented in the bathroom with a dirgo due to the long run and yes teeing into the soil pipe for the basin and bath is fine. I would take a seperate waste pipe for both basin and bath directly into the soil pipe, no potential issue of the basin coming back up in the bath and eliminates possible gurgling of the other trap when one is let go.
Have seen a chap add a ensuite to a bedroom running the soil pipe through the bedroom, he made a right hash of it and if i bought the house first thing i would do is rip it all out.

 

[ajc1976]

Thanks for that.

the AAV....is that to prevent the WC seal from being siphoned, or the seals on the bath and basin?

will it need to be a 4 inch AAV or can I reduce to an 1 1/2?

 

[josh]

Yes and to help the water get away, normally if you can use a 4" one do so, i'v only used the small ones a handful of times and i believe there more for if you were venting the waste pipe.
The AAV will need to be above the spillover level of the WC, so above the top of the pan unless stated can be fitted below it which i have seen before.