Two bathroom basins, sharing 1 x 40mm waste - ok?

[Simes123]

As per the subject, it would be much simpler for me to run 2 x basins (main bathroom, and next door en-suite) joining via a swept tee into 1 40mm waste boss into the stack. Pipes will be 40mm throughout (unless that is unnecessary).

Is that compliant? I know I'm best running separate wastes, but if I can use 1 boss on the stack, it will hugely simplify the boxing in task. However, I do want the install to be compliant with BRs so will do what is correct in any case. Appreciate any help - about to order the porcelain, and 2 sharing 1 will equal 2 pedestals (preferred), and 2 separate will require me to use an inset vanity basin and build a vanity unit (not preferred!).

Thanks.

 

[Dan Robinson]

It should be OK with the correct fall - 50mm would be better.

 

[muggles]

Maximum run on 40mm is 3 metres, if you need to go further than that you should use 50mm. Recommended fall is 44mm per metre

 

[Simes123]

It should be OK with the correct fall - 50mm would be better.

50mm just seemed a little excessive for 2 x Basins, when 32mm is ok for one. I thought going to 40mm (50% more area) would be ok. Don't think anyone makes a 50mm pedestal trap?

 

[Simes123]

Maximum run on 40mm is 3 metres, if you need to go further than that you should use 50mm. Recommended fall is 44mm per metre

Hi - the Run on 1 is about 1 m, and the run on the second is about 1.5m. They'd join a swept Tee about 20cm from the Stack. (The bathrooms are adjacent thru a stud wall).

 

[Dan Robinson]

The 50mm doesn't have to come all the way up.

50mm off the stack. Then branch off into 32mm to the traps.

 

[Simes123]

Presume I'd only need 50mm for where they join together - ie the last 25 cm or so?

 

[Dan Robinson]

40mm will be fine then. I ththough you were talking aabout much longer runs. Just make sure the fall it good and if possible stick rodding eyes in.