Getting bathroom waste right!

[myrile]

We are doing up an old wreck of a house, but have been left in the lurch by a dodgy plumber. He whacked pipes in wherever, and they aren't compliant with Regs (grr). I was hoping you might be able to offer some advice to help us get past the LABC man...

First one - our bathroom sink has a very long run to the (external) stack, which takes it the length of the bath. Can I tee it into the bath waste to save on pipe / holes in the wall / stack connections? Alternatively, I was thinking of putting in an internal stub stack and AAV just to be sure.

Second one - there's a "laundry" room, with minimal pipework in place. Can I connect washer and dishwasher to a single pipe? Worried about siphonage! On the same topic, do I need to put in a trap internally (or a trap per appliance), or can I take the pipe straight outside and through the external bottle trap?

 

[mikeyd]

First question: I'm not a plumber but the 32mm waste from my sink connects in to the 40mm bath waste under the tap end of the bath and the pipe runs the length of the bath before meeting the outside wall. Never had a problem.

Second question: Don't know what you mean by an external trap (not outdoors surely) but it's usually down to manufacturers instructions. You probably can't go far wrong with something looking like this:

duplicated and the outlets connected together before going external

 

[dextrous]

Op, what makes you say that the plumber's work isn't compliant?

 

[myrile]

The rather disapproving LABC man on his first visit.

He mostly focused on the ensuite (hence no questions there) - I don't think he realised the extent of the changes in the main bathroom!

Specifically, the plumber had put 2 90deg bends into a toilet waste, running it along an internal wall before it went outside. He'd made a hash of the new external pipework too, but some quality time with LABC man and then Regs have me feeling pretty happy with all that.

 

[mikeyd]

Who planned the bathroom? Most important thing is that toilets go up against an external wall or as near as possible.

Anyway, did my previous post help at all?

 

[myrile]

Not to worry mikeyd, we didn't do anything daft with the loo It is (and always has been) against an external wall - so the waste now goes straight outside, and then on an appropriately angled branch down into the stack!

Thanks for the diagram on the laundry appliances - sounds like you think we do have to trap each one individually, which is a bit of a pain. I was very much hoping they could share. I'll see what I can find in way of manufacturer instructions (machines not delivered yet).

 

[eddiespaghetti]

We are doing up an old wreck of a house, but have been left in the lurch by a dodgy plumber. He whacked pipes in wherever, and they aren't compliant with Regs (grr). I was hoping you might be able to offer some advice to help us get past the LABC man...

First one - our bathroom sink has a very long run to the (external) stack, which takes it the length of the bath. Can I tee it into the bath waste to save on pipe / holes in the wall / stack connections? Alternatively, I was thinking of putting in an internal stub stack and AAV just to be sure.

Generally, if you up the bath waste pipe size to 50mm you can connect a WHB on the same run as a bath. However, there are limits on the maximum length of run and you'll have to consult your BC officer again and double check he's happy with it - they're anything but consistent. The AAV is not strictly necessary, but should you wish to install one it would need to terminate above the spill level of the basin and be accessible.

Second one - there's a "laundry" room, with minimal pipework in place. Can I connect washer and dishwasher to a single pipe? Worried about siphonage! On the same topic, do I need to put in a trap internally (or a trap per appliance), or can I take the pipe straight outside and through the external bottle trap?

Large diameter stand pipe with trap - feed both flexi drainage pipes from DW and WM in (As in the diagram someone posted above) and you're done. (Bear in mind the diameter of the pipes may require a tee above the trap but a single trap is sufficient)

 

[dextrous]

Nothing wrong with attaching a double spigot fixing to the pipe that mikeyd drew for you.

 

[Hugh Jaleak]

Should be ok connecting basin waste to bath waste, anti vac trap on basin may be an idea. Stops basin trap being siphoned when bath empties.

Laundry room, you will need an internal trap on the pipework, usual solution is a standpipe, like this: http://www.screwfix.com/prods/18640/Plumbing/Wastes-and-Traps/Washing-Machine-Trap-40mm
McAlpine do a fitting that connects to the top of the standpipe, part no. V33WM

Cant get a link to work, but McAlpine have a website if you wish to look, alternatively independant standpipes for washing machine and dishwasher, then tee them into the same pipe. This waste pipe will need to be min 40mm dia from standpipe(s) to external (think you mean gulley!).

 

[mikeyd]

sounds like you think we do have to trap each one individually, which is a bit of a pain.

Not necessarily, I just suggested a failsafe option. I'd guess they could share a trap, my dishwasher shares a trap with the kitchen sink. I'll leave it to the resident experts to give further advise.

EDIT: see above, (must type faster)