Bathroom Waste.

[chuzal]

Hi,

Hoping someone can give me some advice.

I’m moving my bathroom from downstairs to upstairs.

The bathroom is moving to the room directly above where it is now.

My question is, would it be more benifical to run the bath and sink waste into a horizontal soil stack or would it be best to run the appropriate size waste pipes into the vertical stack?

There should be three pictures attached:

First picture is the layout of the bathroom (The vertical stack will be entering upstairs near the toilet)

The other two pictures should show what I’m trying to describe re options.

Either option will mean boxing pipe work in, in both the upstairs and downstairs room, which I’m not concerned about, I’m more interested in better drainage etc.

Thank you

Martin

[chrrris]

Either option is fine, as long as the pipe lengths don't exceed the maximums given in Part H (from memory, I think that's 1.7M for 32mm, 3M for 40mm, or 4M for 50mm). I would personally go with the first option (with rodding access) if the permitted lengths allow it, because most people consider 40mm or 50mm pipe on the outside of their house to be less intrusive than a 110mm (assuming the pipework will be on the outside of the house, that is...)

[chuzal]

Hi Chrrris,

Thanks for the quick reply.

No, this will be an internal stack. The vertical stack will run up through the joists, into the room above.

I was concerned that the bath waste may be too long, although it should fall under 4m in total length.

[chrrris]

Okay - the reasoning is basically the same regardless of whether the pipework is inside or outside. 40mm or 50mm for the bath waste is usually easier to hide (in between joists if there is a route, or boxed in behind a false wall). There's no harm in doing it in 110mm if you have a suitable plan for hiding it, but no need to unless the branch length is >4M (and to be honest, it's not that uncommon to find longer branches than that, even though it doesn't conform to the current building regs).

[chuzal]

Thanks Chrrris.