Soil pipe between joists

[Alex_beaton]

Does building regs allow me to run the soil pipe from a 1[SUP]st[/SUP] floor wc under the floor ie between two joists. If so, are there restrictons on length or drop?

thanks

 

[Rodolphe]

Alex,

Don't take it only for me as there are some regulations experts on this forum and I am not one. I do not know that there are restrictions to putting a WC soil pipe between joists (in fact, there's one in my house that is installed just like that), but would advise to use one length if possible (no connections that might leak later) and if not possible to make super sure you get a tightness test in before you commission.

From my coursework, the limitations are as follows:
- no more than 6m from the toilet to the vertical stack
- slope is a minimum of 18mm/m.

You should find that information in the Document H building Regs, Diagram 3, page 9.

Don't forget the support brackets.

 

[AWheating]

yes its fine to run in the space between joists, lagg around it with fibre glass for sound proofing and follow the normal rules for lengths and fall.

 

[Simon F]

new soil pipe/stack will be subject to building control anyway,
or is it just a bit of an alteration??