slope question about relocating WC soil pipe

[James345]

Hi,

I'm doing a bathroom refurb and wanting to move both the WC and wash basin over to the right.

In the picture attached, green is how I think I should position the new WC and orange is how I think I should position the new wash basin.

I know that the waste pips should have a slope between 1:40 and 1:110, my question: can a waste pipe have a vertical drop of any height and then be connected horizontally to the branch stack at the right slope?

The previous plumber did this with wash basin waste pipe like in the picture... and yes he also didn't secure it and he didn't put a cover on the top of the branch stack, so I don't know if what he did is correct.

 

[Deleted member 120897]

Green one might not work, as you’re showing it where the wc connection is. I don’t know what cover you’re referring to either.

 

[snowhead]

Yes vertical is O.K.

 

[Ben-gee]

Yes, what you’re proposing will work fine. As you’ve alluded to, make sure it’s got a few clips to keep it straight.

 

[Ric2013]

Waste pipe branches are generally 1:11 to 1:55 (18 to 90mm fall per m run) - source: ADH. Where did you get your figures of 1:40 and 1:110 from?

Use 40mm (1.5") pipe (minimum) for your washbasin as it looks like the run is around 3m.

Yes, your plumber did not put a bird cap on the soil and vent. Realistically there must be millions installed without yet birds nesting on them is not a frequent event. Not clipping the basin waste branch is a bit silly though!

 

[James345]

Waste pipe branches are generally 1:11 to 1:55 (18 to 90mm fall per m run) - source: ADH. Where did you get your figures of 1:40 and 1:110 from?

Use 40mm (1.5") pipe (minimum) for your washbasin as it looks like the run is around 3m.

Yes, your plumber did not put a bird cap on the soil and vent. Realistically there must be millions installed without yet birds nesting on them is not a frequent event. Not clipping the basin waste branch is a bit silly though!

The falls for waste pipes is a figure I got from this chap on youtube:




He made his soil waste fall just under 1:110, which you can see at the 9 minute mark.

I'm unfirmiliar with ADH but I did some further digging and found a source that confirms 18-90:1000 fall for waste pipes. Thanks for the correction.

 

[ShaunCorbs]

20-25mm per meter for soil and 15-20mm per for waste pipe

 

[Ric2013]

ADH is the Approved Document (for the Building Regulations Part) H and shows a tried and trusted and legally accepted way of meeting the requirements - this does not mean you cannot meet the requirements in other ways, but it is what we generally go by and by and large says the same thing as the source you have looked at. You won't go far wrong with Treloar anyway.