Loo waste to soil pipe max length

[MisterMuddle]

Hi! I'm fitting a toilet & sink in my bedroom. The new loo's waste will be coming out of the same wall as the existing bathroom loo, but the distance between the new toilet and existing (cast iron) soil stack is approx. 12 ft. Is this a problem?
Any help greatly appreciated!

 

[chrishutt]

You can check Building Regulations Part H on the ODPM web site. This will specify maximum lengths and falls, etc.

 

[MisterMuddle]

Thanks for that link! It looks like the permitted branch length is 6 metres on a slope of 18mm per metre, so my new branch will be joining the soil stack below the existing one. Great! I will be punching a relatively large hole in my twin wall (1930's build), but am wondering whether to also remove the existing cast iron soil stack and replace it with modern modular components. Any ideas or experiences about this?

Thanks again!

 

[chrishutt]

The usual thing when making a ranch into CI stack is to convert to plastic at some convenient point below the new branch and back to CI above, unless it's simpler to replace the whole remaining vent pipe above with plastic.

However it sounds as if you have an existing CI branch just above the new branch location. This may require some ingenuity to adapt to - fittings do exist but you might need to search the main manufacturers' web sites.

It might be worth looking at some sort of new CI branch (Timesaver?). It will be expensive but might be less trouble in the end. Also see this //www.diynot.com/forums/viewtopic.php?t=28223.

 

[MisterMuddle]

The usual thing when making a ranch into CI stack is to convert to plastic at some convenient point below the new branch and back to CI above, unless it's simpler to replace the whole remaining vent pipe above with plastic.

That's a great idea! I'll cut the CI pipe at the point where the new branch will go, and replace everything above with new plastic parts, even if I have to remove & replace the CI pipe in my present toilet. Do you know of any online catalogues (UK) that show all the necessary parts I need? I read on another post here that there is some sort of 'coupling' to connect the new sink waste (32mm) to my proposed new branch. Is that a wise move?

Thanks a million for your help!

Shaun

 

[chrishutt]

You should be able to find the main "players" (I hate that expression!) by googling, but a few names are Hepworth, Marley, Hunter, Osma and Polypipe.

 

[tawelfryn]

i have always followed the rule; 1 in 40 fall for 4" pipe; 1 in 60 fall for 6"pipe

 

[MisterMuddle]

I guess my proposed fall of 18mm per mtr is fine then!
Thanks to everyone for replying - I've learned a lot from this forum, & the archived info is priceless.

Cheers,

Shaun