Can I run my ensuite waste into the existing soil stack?

deshg · 19 May 2011

Hi everyone,

I am looking at buying a new house which currently only has 1 bathroom and a massively oversized bedroom so i would like to add an ensuite. Both the bathroom and bedroom are on the top floor of a large victorian house and one of the other flats owns/uses the ground floor and gardens. As a result adding a brand new soil pipe down the back and digging it into the drains would most likely be a bit of a nightmare. Is it legal/allowed within the regs to run the new soil pipe (for the toilet/shower/sink in the new ensuite) out the back wall and then join it into the existing soil pipe (that currently services just the main bathroom) as this would make it all much easier?

The only reason i ask was when i added an ensuite to a house a good few years ago i'm sure we had an issue with this and were told to use a totally separate soil stack (but that may have been because it was cast iron).

Thanks so much for your help everyone,

Dave

adlplumbing · 19 May 2011

don`t see why not as long as you tee every thing in to regs

deshg · 19 May 2011

Hi adlplumbing, thanks so much for the super speedy response! So there are no building regs preventing me from using one soil stack for two toilets?

Thanks so much,

Dave

denso13 · 19 May 2011

deshg said:
So there are no building regs preventing me from using one soil stack for two toilets?

No problem with that. If you imagine a block of flats, one stack can serve several toilets.

alex444 · 19 May 2011

Main things to consider are maximum lengths set out in Building regs part H. (6 metres for 100mm soil pipe)

and fall/slope. (a minimum of 18mm per metre)

If you stick within these you are much less likely to have any future hassle with blockages etc etc.

Alex

adlplumbing · 19 May 2011

denso13 said:
deshg said:

So there are no building regs preventing me from using one soil stack for two toilets?

Click to expand...

No problem with that. If you imagine a block of flats, one stack can serve several toilets.

you do need to keep gaps between pipe the pipe entering but i can not rember excate gaps required

sheffplumber · 20 May 2011

got it wrong alex

Richard C · 20 May 2011

OP; need more info regarding location/distance etc & what you’re proposing is notifyable so your going to have to submit a Building Notice (fee required) so its important you get it right. I don’t know who told you about needing a separate stack because the original was cast iron but you were fed a line, it’s total crap; pun intended

There must have been some other reason.

alex444 · 20 May 2011

well sat looking at building regs part h, I was slightly out on the slope (by 9 mm) but it clearly states 6 metres as max branch length.

Perhaps rather than pick at my advice you could offer the op some of your own.

If anyone would like a pdf copy of building regulations part h you can post your email and I will send it to you.

Alex

denso13 · 20 May 2011

Hang on a minute. The OP asked if one stack can take more than one toilet to which the answer is yes. Don't go complicating things and making up your own questions. A building notice/permission will be required when all the technical issues will be ironed out.

alex444 · 21 May 2011

Nobody is making up questions, its just general advice on the topic of waste branches, yes more than one wc can go into a stack, and yes if it is a room that has never had a wc installed before you do need building regulations approval.
Pretty sure it mostly covers the strength and stability of the floor plus ventilation/extraction and the drainage regs.

But its also important to remember falls and max lengths when positioning a wc/ensuite room otherwise you will end up with future problems.

Funny how this site is for passing knowledge and advice to those that need it but most people use it to nitpick amongst each other, it's not an 'I'm better than you contest'

Also pretty important to state that building regs approval and planning permission are two completely different things and the best website to find out which one you need is http://www.planningportal.gov.uk/permission/commonprojects/kitchensbathrooms/

Alex

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Can I run my ensuite waste into the existing soil stack?

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