Plumbing question

[skier-hughes]

Can I run the waste from a downstairs wet room shower, along with the waste from the sink underground to join the waste from the toilet?

In short, the downstairs toilet blocked, in trying to clear it noticed water coming up from outside, dug up concrete to find that the clay waste pipes had cracked.
They also went uphill before they went down to the inspection chamber, and they weave round like intestines!! Due to the fact they used to go to a septic tank and then changed to mains drainage, but didn't take a direct route. See picture,
All the toilet waste is underground.
Adjacent and connected to the waste pipe is the waste from the sink, toilet overflow and a washing machine, in the utility area. This goes into a p trap level with the surface, with the 3 waste pipes discharging into the p trap from above.

Jo has ruptured her achillies tendon, and finds it hard to get over the lip to the normal shower tray, so we thought we'd install a wet room by extending the toilet room into the utility area.
The floor of the wet room would be level with the ground level now, but obviously draining to one side.
This means I need to dig up the concrete floor that is there now to fit the new shower floor, but can I dig a channel and fit the waste underground in a similar fashion to the toilet waste, with the waste from the sink connecting into it half way along?

I'm not sure what'd happen to the toilet overflow in this scenario though??
I've also looked at sites like screwfix but cannot find any type of fitting to take a small waste pipe to a large one.

The sink connection isn't essential, I just thought it'd tidy up the outside, but I can't see a way of having a below floor level drain going in to a floor level waste

I'm currently digging up all of the old clay pipes so I can dig down so that it falls from the house to the chamber and takes a more direct route and thought I'd gain some help if possible to give me some knowledge and gauge whether it's a job I can do, if I need to call in a plumber to sort it or I'm breaking all of the rules under the sun.

 

[robgil]

You may need a vent , otherwise when you flush the toilet it could empty the traps.

 

[skier-hughes]

What's a vent and where would it go?

 

[Flyfisher]

A vent allows air to be drawn into the pipework, which can be necessary when water is flushing through. If there's no way for air to get in then a negative pressure can build up and suck the water out of the sink and of the traps. In itself this doesn't do any harm as such, though if a trap is fully emptied then smells from the pipework can get indoors. Many (most?) installations have an outside pipe extending up a wall and above the guttering, which allows air to enter the system and any smell that does escape from this pipe will not be noticeable at such a height (is the idea). But where such a pipe does not exist or is not practical an internal "air admittance valve" can be fitted somewhere convenient. We have one in a separate bathroom and it works fine, if a little unsightly. They are often called Durgo valves. http://diydata.com/plumbing/air_admittance_valve/air_admittance_valve.php

Regarding the toilet overflow, I've used a cistern/ball valve assembly that incorporates an internal overflow. If the ball valve fails for some reason the excess water is discharged through the pan rather than a separate pipe. Might be worth considering.

When plumbing in our utility room/cloakroom I had to connect two sinks, dishwasher, washing machine and shower to a single waste pipe, so I used 50mm pipe for the 'backbone' which seems to be a bit non-standard for the main DIY sheds. But it was easy enough to find the required adapters to smaller pipework at a "proper" plumbing merchants. I used welded joints for most of the connections and all of the inaccessible ones.

Jo has ruptured her achillies tendon, and finds it hard to get over the lip to the normal shower tray, so we thought we'd install a wet room by extending the toilet room into the utility area.

I know achilles tendons can take a while to heal but it sounds a bit of a drastic reason for installing a wet room, unless you wanted one anyway.
Poor Jo, give her my regards.

 

[MdB]

What's a vent and where would it go?

You also want to read this: http://www.planningportal.gov.uk/uploads/br/BR_PDF_ADH_2002.pdf

 

[skier-hughes]

There is no soil stack at present, the toilet waste went straight from toilet to the sewer, all enclosed. Should I have one?

Hopefully as this will be a long term - die here - house, it may be easier to shower downastairs in later life.
Alos, we have a couple of elderly disabled relatives who'd be able to stay over, plus if we wanted to supply shower adn toilet facilities to our caravanners this would mean we could do without building a seperate block which we can't get planning for in green belt. Plus it's handy for when I've been working in the garden or the house to not wander dirty through it, Abi hates me when I do that!!!

Working on reading the rules!

 

[Flyfisher]

There is no soil stack at present, the toilet waste went straight from toilet to the sewer, all enclosed. Should I have one?

I don't know about the latest regs but we have one without a soil stack (the one with a Durgo valve) and it works perfectly well.

. . . it may be easier to shower downastairs in later life . . . . Plus it's handy for when I've been working in the garden or the house to not wander dirty through it

Our rationale was similar; not so much the later life bit but definitely for being able to shower after a hard day's hot, sweaty, dusty and dirty work outside - plus Mrs FF regularly swims in the river in the summertime so it's handy for her not to traipse through the house in a wetsuit (I did think about one of those outdoor shower heads but I thought that would be taking things a bit far!).

 

[skier-hughes]

I'm trying to find an image of how to install a durgo valve and failing May just get a plumber in!!

 

[MdB]

I'm trying to find an image of how to install a durgo valve and failing May just get a plumber in!!

http://www.google.co.uk/search?q=durgo+valve+instal&hl=en&client=firefox-a&hs=Z3n&rls=org.mozilla:en-GBfficial&prmd=ivnsfd&source=lnms&tbm=isch&ei=tXdqTseCCs688gPEqYUx&sa=X&oi=mode_link&ct=mode&cd=2&ved=0CCIQ_AUoAQ&biw=1706&bih=956#hl=en&client=firefox-a&hs=e3n&rls=org.mozilla:en-GB%3Aofficial&tbm=isch&sa=1&q=durgo+valve+install&pbx=1&oq=durgo+valve+install&aq=f&aqi=&aql=&gs_sm=e&gs_upl=10678l10678l0l10920l1l1l0l0l0l0l216l216l2-1l1l0&bav=on.2,or.r_gc.r_pw.&fp=78543b75082be841&biw=1706&bih=956

 

[Flyfisher]

Have a look at the regulations in section 1.7 in MdB's above link. That seems to suggest that a toilet may have a direct connection in some circumstances (like your existing system perhaps?)

A Durgo valve is simplicity itself to install - it just pushes into the top of the soil pipe (see the link in my above post) - so I don't think that will be any problem for you. A bigger problem may be to arrange the soil pipework itself to accomodate both the toilet and the sink and shower waste. A lot will depend on your physical layout constraints.

In our bathroom without a soil 'stack' extending above the roof gutter, the soil pipe is in the corner of the room and drops through the floor to run down the outside wall (the bathroom floor has a slight jetty over the ground floor, so quite a simple installation). The soil pipe extends to about 2 feet above the bathroom floor. The toilet discharges into the soil pipe via a standard Tee. The sink wastepipe also connects into the soil pipe.

The Durgo valve is a simple push-fit into the top of the soil pipe and prevents any smell from the soil pipe entering the bathroom.

A bit like this:

 

[robgil]

A vent is also to allow any positive pressure build up from the sewer to escape, a durgo will not allow this to happen. Is there an open vent anywhere in your system?
Also if getting someone else in to do this kind of work, for drainage I would get quotes from ground workers for gully etc , it will be miles cheaper. :wink:

If your system has an open vent somewhere, and it all works I wouldn't bother with a durgo. It's fixing something that isnt broken at extra expense.

 

[Flyfisher]

Can the open vent be anywhere? If it's downstream of the toilet (and nearby sink/shower waste) isn't there a risk of negative pressure (from flushing) emptying the sink traps? If not, then I'd agree that the Durgo valve wouldn't seem necessary.

As for positive pressure . . . I don't even want to think about that! :shock:

 

[MdB]

It appears from your drawing that the shower / sink connection is going to a gully hopper thing outside the property. This will allow air in / out so I think you can get away without a vent as the toilet can't empty any traps. You will need an inspection chamber at all junctions / bends in the new underground pipe.

 

[robgil]

You mention your levels on the clay pipe run uphill?
This is what I would do , put a durgo behind the shower drain, run everything in new plastic and replace the lot.

To deal with positive pressure an open vent anywhere will work. If that is a gully your shower and basin discharge into and you dont want to make it redundant with new pipework you can have the vent there and it will work.

 

[robgil]

It appears from your drawing that the shower / sink connection is going to a gully hopper thing outside the property. This will allow air in / out so I think you can get away without a vent as the toilet can't empty any traps. You will need an inspection chamber at all junctions / bends in the new underground pipe.

A gully still needs a water seal doesnt it?

 

[MdB]

A gully still needs a water seal doesnt it?

Good point but doesn't the inspection chamber required where is joins on to the main pipe deal with the problem of syphoning the gully?

 

[robgil]

It may do , providing there is an inspection chamber.
A tip is to get groundworkers out to give you quotes. When I was trying to figure out what to do with my drains I got a few quotes with the intention of simply finding out the easiest way to do it myself.

 

[Lime]

Can I run the waste from a downstairs wet room shower, along with the waste from the sink underground to join the waste from the toilet?

In 4" pipe, yes you can as long as installation complies with all the building regulations.

Anything smaller should be accessable.

Sharing the same small pipe (sink and shower) will cause no end of problems and contravenes building regulations.
Backflow WILL occur from the sink to the shower.... even if it is vented.

 

[skier-hughes]

I'm well and truely flumoxed.
The shower cannot drain into the open drain outside as it will be around 6" below it.
Upstairs we have a shower waste with the sink connected to it via a T junction in the ensuite, which then connects to the outside soil pipe.
In the bathroom we had sink and bidet on the same waste run, with bath adn toilet on seperate ones.
I don't have a soil stack so simply putting it on top of one, isn't, well simple!!!
Putting a soil stack in the shower room as per robgil's diagram, I think, is aesthetically not on.
The problem with the direct route is that it will cross with the ensuite waste which also joins the inspection chamber, my diagram isn't quite accurate with the angles of the direction of flow, but is close.
I could make it similar to Fly's diagram, keeping the outlet from the toilet at 90' to the floor and have a soil stack next to the toilet, run the sink waste in above the toilet and the shower waste below, but this would still need to be below ground level.

I could use the p trap outside to discharge the waste from the washing machine and sink as previously done and if this gives me a vent that's fine, but I still need to get my underground waste from the shower into the system somewhere? It will be below floor level at the shower end adn obviously fall from there!!

 

[skier-hughes]

Here's a pic showing what I thought I might be able to do, simplicity itself