Downstairs toilet connection to soil pipe

[mfarrow]

Hi

We're thinking of adding a downstairs toilet in the pantry with the soil pipe going through and out the garage, and would like some advice on the most practicable way of connecting into the main drain that runs in the passage between ourselves' and a neighbour's garages.

The drain is 6" diameter clay/salt-glazed and is fed (I believe) by us and our attached neighbour via a 4" pipe, and the other neighbours via a 6" pipe. I imagine the usual choice is to build an access chamber, however with the passage being a tight 900mm and no guarantee of the pipe running centrally in the passage (until I dig it up) I'm wondering at alternatives to achieving compliance.

What I'd like to propose instead is a saddle joint onto the clay with a ramped rodding point and further access in the garage. Do you think this would be OK?

Some pictures. Firstly view of manhole facing back garden (high level plastic pipe is sink drain):
View media item 45121Now facing shared passage:
View media item 45122Looking up the passage towards the drives. Connection is proposed under roughly where the dryer vent is. There is a second manhole on the foot of the neighbour's drive, but I haven't opened it:
View media item 45123Same location, but back towards the open manhole:
View media item 45124Layout of the above. Red is proposed:
View media item 45125Cross-section of the proposed route. I haven't drawn the saddle itself. I've added a standard 450mm access chamber in grey just to show how tight it is:
View media item 45126
Many thanks

 

[Hugh Jaleak]

I wouldnt want to try an squeeze a chamber into that space....

You wont saddle onto a 6" pipe, you'll need to insert a 6" junction with a 4" branch, then provide access elsewhere. Bringing the soil pipe from the pan into a stub stack in the garage with an access cap, then running straight under the floor to the drain may be ok, but bear in mind this work is notifiable under building regulations and final decision will be with B.C.O. as to access provision and connection to existing drain.

Looking at the construction of the existing manholes it's a good chance the drains are vitrified clay, not salt glazed. (Slight difference in O.D. of pipes and jointing techniques.)

 

[mfarrow]

OK thanks Hugh.

This is what I was thinking of using: http://www.flexseal.co.uk/uploads/docs/pdfs/TA_Saddle_DataSheet.pdf
Any different to what you've seen/used to?

I did think that drilling a 127mm hole into a pipe only 180mm ish wide would be a little tight, but I wanted to avoid as far as possible any source of muckiness associated with going into a shared drain.

The other thing I wasn't sure about if connecting using a new PVC branch section was how to best do it materials wise. I'm assuming I'll have to connect to the clay using 2 rubber couplings, however that requires a spigot at both ends of the branch, which I haven't seen in any of the catalogs. Could someone please point me in the right direction?

 

[Hugh Jaleak]

I honestly think you'll find it nigh on impossible to cut a hole in a 6" clay pipe to accomodate a 4" connection. Assuming the existing 150mm drain is V.C., i'd cut a small section out, enough to slot in a 'Supersleve' junction.

Supersleve stuff is all plain ended, so a you can use a flexseal either end to slip the junction into the existing run, then the appropriate collar on the 4" branch to couple to plastic.

http://hepworth.wavin.com/master/ma...&middleTemplateName=oc_middle_system_browse_I

 

[mfarrow]

OK that looks like a bob on solution.

I always thought it would be middle of weekday or middle of night connection and should only take 1hr once all prepped & section ready to come out so I'm not overly worried. I could always call on or letter-drop the neighbours asking if they wouldn't flush the loo for a couple of hours - is this the done thing usually?

I've added the clay fitting to my drawing. It pushes the whole thing down by 2 inches but let's hope the pipe is low in the ground. I know I could always go straight through foundation but that doesn't leave much room for an exterior rodding point. I've assumed 20mm per meter from the open manhole, or however many inches per feet that was in 1958!

View media item 45133

 

[Hugh Jaleak]

If on good terms with neighbours i'm sure they'll oblige, otherwise either risk it or plug the outlet from previous manhole with sandbag or stopper. 1:60 is rule of thumb for the fall on 6" pipe, its unlikely to shoot steeply downwards. Any major changes in depth should be done via a backdrop at the next chamber.

B.C.O. may allow you to omit external rodding eye if the drain drops into the existing run from above, provided the horizontal run can be accessed elsewhere. (Vertical unlikely to block.)

 

[mfarrow]

In the end I just risked it, didn't see much point in letter dropping! Worst problem was finding 2 pipes, one on top was for neighbour's storm drain (and washing machine as it turns out).

Outside hole:
View media item 63964 View media item 63965 View media item 63966 View media item 63967 View media item 63968
Garage, passage side:
View media item 63969 View media item 63970 View media item 63971
Garage, house side:
View media item 63972 View media item 63973 View media item 63974
Toilet 'room':
View media item 63975 View media item 63976

 

[Hugh Jaleak]

Washing machine into rainwater pipe is naughty, if water co. find out they could make them alter that.... You've done a good job there, nice one.

 

[ivixor]

Nice job. Lucky that storm pipe wasn't on the other side! What's the vertical pipe after the trap in the garage for?

Interesting position for the extractor fan!

 

[mfarrow]

Thanks both, and thanks for all the advice given pre-construction.

Washing machine ruined a whole evening's work when it released its rinsing content into the trench, 4 times! Each time I mopped up thinking an extra rinse had been set, but 3 days later the neighbour had a new washing machine arrive!

In answer to the questions, extractor fan couldn't really go anywhere else and is ducted under floor where 1/3 of garage will be raised for utility area. Vertical pipe is water mains diverted into garage under boiler and where unvented cylinder should be soon. The pipe's only 1/2" but I've lost a third of its length to increase flowrate.