Soil Pipe and New Connections

[onabudget]

Hi just looking for some advice on the following please

I have a downstairs bathroom and the soil pipe itself has no vented stack pipe if that's the correct thing to call it.

The current arrangement is a clay soil pipe (I'm at the bottom of the drain in the street so it has about 4 or 5 sections or clay going vetically down right behind the toilet then curves out into the back garden and into the mail drain gulley type thing.

The soil pipe had been leaking and on checking it, the rubber adapter that was stuck in the top of the clay collar had split the clay pipe, so I have dug down to the next collar which is cemented in and using my angle grinder I was going to cut away the damaged section hopefully leaving the next clay section and collar undamaged. I was then going to get an adapter to do clay to plastic and put a new foot or so of plastic in and pack with pea shingle to hold staight then connect toilet back to the top.

I would like to put an on-suite upstairs if I can and need an addtional soil pipe connection. Is it allowed to put a T section adapter in as the top section replaceing the broken clay section and the feed the onsuite at a later data into that. The problem that I can see is that it's below the floor level but the drain is actually about 5 feet down under that.

Can you give me some thoughts please? am I allowed to connect both toilets to the same soil pipe?

the other way I consider was scrap the soil pipe inside and dig down outside and remove the old clay pipe then add plastic right into the main sewer but this a lot more work, or leave the current arrangement as it just adding a small bit of plastic to connect the toiler back up and dig down say a foot outside break into the inspection chamber (on my land) and put a tumbler in?

thanks

 

[Hugh Jaleak]

New stack will need new drain and connection to manhole. I'd repair existing pipe to W.C. as you describe, then install a new section of 110mm from manhole to proposed stack position. You'll need a 'rest bend' at the foot of the stack.

 

[onabudget]

thanks for that - I read that the rest bend needs to be min 45 cm from the nearest connection but max 1.5 m from the closest pan, why is the max set at 1.5, is this just to reduce the smack as it's hits the rest bend?

when I run a separate waste for the on-suite is there any regs that govern how far in terms of depth the tumbler must be from the top, the total depth from lid to bottom is about 1.4 meters and the existing pipe is right at the bottom and I was thinking about bringing this one out mid way, I'm guessing in this instance the 450mm minimum does not apply as the nearest connection to the soil pipe will be upstairs so how far do I need to dig the pipe down to be reasonable?

when working out the route to the inspection chamber does the new soil pipe have to enter in the flow side if that makes sense, i.e. the flow through the chamber goes one way along the houses, my house joins at a 90 degree to the flow, and I'm guessing that I need to be betweeb 0 and 90 for the new pipe ? is that right or can I tumble in from the other side?

do you use a 90 degree bend to tumble it in or something less than that?

thanks

 

[Hugh Jaleak]

The 1.5m rule applies when a W.C. is connected directly to the drain. Dont worry about this with a stack, the stack will be vented at the top and you'll never get less than 1.5m between bend and a W.C. on the 1st floor! The 450mm from bend to nearest connection is (IIRC) to prevent the pressure from falling waste and water in the stack 'blowing out' any traps on sinks etc.

New drain wants to be a sensible depth for protection (e.g. in case it gets hit with a spade) if its too close to the surface (usually because it cannot be avoided) then protection with concrete is required. I'd aim to get it a min of 600mm below the surface.

Fit a backdrop outside the manhole where you wish to connect, use a 'T' at the top (carry on horizontal section into the manhole to provide rodding access along the new run), and 90deg bend at bottom. This wants to be angled to direct incoming waste into the direction of flow through the chamber. Position it as low as you can into the channel, you need to avoid the incoming flow fouling the benching on the opposite side of the manhole. For further info there's some good info and diagrams at http://www.pavingexpert.com/drain05.htm