Replacing soil pipe and connecting waste gully

[dannyrico]

Broke up an old concrete slab at the side of my house, discovered cracked and dislodged clay connector below iron stub. Had a suspicion, so I kept digging and found another major crack just after the gully branch under the pipe. Both cracks must’ve been there a while as soil had been washed away all around.

My current plan is replace everything with PVC, including cast iron stub. New bend, new straight run, new gully and junction. Connect to first bit of sound clay pipe downstream of current gully junction. 10mm pea gravel/shingle bedding, more gravel to cover pipe, then back will with soil. The final finish desired is gravel with stepping stones.

My questions:
- What are recommended depths? The stack connection to bend and pipe seem pretty shallow, so I'm wondering how high I need to backfill to prevent stress on pipe below?
- What's the best approach to secure a bottle gully in place? Just pea gravel? Cement platform?
- Anything else I'm missing or should be weary of?

Thanks!

 

[Hugh Jaleak]

You're governed by the existing levels, so I'd cut the old pipe off at a suitable point, couple to Plastic and work forward from there. Depends how much work you're happy to do, but I'd give consideration to digging back a bit further if possible, and see if there's provision to fit a Bottle Gully nearer to where the White Waste pipe comes out the building. Look to achieve around a 1:40 fall if possible, although slightly less wont be the end of the world.

When you've decided where to cut the Salt Glazed pipework, run from there in plastic, bedded in peagravel, once happy with the fall, protect with more peagravel, unless you think there may be a risk of damage to the pipework from activity above, in which case some concrete over the top may be need to provide more protection.

I would also look at the possibility of fitting a Mini Chamber at a suitable point before the Stack, and use the side entry to connect a Gully further back, and the drop the Rainwater into that through the back Inlet. Chamber will also give the benefit of access to the system should it be need in future.

Bottle Gully, better sat on a bed of stiff concrete, once happy with position/height, haunch with a little more concrete to hold it in place.

 

[dannyrico]

@Hugh Jaleak Cheers, all great info. You're right about sorting other gullies, might as well do it right while I've got this much dug up.