Soil stack pipe into ground level gully

[stonehouse]

Greetings everyone.

I wish to convert one of my property's ground level open gullies (connected to main foul drainage) for external soil stack pipe use but I understand that the base of a soil stack has to be a rest bend, not a trap.

So, if I replace the existing trap with a new rest bend (200mm radius as per Building regs), how should the RW downpipe be connected?

Furthermore, I will need wash basin and bathtub waste pipes to be installed from first floor (currently no bathroom there), so if I put an external wall hopper at first floor level, how should be the base of the hopper downpipe be connected to the drainage?

Advice welcomed. Here are photos of the gully in question:

 

[John D v2.0]

Just dig up the gulley, put in a rest bend at the bottom of the stack and a new gulley under the downpipe, then join them together with a branch into the remaining pipe stub.

 

[John D v2.0]

Furthermore, I will need wash basin and bathtub waste pipes to be installed from first floor (currently no bathroom there), so if I put an external wall hopper at first floor level, how should be the base of the hopper downpipe be connected to the drainage?

Regarding this you can't put open hoppers any more like that, you'd have to either put them into the stack or have a separate 50mm stack to bring them down to the underground drains.

 

[Hugh Jaleak]

Dig out existing gulley, and cut back drain to a suitable point. Fit a junction, (assuming that length of drain is accessible from a manhole downstream, if not you may need to fit a mini chamber instead of a junction), take the branch across to the downpipe position and fit a new trapped gulley to take the rainwater, then continue forward to the proposed stack position, fit your bend and continue up with the stack.

As said above, Hoppers for waste pipes are illegal now under Building Regs unless as a direct replacement. Normal practice is to connect wastes directly to the stack via boss connections.

 

[stonehouse]

Just dig up the gulley, put in a rest bend at the bottom of the stack and a new gulley under the downpipe, then join them together with a branch into the remaining pipe stub.

Thank you.

 

[stonehouse]

Regarding this you can't put open hoppers any more like that, you'd have to either put them into the stack or have a separate 50mm stack to bring them down to the underground drains.

As said above, Hoppers for waste pipes are illegal now under Building Regs unless as a direct replacement. Normal practice is to connect wastes directly to the stack via boss connections.

I don't like the idea of connecting wastes (wash basin and bath) to a soil sack pipe because I imagine sewer smell could come into the building.

A separate 50mm stack sounds good. Should a trap be installed at the base of this 50mm stack?

Thanks.

 

[Hugh Jaleak]

I don't like the idea of connecting wastes (wash basin and bath) to a soil sack pipe because I imagine sewer smell could come into the building.

A separate 50mm stack sounds good. Should a trap be installed at the base of this 50mm stack?

Traps on the appliances will prevent odours coming into the building, deeper seal traps are required when wastes are connected to a stack. Ideally stack needs to be vented so most odours will escape out the top to atmosphere anyway.

If using 50mm to the gulley, traps will still be needed on the appliances, the wastes are then connected into the 50mm pipe rather than the stack.

 

[stonehouse]

Thank you.

By the way, why are hoppers no longer legal?

 

[John D v2.0]

I can only assume hoppers aren't allowed because the drainage system shouldn't have waste water splashing about in the open especially overhead, as it's not really hygienic. However there may be some other technical reason.
It's still acceptable to have air gap situations such as washing machine standpipes but they probably don't splash around.

Not sure if anyone has another suggestion though.

 

[Hugh Jaleak]

Hopper were banned for the simple reason they were unsanitary. Often located right underneath the bathroom window, once coated with the dried up remnants of congealed sop scum, they began to hum in warm weather. Washing Machines pump out at a fair rate, (hence why 40mm pipe must be used to handle the flow), seems the force and flow of the discharge keeps the standpipe fairly clean

Regs changed over the years, at one point soil stacks, (and any ancillary wastes) had to be run internally, with only the vent poking through the roof able to be seen), only for them to be relaxed again and external stacks once again permitted.

Connecting wastes into the stack is common practice now, and has been for around 50 years! Provided the correct traps are used, and the stack vented at the top, you should never have an issue with odours inside the property.

 

[JohnD]

Just dig up the gulley, put in a rest bend at the bottom of the stack and a new gulley under the downpipe, then join them together with a branch into the remaining pipe stub.

You'll probably find the old gulley is cracked and broken anyway, so you can get two jobs done for the price of one.

After you've dug it out, post some pics.