Connecting detached garage to existing soil stack

[Iamnotarobot]

Afternoon All,

I have a detached garage which I wish to have a waste pipe installed in for a dog grooming bath. The new build house has an internal soil stack in the corner closest to the garage.

Plan is to dig up the garden alongside the garage and run a 6m long soil pipe just under the house foundation and into the existing soil stack before it inverts towards the inspection chamber which is not near the garage.


Question is how deep does the typical soil stack go into the ground before it inverts? Also, if it inverts to soon and I can not get a connection then what are my option?

 

[Hugh Jaleak]

Answer to question is How long is a piece of string? Only way to find out is to dig down and find it, but by the sound of things you would be better to dig down outside the footprint of the house and couple onto the underground drain, not the stack.

You really don't want to be undermining the foundations, and you cannot connect to a stack lower than 450mm above the invert of the tail of the bend at the foot of the stack.

Connect to the drain with a suitable method, (junction or inspection chamber, you will need to notify Building Control at the local Council, so they will advise what is required), then run in a straight line to your garage, and fit a bottle gulley or stub stack for the waste to discharge into.

 

[Iamnotarobot]

Does anyone know why you cannot connect 450mm to the tail? Interested in the logic of it.?

 

[Hugh Jaleak]

The 450mm rule applies to buildings of up to 3 storeys, higher buildings, and that distance needs to be increased. Theory is, waste falling from above will compress the air underneath as it travels, and to prevent this slight increase in pressure blowing out traps etc, the regs prohibit connections in that bottom 450mm section.

 

[ianmcd]

wait till you see the regulations regarding the water supply to taps ,showers etc for pet washing you might change your mind