minimum height for soil pipe connection ?

[sm_jamieson]

I want to add a downstairs loo. Is there a minimum height on the vented stack that I can connect to ? If so, what is the height with reference to - the ground level / bottom of sewer etc ? Simon.

[<me9]

450 mm above foot of stack (invert level) if less than 3 storeys.

[sm_jamieson]

Just checked on ODPM, 3 storey can be 450mm, it's over 3 storeys when it must be increased. So if you do a loft conversion, you need no change your downstairs loo connection ! Simon.

[Roger]

The message from contains these words:

Is that just for toilet pan connections or does it also apply to sink wastes as well?

[Tony Bryer]

It's a general rule. Stuff coming down the stack fast tends to bounce when it hits the bottom ... need I say more?

[Roger]

The message from Tony Bryer contains these words:

I asked because I have (have had for 20 years or more) a connection that goes into the soil pipe immediately above the the bend. So far I haven't had a blockage there but I have thought for some time that the situation was less than ideal.

The basic problem is that the main drain reaches the house a foot or more above kitchen floor level so I don't have any room for manoeuvre. The main drain only has a rodding eye in it so it looks as though the only way out would be to construct a shallow manhole at that point and plumb the waste directly to that.