basin waste question - slotted or solid ?

[Colin Wilson]

Why, and what's the difference ?

Slotted wastes appear to have holes in the side - which i'm having trouble figuring out why you'd have them, since they would logically be liable to leak ?!?

Solid

[Autolycus]

Slotted wastes are for basin with the traditional cast-in passage from the overflow.

[Roger Mills]

Indeed. The top flange seals against the inside of the basin, and the bottom rubber washer and nut (plus a liberal dose of Plumbers' Mait) seal against the bottom face. Water running out of the overflow flows through the internal passage and *into* the waste via the slots - and thence on down the drain.

[Colin Wilson]

Thanks for the replies - makes sense now :-}

(i'll have to check out the sink we bought now, see what sort it is !)