GSB and soiling are not the same pile

Soiling is selected material for filling and site preparation. It makes a level. It is not the layer a road specification is talking about when it says granular sub-base.

GSB is graded to sit and compact under the next course. It is booked as road stone, with the stretch and the layer named, not as a substitute for 20 mm in a slab and not as a cheaper word for soiling.

If both are going to the same site, they are still two lines on the docket. Mixing them in one lorry to “save a trip” is how a layer fails a check the next morning.