The load travels both ways
On a clearance the material only travels one way. A landscaping build is different, because for every tonne of spoil leaving there is close to a tonne of aggregate, sand or topsoil arriving. A patio job might take out eight cubic metres of soil and bring in MOT Type 1, sharp sand and topsoil, all tipped on the drive by a lorry that cannot get any further.
The dumper does both legs. Sizing it for the outward leg alone is where dumper hire for landscaping projects goes wrong, because the inbound aggregate is heavier per cubic metre than the soil you took out.
Working out the number of trips
Plan against the rated loads rather than the look of the skip. Ten tonnes of material is ten runs on the tracked barrow or the 1 tonne Thwaites, both rated at 1,000kg, and four on the 3 tonne at 3,000kg. On volume the Thwaites holds 500 litres heaped against 1,950 on the 3 tonne, but aggregate and wet soil hit the weight rating long before either skip looks full.
Divide the tonnage by the rated load, then add trips for the awkward parts: the corners the machine cannot reach and the last of the spoil that has to be scraped up. Loading past the rating affects braking, steering and stability, and a landscaping site is full of temporary slopes and soft edges.
