What compaction lift thickness should be used for trench backfill?

Lift thickness depends on the compactor's energy output and the soil type, but as a general principle, compacting oversized lifts to save time results in inadequate density at the base of each lift, risking future settlement. Manufacturer guidance and project specifications typically define maximum lift thickness for the compactor class being used. Field density testing should confirm the specified compaction is being achieved rather than relying on visual inspection alone. Sparkline Group advises contractors on compactor selection suited to the lift thicknesses specified in their project documents.