Why the treatment follows the construction programme
A termite barrier works only if it is continuous, and on a building site most of the soil that needs treating is reachable for a few days at most. The excavation is open until the blinding is cast, the backfill is loose until it is compacted, and the under-slab soil is exposed until the polythene sheet and the concrete go on. Miss one of those windows and the only way back to that soil is through concrete.
So the job is planned against the programme, not booked as a single visit. Agree at the start how much notice your site engineer will give before each stage, and make sure nobody pours, covers or backfills over a stage until it has been treated and recorded. On a villa the four stages typically fall across several weeks; on a larger building they repeat by zone as the footprint is built out.
