Why single-flat treatments fail
German cockroaches travel between units along shared soil stacks, heating ducts, cable runs and the voids behind kitchen units. Treat one flat and the population shifts next door, matures, and returns weeks later — often with the tenant reporting that your treatment 'did not work'.
Run one coordinated round
Survey every unit sharing a service riser, then bait them all in the same week. Include communal areas: bin stores, laundry rooms, meter cupboards, stairwell risers and any basement plant room.
- Bait every pipe and duct entry point in each unit
- Kitchen and bathroom in every flat, not just reported ones
- Communal bin store and refuse chute hinges
- Re-inspect and top up on day 3, then weekly for a month
Records that protect you
Keep a dated sheet per unit: rooms treated, dot count, product batch, monitor trap counts and tenant sign-off. If a complaint reaches environmental health, that log is the difference between a demonstrated programme and an allegation of neglect.
Everything below assumes a professional-strength bait — our heavy infestation bulk kits kits ship with the applicator and placement map referenced here.
What to tell tenants
Ask tenants not to clean or spray over bait dots, to report rising sightings on day 1 as normal, to empty bins nightly and to report leaks and condensation immediately. Most re-infestations trace back to moisture and food debris, not to the bait failing.