How to Get Rid of Cockroaches in a Greenwich Property

Why Spraying Makes It Worse

This is not a sales argument for calling somebody. It is a description of insect behaviour, and it applies whether the spray is applied by you or by a contractor who should know better.

A residual surface spray applied across a kitchen kills the insects it contacts. What it does to the rest is push them deeper - a response known as dispersal. German cockroaches move away from the treated surfaces into voids the spray never reaches: further inside unit carcasses, deeper into the cavity around cabling, into the boxed pipework, and in a block, into the riser and towards the neighbouring flat.

The kitchen looks better for a week or two. The population is now distributed across more of the building, in places that are harder to treat, and the job that eventually gets done is bigger than the one that would have been done first time.

The visible improvement and the actual outcome point in opposite directions, which is why this mistake is so easy to make twice.

What Gel Bait Does Instead

Bait works the other way round. It is placed at and around the harbourage rather than across open surfaces, and it is taken back into the void by the insects themselves.

That reaches the part of the population that was never going to walk across a treated worktop - which, in an established German cockroach infestation, is most of it. It also means the treatment does not push anything anywhere, so the problem stays where it is while it is dealt with.

The Preparation That Actually Helps

Two things, and one of them is the opposite of what people assume.

Do: clear access to the harbourage

Pull out the fridge, the washing machine and the dishwasher if you can, and empty the base units. The treatment can only go where somebody can reach, and the difference between a kitchen where the appliances have been pulled out and one where they have not is a real difference in how much of the population is reached.

Do not: deep clean the day before

It feels like the responsible thing and it works against you. A deep clean immediately before the visit moves the population without reducing it, disturbs the harbourage so the evidence is harder to read, and removes the droppings and smear marks that show where the runs are.

Clear the access, leave the grime.

What Happens on the Visit

1. Species identification. German or Oriental, because it decides whether the work is in the kitchen or at the drain.
2. Harbourage survey. Behind and under appliances, inside unit carcasses, the underside of worktops, pipe entries, the warm cavity around motors and cabling. For Oriental, the drains, gullies, bin store and basement.
3. Treatment at the harbourage and along the runs between them. Not a general spray of a room.
4. An account of what was found, including whether the evidence suggests the population extends beyond your property.

Why There Is Always a Follow-Up

Egg cases are protective capsules. A treatment that dealt with every live insect on the day still leaves whatever is inside them, and they hatch afterwards.

So the second visit is standard for cockroach work rather than a sign of failure, and it is timed for what emerges after the first. A cockroach treatment sold as a single visit is optimistic rather than complete, and it is worth checking whether a competing quote includes the return.

Between the Two Visits

• Leave the treated areas alone. Do not scrub behind or under the appliances. Cleaning removes the treatment along with the mess.
• Expect to keep seeing them. Activity between visits is normal. What matters is the trend.
• Do not spray anything. At this stage a retail spray disperses the population the follow-up is about to reach.
• Keep the appliances accessible if they were pulled out - it saves time and improves coverage on the second visit.
• Raise it with neighbours or the managing agent now if there is any suggestion the population is building-wide. Acting on that at the follow-up is far better than discovering it two treatments later.

In a Block: When One Flat Is the Wrong Unit

German cockroaches move between flats through service risers, boxed pipework and the gaps around waste pipes. An infestation reported in one flat may have been established in the building for a long time.

Twelve separate flat treatments in a block with an infested riser is twelve times the cost for a result that cannot hold. One building-wide instruction through the managing agent is a different and far better piece of work, and we will tell you which situation you are in rather than take the booking twelve times.

For Oriental Cockroach, the Work Is Somewhere Else

If the survey points at drains, gullies, a bin store or a basement, that is where the treatment goes - and where the maintenance goes afterwards. Damaged gully covers, an open inspection chamber, standing water and food waste stored at ground level all keep a population supplied.

Where the origin is a defective drain rather than a housekeeping matter, that is a drainage repair and we will say so rather than treat the kitchen again.

What Good Looks Like at Each Stage

So you can tell whether a job is going correctly rather than guessing.

1. At the survey: somebody identifies the species and looks behind and under the appliances rather than glancing round the room. If nobody moves the fridge, that is a warning sign.
2. Immediately after the first visit: activity continues. This is normal. Insects emerging from harbourage and encountering the treatment is the mechanism, not a failure.
3. Over the following week or two: numbers falling, and dead insects appearing in the open - which is what people find alarming and is actually the clearest evidence of progress.
4. At the follow-up: the second visit deals with what has hatched from the egg cases. Expect the harbourage to be checked again rather than the same treatment simply repeated.
5. Afterwards: a genuine drop to nothing, sustained. If activity holds steady after the follow-up, something is not being reached - and in a flat that is very often the building rather than your kitchen.