Cockroaches in Flats and Shared Buildings

How they move

The Routes Between Units

A party wall is not a barrier. In a converted or purpose-built block the things that connect flats are exactly the things cockroaches use:

• Service risers carrying waste, water and electrics vertically through the building — the single most important route, and the reason a problem often runs up and down a stack rather than side to side.
• The gaps where pipes pass through floors and walls, which are almost never properly sealed.
• Joist ends and floor voids in a converted house.
• Shared extract ducting.
• Communal corridors, bin stores and laundries.
• Lift shafts and the riser cupboards off them.

None of those are yours, and that is the practical problem.

Photographs on this page are for illustration purposes only.

Why it comes back

A Good Treatment in a Bad Building

The complaint we hear most in blocks is that the treatment worked and then they returned. Usually that is exactly what happened: everything in the treated flat died, and a few weeks later more arrived from an untreated flat through the same penetration they used originally.

It is not a failed treatment and it is not bad luck. It is a treated flat in an untreated building, and no amount of re-treating your own kitchen changes it.

Which is why the most valuable thing you can do is often not to book another treatment. It is to establish whether anyone else in the block has the same problem.

What to ask for

The Conversation With the Agent

Managing agents and freeholders vary enormously in how they respond to this, and a specific ask works better than a general complaint. Worth asking for, in writing:

• Whether any other flat has reported cockroaches, and when.
• An inspection of the communal areas, the bin store and the riser cupboards.
• Sealing of service penetrations between flats, which is usually cheap and is the permanent fix.
• A co-ordinated treatment of the affected flats together rather than one at a time.

A written inspection report helps here, because it turns your opinion into a finding. We can provide one setting out what was found and what the building needs.

Your own side

What Is Worth Doing Anyway

Even where the building is the problem, sealing your own side is worth the money and you can do most of it.

Seal around the waste pipes under the sink and behind the washing machine, and where the soil pipe passes through. Fill the gaps at the back of the kitchen units. Close the gap where the extract duct leaves the wall. Mesh or seal the airbrick if there is one. Check the boxing around the riser in the bathroom, which on a lot of blocks is simply a panel with a hole behind it.

None of it removes a population, and all of it reduces how quickly one arrives back.

Short answers

Cockroach Questions

Going further

Cockroach Guides