Few pest sightings carry as much unfair stigma as cockroaches — the assumption that they only turn up in dirty homes is widespread, persistent, and simply not accurate, especially in London’s flat-heavy housing stock.

The Real Reason: Shared Building Infrastructure, Not Cleanliness

In blocks of flats and converted period buildings, cockroaches travel through shared walls, pipework, and cavity spaces that connect multiple units. A cockroach doesn’t need your flat specifically to be untidy — it just needs a route in from somewhere in the building where conditions are favourable, which could be several flats away.

This is why cockroach infestations in flats are often traced not to anything within the affected unit, but to a neighbouring property, a shared drain, or a communal refuse area.

What Actually Attracts Cockroaches

• Warmth — consistent indoor heating, particularly near boilers, appliances, or heating pipes
• Moisture — even minimal, like condensation around a sink or a slow drain
• Any accessible food source — this can be as minimal as crumbs behind an appliance or residue on takeaway packaging in the bin, not a generally messy kitchen

Why Flats Specifically Are More Vulnerable Than Houses

Detached and semi-detached houses have fewer shared walls and less connected infrastructure, so an infestation is more likely to genuinely originate within that property. Flats, especially in converted period buildings, share far more structure — which is exactly why a spotless flat next to a neighbouring unit with an active infestation is still at real risk.

What This Means If You’ve Spotted Cockroaches

There’s no need to feel embarrassed or assume it reflects poorly on how you keep your home — professional treatment addresses the actual issue (access points, harbourage sites, and where relevant, coordination with a building’s shared infrastructure) rather than anything related to cleanliness.

What Cleanliness Does Still Affect

To be clear, tidiness isn’t irrelevant to an existing infestation — reducing accessible food sources helps bait work faster and can slow population growth. But it’s not why cockroaches got in to begin with, and a genuinely clean flat can still be affected by a building-wide issue.