Why Pests Still Reach the Twentieth Floor

People who move to a high floor often expect to be above the problem, and are surprised to find cockroaches in the kitchen of a twenty-fifth floor apartment. Height offers almost no protection, because insects do not climb the outside of the building. They travel inside it.

Service risers and drain stacks

Every apartment in a stack shares vertical services: water supply, waste pipes, electrical risers, and in many towers a refuse chute. These run floor to floor in enclosed shafts that are warm, undisturbed and rarely inspected. They are the main route, and they work in both directions.

This is why a treatment applied to one apartment alone often fails. The population is in the shared shaft, and the treated unit is repopulated from it within weeks.

The refuse chute

A chute is a vertical duct connecting every floor to a warm room full of food waste. Where the chute door on a floor does not seal, or where residents leave bags beside the chute instead of putting them in, the corridor becomes an extension of the refuse room.

Rodents use the same route. A rat in a chute has a protected climb with food at the bottom and access at every level.

Lifts, trolleys and deliveries

• Cardboard boxes delivered daily and left in corridors
• The building trolley, which goes from the loading bay to apartment doors
• Food deliveries carried up in insulated bags
• Furniture and appliances brought in through the service lift

None of these is avoidable. They are simply the reason that a tower is not a sealed environment, however new it is.

What actually protects a high-floor unit

Three things, in order of effect. Seal the openings into your unit — the gaps around pipes under the sink and behind the washing machine, and the gap under the entrance and service doors. Keep the floor gullies filled so the drain seal holds. And do not store cardboard.

Those three cost almost nothing and remove most of the routes. Everything else is management of the shared spaces, which is not yours to control.

When to involve the building

If you and your immediate neighbours are seeing the same species at the same time, the problem is in the shared services rather than in any one apartment, and treating individual units will not resolve it. That is the point to raise it with management in writing, with dates and photographs, and ask what the building's programme covers.

Buildings respond much faster to several documented reports from one stack than to a single complaint.

What a building programme normally covers, and what it does not

Most towers in Ho Chi Minh City treat common areas: the basement, refuse rooms, plant rooms, lobbies and sometimes corridors. Very few treat inside private units unless the resident arranges it, and fewer still treat inside the risers and drainage stacks where the population actually lives.

That gap is the reason a well-managed building can still have unhappy residents. The programme is real, and it is aimed at the wrong volume.

The stack pattern, and how to recognise it

• The same species appears in several units vertically above one another
• Activity is concentrated in bathrooms and kitchens rather than living areas
• Insects appear at night and in ones and twos rather than in numbers
• Treatments work for four to six weeks and then fail
• Neighbours report the same timing

Five out of five means the problem is in the shared services. One or two means it is probably in the unit.

What to ask the building for

Ask three specific things: whether the risers and drainage stacks are included in the programme, how often refuse rooms are treated, and whether the chute doors on each floor seal. All three are answerable, and the answers usually explain the pattern.

Put it in writing with dates and photographs and, where possible, with two or three neighbours signing the same note. Buildings act on a documented pattern far faster than on a single complaint, because a pattern is a maintenance issue and a complaint is an individual.

New buildings are not exempt

A tower completed last year has the same vertical services as one completed twenty years ago, and it has something an older building does not: an ongoing fit-out programme. Units being finished floor by floor means open risers, unsealed penetrations, construction waste and food brought in by workers.

This is why residents moving into a new development are often surprised to have problems in the first year and to find them settle later. The building is not defective; it is unfinished, and the routes close as the fit-out completes.

During that period the sensible response is exclusion at your own front door rather than repeated treatment inside the unit.

What to check the week you move in

The first week is the only time the unit is empty enough to look at properly. Open every cabinet, look at the back corners, check the pipe penetrations under the sink and behind the washing machine, and look into every floor gully.

Anything that needs sealing is a twenty-minute job with wire wool and sealant while the kitchen is empty, and a much larger job once it is full. The same applies to a door sweep: fitting one before the furniture arrives takes ten minutes.

Global Pest Control is the English-language arm of Khử Trùng Toàn Cầu. The same technicians and the same programmes are described on the Vietnamese version of these service pages.

Book an inspection

Site inspections are free of charge and carry no obligation. A technician walks the property, identifies the species and the harbourage, and sends a written quotation with the method and the schedule — normally within one working day.

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