Many people associate cockroaches with places where they can appear in any kind of home, but some assume they cannot make their way into apartments on higher floors. In reality, cockroaches do appear even in upper-story units. This article explains why cockroaches show up in apartment buildings, how they get in, and which countermeasures are effective.
Where do cockroaches get in from?
Cockroaches enter homes through a range of routes in search of water and food. Understanding the main entry points is the first step in preventing them.
Balcony
Cockroaches can crawl up from the ground and enter via the balcony. Balconies with frequent traffic, such as when hanging laundry, are easy to leave open unintentionally. Cockroaches do not miss even small gaps.
Front door
Cockroaches may also come in through the front door just as people do. They can even crawl along areas near the ceiling and get inside, and the risk is especially high in apartment buildings where the mailbox and door are integrated.
Drain
One of the more troublesome things about cockroaches is that they can also enter through drains. They prefer damp places such as drain openings. Areas with drainage pipes, including the kitchen, bathroom, and around the washing machine, therefore need attention.
Air conditioner duct
They may also enter by following the duct hose that extends from the outdoor air conditioner unit. Because they can squeeze through gaps of just a few centimeters, this is not something to overlook.
Why do cockroaches appear even in apartment buildings?
The main reason cockroaches appear even in apartment buildings is that they can fly. Their movement is generally limited to short distances from higher places to lower ones, but they are said to be able to fly up to around the third floor of a building. The approximate number of sightings per year by floor is as follows.
- Floors 1-5: 3.5 sightings per year on average
- Floors 6-10: 1.2 sightings per year on average
- Floor 11 and above: 0.7 sightings per year on average
The higher the floor, the less often they appear, but the number does not drop to zero. Because cockroaches tend to remain in a place once they find a unit they can enter, early action matters.
Why should cockroach prevention be strengthened in spring?
Cockroach eggs begin to hatch when temperatures rise above 20°C. Taking preventive action in spring before the weather gets hotter can help prevent a major infestation in summer.
- Use a smoke-free fogging insecticide
- Set out poison bait (Black Cap and boric acid balls) or sticky traps
- Repel them with herbs, aromas, or peppermint oil
Households with small children or pets need to be careful about where poison bait is placed.
What are three practical ways to prevent cockroaches?
Completely blocking entry is difficult, but the following three measures can reduce the risk substantially.
Be careful with food waste and food storage
Cockroaches use their strong sense of smell to find food. They are drawn not only to rotting odors, but also to the scent of vegetables such as onions and potatoes and to the fermented smell of beer. Dispose of food waste promptly, and store vegetables in the crisper drawer. Cockroaches also dislike peppermint oil and citrus scents, so spraying those around likely entry points can be effective.
Seal entry routes as much as possible
Physically block entry routes such as gaps around the front door and windows, ventilation fans, and drains. Applying tape or filters to gaps and installing strainers or mesh over drains are effective steps. While referring to the typical cost of pest control, it may also be worth considering a professional pest prevention service as one option.
Use extermination products
Even if you find and eliminate one cockroach, others may still be hiding. A smoke-free fogging insecticide is easy to use in apartment buildings, and it is even more effective when combined with Black Cap or Gokiburi Hoihoi.
Related reading
- How much does pest control typically cost? Fees by insect type, how to choose a provider, and prevention measures explained
- What causes a washing machine drain to smell? Odor countermeasures and cleaning methods explained for rental property owners
- Essential guidance for rental property owners: how bathroom maintenance protects asset value and the basics of caulking repair
Frequently Asked Questions (FAQ)
Q. Do cockroaches not appear on higher floors of apartment buildings?
It cannot be said that they never appear. Even on the 11th floor and above, there are reports of about 0.7 sightings per year on average. That said, the frequency is much lower than on lower floors.
Q. Should cockroach prevention be done before moving in?
Yes. Sealing entry routes and setting poison bait before moving in is the most effective approach. Prevention is less costly and less work than dealing with an issue after you have already started living there.
Q. What scents do cockroaches dislike?
Peppermint oil, lavender, and citrus scents are generally considered unpleasant to cockroaches. Using them in places where cockroaches are likely to enter can provide a repellent effect.
Q. What is the most effective way to prevent cockroaches in apartment buildings?
The most effective approach is a combination of sealing entry routes and placing poison bait. Doing this preventively in early spring can help prevent a major summer infestation.
Q. When do cockroach eggs hatch?
They begin to hatch when temperatures rise above 20°C. In Japan, cockroach activity typically increases from around April to May, so taking action before spring remains important.
