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Japanese Homes and Termite Control

After demolishing the ceilings, walls, and floors, it’s recommended to implement termite control measures before proceeding to the next phase of the project.

While it’s possible to apply termite extermination or prevention chemicals with the flooring still in place, the work must then be carried out underneath the floor, which is more labor-intensive. Performing termite treatment while the subfloor is exposed is much easier.

Additionally, it’s important to inspect for termite damage while the pillars and beams are still visible after demolition.

A beam damaged by termite infestation.

A cross-section of wood showing evidence of termite damage.

There are said to be more than 20 species of termites in Japan, but the two main species causing the most damage are:

1. Yamato termites (Reticulitermes speratus), found throughout Japan except in Hokkaido.
2. House termites (Coptotermes formosanus), primarily found in warmer regions, such as the coastal areas of the Pacific Ocean and the Seto Inland Sea.

Other termites are endemic to Okinawa and a few other limited areas. Additionally, dry-wood termites (Incisitermes minor), imported from the U.S. and other countries, are also present in Japan and have become problematic.

Yamato termites and house termites are similar in appearance and behavior. In contrast, dry-wood termites, as their name suggests, live in dry wood. Yamato termites and house termites, however, thrive in wet wood or soil, preferring hot, humid environments and being sensitive to dryness.

As a result, in Japan, keeping the subfloor dry is an important measure for termite prevention. Areas like kitchens, bathrooms, and toilets, the shaded north side of a house, spaces beneath the floor close to the ground, and places with leaks are especially prone to termite damage.

Termites are also vulnerable to ultraviolet light because they lack melanin pigments. For this reason, they avoid visible areas, instead creating mud tubes on surfaces such as stones, concrete, and dry wood to move across them. The presence of mud tubes is a clear sign of current or past termite activity and should be addressed promptly.

During the breeding season, termites develop melanin pigmentation and transform into black, winged ants, making them resistant to ultraviolet light. They fly out in search of new nesting partners.

A mud tube that travels from the ground over the surface of the concrete foundation and reaches the wood.

Damage to buildings is often more severe with house termites than with Yamato termites. Yamato termites only consume wood that contains moisture, so they typically affect wood in leaky areas or wood close to the ground (usually less than 1 meter above the ground).

House termites, on the other hand, can carry their own water and soften the wood to feed on it, allowing the damage to extend to higher areas, such as the second floor or even the roof.

Although not as severe as dry-wood termites, termite damage in Japan should not be underestimated. While it may take years for a house to collapse due to termite damage, and the house will not collapse immediately, the loss of wood strength due to erosion poses a serious problem. This weakens the structure and reduces the earthquake resistance of the house.

You can apply termite prevention chemicals on your own, but if you’re dealing with an active infestation and the damage is spreading, it’s better to hire a professional pest control company. Specialized companies have the equipment, like compressors, to inject chemicals deep into the ground and wood.

However, while DIY spraying may cost several tens of thousands of yen, hiring a professional company typically costs several hundred thousand yen.

Keep in mind that some companies may cut corners in less visible areas, so it’s a good idea to be present during the spraying process to ensure the work is done properly.

For a DIY treatment, spray or apply the chemicals under the floor, around the house, and on the wood up to about 1 meter above the ground.

There are various types of chemicals available, including those meant specifically for the ground, those for wood, and those suitable for both, so be sure to check the labels carefully when purchasing.

There are two types of chemicals for termites: prevention and extermination. Choosing the wrong type can lead to further damage. Pyrethroid chemicals, commonly used as insect repellents, are highly repellent and effective for prevention when termites are not present. However, if used when termites are already active, they will avoid the chemicals by moving deeper into the ground or to other areas, which can result in more widespread damage.

If termites are present, or if you’re unsure whether they are, it’s important to select a non-repellent, slow-acting, and propagating agent. Most extermination chemicals are slow-acting, so termites don’t die immediately after exposure. They remain active for a while, and termites that come into contact with the chemical will return to their nests, where they are licked by other termites, spreading the chemical and affecting individuals that were not directly exposed.

Although most termiticides are safe and have low toxicity to humans and mammals, they are not completely harmless. It’s advisable to wear a protective mask and ensure adequate ventilation when spraying. The toxicity is controlled to the extent that it does not harm the human body, but the termiticides currently used in Japan are effective for about five years and need to be reapplied every five years. In some cases, however, their effectiveness may wear off after three to four years. Therefore, it’s recommended to regularly check for termite infestations and take preventive measures as needed.

While termite chemicals are relatively safe for human health, they can have a dramatic impact on insects and fish, potentially causing serious environmental damage if the chemicals seep into waterways. Although it’s often recommended to spray the garden to eliminate termites from the property, it’s important to consider the potential effects on other insects living in the garden.

Spraying termiticides on your own with the floorboards removed involves using a sprayer to apply the chemicals to the ground. For the wood, the chemicals are either brushed on or injected through drilled holes.

When part of an indoor floor is made into a concrete earthen floor, styrofoam may be placed beneath the concrete to improve insulation. However, caution is needed in this case. If regular styrofoam is used instead of termite-resistant insulation, the styrofoam can erode over time and become a breeding ground for termites.