Risk Dictionary › シロアリ

Termite Damage / Infestation

---

What it means

シロアリ (termites) are a serious structural threat to wooden buildings in Japan. Yamato termites (ヤマトシロアリ) and the more aggressive Formosan termites (イエシロアリ) are common across the country, particularly in humid areas and older buildings.

On a disclosure form, シロアリ may appear as シロアリの被害あり (damage confirmed), 過去に被害あり (past damage), シロアリ駆除実施済み (treatment completed), or 不明 (unknown). Each requires a different level of investigation.

Why it matters

• Structural integrity — termites eat wood from the inside out. Damage is invisible until it is severe. Floor joists, wall studs, and foundation sill plates are primary targets.
• Often co-occurs with 雨漏り — damp, water-damaged wood is the most attractive environment for termites. The two problems frequently appear together.
• Treatment cost — professional treatment (駆除) typically costs ¥100,000–300,000 for a standard house. If structural repair is needed, costs can exceed ¥1M.
• Treatment warranties — reputable treatment companies issue 5-year warranties. If treatment was done, check whether the warranty is still valid and transferable to a new owner.
• Older buildings and akiya are higher risk — properties that have been vacant, poorly ventilated, or left unmaintained are significantly more likely to have termite activity.

What to confirm before buying

1. Has professional termite treatment (シロアリ駆除) been carried out? If so, when and by which company? Is a warranty in place?
2. Commission a home inspection that specifically includes the underfloor space (床下) and roof space (天井裏).
3. Check for visible signs: mud tubes along foundation walls, hollow-sounding wood when tapped, fine sawdust near wooden elements, soft or spongy floors.
4. Is 雨漏り (water leakage) also present? These two issues compound each other.

Questions to ask the agent (Japanese)

Official source

Sellers must disclose known シロアリ damage in the 物件状況等報告書. The公益社団法人 日本しろあり対策協会 (Japan Termite Control Association) certifies treatment companies and issues industry-standard warranties. Home inspection including underfloor space is performed by 既存住宅状況調査技術者.

Related terms