New Durability Evaluation System to Boost Wooden Offices & Commercial Buildings in Japan

The Ministry of Land, Infrastructure, Transport and Tourism (MLIT) is set to launch a new third-party durability evaluation system for wooden offices and commercial buildings in fiscal 2025-26. This initiative will focus on waterproof performance, a critical factor in determining the longevity of wooden structures.

If a building meets the designated durability standards, it will be certified for a service life of 50 years or more—more than double the current statutory lifespan for wooden office buildings. This certification is expected to make it easier to secure financing from financial institutions, driving greater adoption of wooden commercial buildings.

Addressing the Lifespan Disparity in Wooden Buildings

Under current regulations, the statutory useful life for wooden office buildings is only 24 years, compared to 50 years for reinforced concrete structures. This shorter depreciation period has been a long-standing concern in the industry, as it limits financial planning and loan eligibility, ultimately hindering the expansion of wooden construction in commercial spaces.

To address this, industry advocates have pushed for policy changes, arguing that well-designed wooden structures can match or exceed the durability of other materials when properly maintained.

How the New Certification System Works

The durability assessment will be conducted by housing performance evaluation agencies authorized by regional development bureaus. These third-party inspectors will examine:

• Waterproofing measures to ensure rainwater does not penetrate the structure
• Preservative treatments or other protective measures applied to exposed areas

If a building passes these inspections, it will qualify for a 50-year certification, making it eligible for long-term financing options and boosting investor confidence in wood-based commercial construction.

A Step Toward Sustainable Building Practices

MLIT’s move to expand wood use in offices and commercial spaces aligns with Japan’s broader strategy to promote carbon sequestration and reduce the environmental impact of construction.

According to an MLIT survey of buildings started in 2011, wood dominates in one- to two-story residential buildings (88.4%) but remains underutilized in non-residential buildings (17.1%). This new evaluation system aims to bridge that gap by making wood a more viable and attractive option for developers and investors alike.

With sustainability at the forefront of construction trends, this certification system could be a game-changer for Japan’s wood industry, paving the way for more durable, eco-friendly, and financeable wooden buildings in the years to come.