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耐震性能
Earthquake resistance
Every construction method we offer is engineered for earthquake resistance, with options to go further.
Seismic grades, explained
Japan defines three seismic grades. Grade 1 meets the minimum building-code standard. Grade 2 is the standard required for long-term-quality-housing certification. Grade 3, the highest grade, is built to the same standard used for disaster-response facilities such as fire and police stations.
Meets the minimum building-code standard.
Built to withstand 1.25 times the force required for grade 1.
Built to the same standard used for disaster-response facilities such as fire and police stations.
Three construction methods, all engineered for it
Wood post-and-beam construction, reinforced-concrete (RC) construction, and platform-frame construction are all designed against a defined seismic standard, whichever method fits your plan.
Wood post-and-beam construction
Traditional Japanese-style construction reinforced with diagonal bracing, structural plywood, and hardware connections, on a mat foundation.
- Load-bearing walls using diagonal bracing and structural plywood
- A mat foundation for solid support from the ground up
- Structural calculation available as an option, for a detailed engineering check of the forces on the building
Reinforced-concrete (RC) construction
High strength and durability from reinforced concrete. Few local builders in this area can take on RC construction, so it's a distinctive option we offer.
- High strength and durability from reinforced concrete
- A structure that also stands up well to typhoons and fire
- Few local builders offer RC construction — a distinctive strength of ours
Platform-frame construction
A box-like structure where the walls, floor, and roof act as a single unit, spreading earthquake force across the whole building.
- Supported by panels, not just posts — strong against earthquakes
- Also delivers strong insulation performance
- A method with a long track record in North America
Seismic dampers
A seismic damper is an optional device that absorbs earthquake energy and reduces how much the building shakes, which helps with repeated aftershocks as well as the initial quake.
Retrofitting an older home
Homes built before the current seismic code took effect, decades ago, may not meet today's standard. We offer a seismic diagnosis first, followed by retrofit work such as added bracing or foundation reinforcement if needed.
Sasebo City runs a subsidy program for seismic diagnosis and retrofit of qualifying older wood homes. Eligibility depends on the building's age and condition, so we confirm the details with you directly.
Why it matters financially
Grade 3 can reduce your earthquake insurance premium, and grade 2 or higher is required for long-term-quality-housing certification, which can open up tax benefits covered on our financing guide page.
See our financing guide →Every method we offer is engineered for earthquake resistance
A licensed engineer talks through the options directly with you, so you can weigh budget and performance in the same conversation.
Frequently asked questions
Do I need seismic grade 3?
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The building code minimum is grade 1. Grade 3 is engineered to withstand 1.5 times the force of grade 1, to the same standard used for fire and police stations, and it can also reduce your earthquake insurance premium. We help you weigh the cost against the peace of mind.
What is a seismic damper?
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A seismic damper absorbs earthquake energy and reduces how much the building shakes. Where seismic-resistant construction is built to withstand the force, a damper absorbs it, which also helps with repeated aftershocks.
Can a wood-frame home reach grade 3?
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Yes. With a structural calculation and the right wall placement, hardware, and foundation design, wood post-and-beam construction can reach grade 3 as well. We offer this for both wood-frame and RC construction.
Contracts and the legally required disclosure statement are prepared in Japanese only.
Talk to us about your home
We can walk you through the process in plain language. Send us a message using the contact form.