Blog circa Highperformance Sheathing Boosts Earthquake Resistance in Wooden Homes

When an earthquake strikes and buildings begin to shake violently, what concerns people most after personal safety? The structural integrity of their homes becomes the paramount concern. In Japan, wooden houses have drawn significant attention for their unique construction methods and material selection that enhance earthquake resistance. This article examines the critical seismic-resistant components in wooden construction, particularly focusing on how "Tiger Board" significantly improves a building's overall earthquake resistance.

Wooden Housing Structural Systems: Blending Tradition with Modernity

Approximately 90% of detached houses in Japan use wooden construction, with the "wooden post-and-beam method" (also called traditional Japanese construction) accounting for 80% of the market. This traditional building technique forms the main framework of houses using vertical posts and horizontal beams, reinforced with diagonal "bracing" (supporting timber).

To further enhance earthquake resistance, some builders have introduced the "wooden post-and-beam panel construction method," which incorporates "structural sheathing" into the framework. This hybrid approach combines the flexibility of traditional methods with the seismic advantages of panel construction.

Structural Sheathing: The Key to Earthquake Resistance

While traditional wooden post-and-beam construction can withstand vertical loads, it shows vulnerability against horizontal forces like those generated by earthquakes. Although adding bracing improves structural stability, this approach has limitations. Structural sheathing transforms point-based stress into surface-based stress distribution, effectively dispersing seismic impact and significantly improving a building's earthquake resistance.

Another common wooden construction method is "2×4" (platform framing), which uses prefabricated wooden frame walls to create a monocoque structure with good seismic performance. However, this method imposes certain limitations on wall layout and interior space design. The "wooden post-and-beam panel construction method" emerged as an ideal solution, combining the flexibility of traditional methods with the seismic performance of panel construction - with structural sheathing serving as its critical component.

Types of Structural Sheathing: Material Determines Performance

Wood-Based Structural Sheathing

Common types include structural plywood, medium-density fiberboard (MDF), and oriented strand board (OSB). These materials offer advantages like lower cost, lighter weight, and easier installation. However, wood-based panels made from wood chips or fragments bonded with adhesive under heat and pressure may contain higher chemical content, exhibit poor breathability, and demonstrate limitations in fire resistance and waterproofing.

Inorganic-Based Structural Sheathing

The "Tiger Board" used by some builders represents inorganic-based structural sheathing. Made primarily from gypsum, this natural, eco-friendly material offers superior fire resistance and breathability compared to wood-based alternatives. The "Tiger EX Hyper" variant, specifically optimized for exterior wall substrates, provides high waterproofing, anti-mold properties, and requires no anti-termite treatment, making it an exceptional structural sheathing material.

"Tiger EX Hyper": The Benchmark for High-Performance Structural Sheathing

Among the "Tiger Board" product line, "Tiger EX Hyper" stands out as one of the most suitable structural sheathing materials for wooden post-and-beam panel construction. Its key features include:

Exceptional Fire Resistance

Composed of gypsum, "Tiger EX Hyper" meets Japan's Building Standards Law requirements for quasi-noncombustible materials. In fire conditions, the material effectively prevents flame spread. Gypsum contains crystalline water that releases steam at high temperatures, functioning similarly to a sprinkler system to lower temperatures. Additionally, gypsum produces no smoke or toxic gases when burning, providing valuable time for evacuation.

Superior Moisture Permeability

The material's excellent moisture permeability makes it particularly valuable for wooden construction, where moisture represents the greatest threat. Condensation within walls can lead to termite infestation and wood rot, significantly compromising structural safety and longevity. "Tiger EX Hyper" demonstrates moisture permeability approximately 12 times greater than wood-based materials, six times that of cement-based materials, and about double that of other inorganic materials, effectively preventing internal wall condensation and extending building lifespan.

Excellent Dimensional Stability

The material maintains remarkable dimensional stability with minimal impact from temperature and humidity changes. This characteristic allows tight panel joints during construction, preventing warping or gaps. Tight joints effectively block indoor-outdoor air flow, improving a building's airtightness and sound insulation.

"Tiger Board": An Environmentally Sustainable Choice

Beyond enhancing earthquake resistance, "Tiger Board" represents an environmentally friendly product. Its primary ingredients - gypsum and paper - include about 50% "by-product gypsum" (chemical gypsum) from sources like thermal power plants. The product also utilizes "natural gypsum" and "waste gypsum" from construction sites, reducing waste generation. The paper component primarily comes from recycled newspapers, magazines, and cardboard, helping conserve forest resources.

Conclusion: High-Performance Materials for Safe, Comfortable Homes

The selection of high-performance structural sheathing like "Tiger EX Hyper" significantly improves a building's earthquake resistance while providing exceptional fire protection and moisture control. These advanced materials form the foundation for constructing safe, comfortable, and healthy wooden homes that meet modern living standards.