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SMB Kenzai delivers added value and supports building construction from many angles

Updated April 2017

Environment-friendly wooden buildings

Wooden houses that are built in the traditional Japanese architectural style are popular for the feel, warmth and smell of their wood. More than that, wooden houses offer many other advantages, including excellent heat insulation and humidity control, as well as deodorizing and disinfecting effects, and are also environmentally superior. That's why wooden houses have been making a come-back in recent years. In October 2010, the Japanese government established the Act on the Promotion of the Utilization of Wood in Public Buildings, boosting the trend toward using timber materials for public facilities such as schools and libraries in addition to houses.

In particular, the Summit HR (Holz Ramen) Construction System developed by SMB Kenzai, a subsidiary of Sumitomo Corporation, is attracting much attention.

The office at Ashoro Town Hall in Ashoro-gun, Hokkaido, which was built with the Summit HR Construction System. It features larch from the town's forests as well as a wide opening and large space without braces (posts placed crosswise to reinforce the building)

Summit HR Construction System―pioneer in applying the GIR(*) method to medium- to large-scale wood construction

The Summit HR Construction System, which was uniquely developed by SMB Kenzai, features unexposed joints and high strength. To ensure that posts and beams can support the entire load, the system employs the same method used in reinforced concrete structures. With this system, wood can be used to achieve wide openings and large open spaces in buildings with no partitions, such as gymnasiums, which require an adequately strong structure.

The above strength is enabled by two factors. The first is adopting laminated wood (engineered wood), a type of wood that is processed in factories off-site, and has the superior strength and stability required of industrial products while maintaining wood's advantageous properties, including heat insulation, humidity control, and sound absorption. The second is strong joints achieved by posts and beams made of laminated wood, and reinforced with steel rods passing through and hardened with epoxy resin. The metal joints are not exposed, allowing the warmth of wood to be fully revealed, which is also effective at preventing salt corrosion. This construction system conforms with the latest Building Standards Act, as its delivery of sufficient strength has been proven by tests conducted by various research institutes. It has actually been adopted in building a number of government offices that serve as regional emergency response centers. The performance has been demonstrated by a case widely reported via construction industry websites: a factory in Ishinomaki City, Miyagi Prefecture, which was built with the Summit HR Construction System withstood the Great East Japan Earthquake and ensuing tsunami.

* GIR: Glued-in-rod (joint system using a steel rod and adhesive for timber structure)

Close-up of a joint of the Summit HR Construction System. The joint is reinforced with rods that pass through and is hardened with epoxy resin

Medium- to large-scale wood construction projects increasing

The Summit HR Construction System also enables "local production for local consumption." For example, sugi (Japanese cedar) is an endemic species in Japan and is widely planted as a resource, but it does not have sufficient strength to be used in large buildings. However, laminated wood can be made from such wood that lacks strength and timber from forest-thinning, thus expanding the potential of domestic wood.

Many medium- to large-scale wood construction projects are planned for public facilities, such as government offices, gymnasiums, and school and kindergarten buildings. Recently, these projects have been expanding to the private sector. Such examples include company buildings using locally produced timber from sugi and karamatsu (Japanese larch) to provide a symbol of the community.

In addition, the Summit HR Construction System is implemented on site at every stage of a building project, from design to the procurement of materials and construction management. This enables the use of local resources for processing and construction. The system has received praise for the design qualities of products utilizing the features of wood, and has been adopted to construct many private facilities as well as public facilities. To date, a total of more than 900 buildings across the country have been built using this system.

For part of these projects, the company has won a host of awards, including the Minister of Land, Infrastructure, Transport and Tourism award for public buildings, living facilities category (Seki Junior High School, Kameyama City, Mie Prefecture); the Japan Council for Advancement of Timber Utilization President award for excellent wooden facilities (Nanporo-cho town swimming pool, Hokkaido); and special award for timber utilization in the Timber Utilization Competition (Matsuo Interchange Center Senshin Building, Chiba Prefecture).

Seki Junior High School, Kameyama City, Mie Prefecture, received the Minister of Land, Infrastructure, Transport and Tourism award for public buildings, living facilities category (in 2016). The multipurpose hall has been designed to be reminiscent of streets in an Edo era post station and built using timber from local sugi forests. A favorite place of the students

From distribution to "functional business"

SMB Kenzai handles not only the construction work of the Summit HR Construction System, but also all kinds of building materials and timber products for the residential housing sector, ranging from interior and exterior decorative materials such as flooring and exterior walls, to equipment systems and appliances for kitchens, toilets and bathrooms. In addition, the company focuses on developing human resources so that every stage of a building project from design to construction will be implemented on its own, and encourages employees to acquire relevant qualifications. Such qualified employees, particularly accredited structural engineers or construction management engineers, play a key role in the construction of offices and ordinary houses, including the exterior walls and interior finishing work.

Recording studio at J:COM Shonan (Kanagawa Prefecture) whose design and interior finishing work was undertaken by SMB Kenzai. This is an example of our functional business adding value to our existing business: we propose designs and constructions to meet individual needs, including sound insulating equipment and lighting configuration

Socially valuable business

SMB Kenzai has been dealing with environment-friendly products for a long time. For example, its unique products are made from gum trees that have been tapped and discarded (Vietnam). The company has also invested in the business of particle boards made from recovered construction waste (Japan).

In recent years, "zero-energy housing" and "smart house" projects have been increasingly drawing attention. In view of this trend, the company has started to offer solar power systems, home energy management system (HEMS) plans, storage batteries and other energy-saving products. It has also launched a pre-cut wood exterior wall materials business aimed at improved building site conditions, shortened the construction period and simplifying the construction process.

SMB Kenzai was established in January 2017 through the merger of Sumisho & Mitsuibussan Kenzai and Marubeni Building Materials. Fully leveraging the benefits from corporate integration, such as the mutual synergy effect and increased earnings power, the new enterprise is working to achieve further growth as a leading building and housing materials supplier in Japan. The company, anticipating future changes in market trends, will consistently take on challenges to contribute to wider society through services to the building and housing industry.

SMB Kenzai produces laminated wood in Vietnam using gum trees whose latex (the sap from which gum is made) has been taken. SMB Kenzai is also actively promoting the effective use of resources

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