Wooden high-rise construction realized with unique KES construction method and fire-resistant technology
Updated by Shelter Inc. on May 12, 2025, 9:47 AM JST
Shelter Co.
Headquartered in Yamagata City, Yamagata Prefecture, the company develops and manufactures wood structural members based on the three pillars of the KES construction method (joint hardware construction method), COOL WOOD (wooden fire-resistant members for 1, 2, and 3 hours), and FREE WOOD (curved and twisted members). The company also provides design (design and structural design), construction, and renovation of wooden buildings, as well as planning and coordination of wooden urban development, and PFI/PPP proposals.Official Site
The development of "Wooden Cities (R)" is one of the pillars of forestry revitalization, and there are high expectations for its progress from the perspective of reducing greenhouse gas emissions and improving the urban environment by turning cities into "second forests. In the half century since its establishment, Shelter Corporation, a company that researches and designs wood structural members, has consistently been involved in the "foresting the city (R)" business.
Shelter's "Creating Forests in Cities" business is based on a solid foundation that combines the mission of the company's founder, Kazuyoshi Kimura (current Chairman), and the company's proprietary technologies (seeds) that have been nurtured over many years. Wood is an environmentally friendly material that helps combat global warming, and above all, it has the appeal of soothing and warming the hearts of those who live in it," said Kazuyoshi Kimura, the company's current president. Creating an environment in which people can live in mental and physical well-being is the goal of our "Wooden Cities.
Kimura himself is a master carpenter who has been working mainly on wooden houses for generations, and he and his apprentice of the same age have been helping the family business since they were boys. One of the most important skills he has learned is called "chipping," an advanced craftsmanship technique that involves joining two pieces of wood (post and beam, etc.) together using mortise and tenon holes. This is an advanced craftsmanship technique. However, Mr. Kimura had some doubts about this technique.
It takes years to master, and the work can only be done on very simple floor plans and exteriors. There are many parts that need to be cut away from the structure, which weakens the inherent strength of the wood. In fact, joints are considered a weak point in wooden construction, and we thought there must be an easier way to make them stronger.
Taking a hint from a building in Paris that used hardware, he built Japan's first building in 1974 that used hardware for joints. After that, he continued his research and developed the company's original "Kimura Excellent Structure System (KES)" (patented in Japan, the U.S., and Canada), which was put into practical use.
We were convinced that the metal-joining method would be universally recognized when promoting wooden construction. However, in Japan, as in other countries, it is not possible to use steel-frame columns or have the joints exposed. Therefore, we developed a simple yet strong and beautiful-looking method of joining by incorporating our original hardware (connectors) into one member and using drift pins to fasten them to a plate embedded in the other member.
After the construction of the old company building in 1974 using the prototype construction method, the company officially began accepting franchisees in 1988 under the "KES Construction Method. The reason for the large number of franchisees (124 companies from all over Japan) is due to the fact that this technology, which combines versatility and strength, has created a great need.
The biggest turning point was the Great Hanshin-Awaji Earthquake of 1995. At the time, there were 73 houses built by our affiliates in the disaster area, and when our employees and I rushed to Kobe upon hearing the news of the earthquake, we were heartened to see our own KES construction method houses standing firm ......, three stories tall and white, amidst the mountains of rubble that covered the entire area. I was so moved to see our KES construction method house standing there amidst the piles of rubble.
In the Great East Japan Earthquake of 2011, the two-story wooden office building of the Kitakami branch office in Ishinomaki City, Miyagi Prefecture, which was constructed using the KES construction method, escaped collapse when the tsunami hit, completely eliminating concerns about the earthquake resistance of wooden buildings. The earthquake resistance of wooden buildings has been completely eliminated.
In terms of administration and legislation, the Building Standards Law was revised in 2000 to include the installation of metal fittings at joints, and in 2010 the Law for the Promotion of the Use of Wood in Public Buildings, etc. was passed. In 2021, the "Law for the Promotion of Urban Wood Construction" was amended and enacted as a law by the bipartisan "Diet Members Caucus for the Promotion of Urban Wood Construction".
On the other hand, Shelter's "COOL WOOD" (patented), a fire-resistant member consisting of a core of wood surrounded by plasterboard and covered with additional wood and other materials, has been certified by the Minister of Land, Infrastructure, Transport and Tourism as fire-resistant for 3 hours. The company's "FREE WOOD," a curved and twisted member made by "bending," "cutting," and "carving" methods, is used to create a variety of designs.
The design concept based on structural calculations is completely different from conventional wooden buildings. Thanks to these efforts, starting this year (2025), the durability of wooden buildings will be evaluated under certain conditions.Allowed to have a service life equal to or greater than that of a concrete buildingThe situation has changed dramatically, including"
The company has actively participated in the Platinum Forest Industry Initiative from the standpoint that "it is consistent with our goal in terms of fixing a large amount of CO2 in the city," and in 2018, the company received the 6th Platinum Grand Prize and Minister of Economy, Trade and Industry Award as a company. As a future goal, the company is also looking into the establishment of JAS standards for lumber and the resulting revitalization of the forestry industry as a whole.
We would like to reform and restructure from a broad perspective, from downstream to midstream, such as lumbering, and upstream, such as growing high-quality logs, by introducing strict grading of lumber processing according to high-precision structural calculations. By doing so, I would like to encourage a cycle of cutting, using, planting, and nurturing the 5.5 billion cubic meters of forest resources that make up 70% of Japan's land area.
Shelter's vision of a "wooden city" will surely become bigger and stronger at last.
■Related Sites
interpoint (interword separation)Started construction of "Okachimachi Project", a 3-story pure wood building in Ameyoko
interpoint (interword separation)Shizuoka Prefecture Mt. Fuji World Heritage Center
interpoint (interword separation)"Shelter, Kazuyoshi Kimura, "Building Wooden Cities Nationwide! ' (Hirofumi Murata, Zaikai Research Institute 2024)
