In Japan, modular building methods have increased in popularity as they are a solution to the challenges of urbanisation.
manufactures and sells timber, glulam and other wood materials for construction. It also provides design assistance, wood structure construction and consulting. Meiken Lamwood sources raw materials primarily from Northern Europe, with Metsä Fibre being a key partner. European red pine, also known as Nordic pine (Pinus sylvestris) , is one of the common types of wood used for traditional post and beam houses in Japan, says Mizuho Matsubara from Meiken Lamwood. Japan is one of the most forested countries in the world, with almost 70 per cent forest coverage. However, domestic species are not always best suited for post and beam construction. According to Matsubara, Nordic pine has specific advantages that make it especially suitable for post and beam structures. “In Japan, the main domestic species used for houses are Japanese cedar (Cryptomeria japonica) and cypress (Charamaecyparis obtusa) . However, the cedar doesn’t have enough strength for beams. On the other hand, cypress has sufficient strength but is not available in the volume we require.” Japanese cedar and Norway spruce (Picea abies) are used mainly for posts, and Douglas fir (Pseudotsuga menziesii) and Nordic pine for the beams. The usage rate of pine is about 40 per cent, Matsubara says. Meiken Lamwood values both the volume and quality of the wood it purchases from Metsä Fibre.
“In my opinion, it’s difficult to improve on the original properties of wood,” she says, referring to both the visual appearance and the strength of the material. Meiken Lamwood used impregnated pine for the exterior walls of their new office building, which was completed in 2020. For this project, the company selected Nordic pine processed with Kebony. This is a type of impregnation with natural substances derived from agricultural waste. The result is a unique dark colour, guaranteed to last at least three decades.
Wood in public architecture
The difficulty in promoting wood usage in urban areas arises from a lack of expertise in wood architecture for commercial buildings. It is also due to the fact that smaller contractors concentrate on residential construction. Meiken Lamwood Corporation is actively working to expand its market share in non-residential building projects. While residential construction drives the demand for wood, non-residential buildings are becoming a crucial market for glued laminated timber, commonly known as glulam. Matsubara says that glulam sales for posts and beams have increased by over 60 per cent in the last 20 years. The Japanese government has been encouraging wood use in public architecture since 2003. Even though Japan has a long tradition of wooden construction, engineered wood products are something new. The term engineered wood refers to construction materials made by bonding layers of wood with adhesives. This process can enhance the strength and stability of the material. Cross-laminated timber, or CLT for short, is a new product that has diversified building methods in urban areas. CLT consists of three or more layers of board glued together crosswise. The structure is fire resistant, strong and stiff, yet lightweight. According to Matsubara, cross-laminated timber has become common in building designs and can be used in most mid and high-rise buildings. “However, since its use is governed by the restrictions on fire-resistant structures in the Building Standards Law of Japan, there are still challenges to its widespread adoption,” she explains. The Building Standards Law of Japan contains strict regulations regarding fire protection. Instead of fully wooden structures, it has become standard practice to use wood in combination with steel or other materials, especially in urban areas. Innovations such as new coating methods and fire- resistant wood materials are therefore eagerly anticipated. •
INNOVATIONS IN JAPANESE WOODEN CONSTRUCTION
Wood in high-rise building construction, combining sustainable practices and advanced engineering. Hybrid buildings that combine wood with other materials such as steel to maximise the benefits of both materials.
Modular building methods
In Japan, modular building methods have increased in popularity as they are a solution to the challenges of urbanisation, population growth in cities and the need for sustainable construction practices. Modular construction also provides a resilient and earthquake-resistant solution. Speed is one of the key advantages of modular building methods. Unlike in Europe, in Japan, prefabricated modules are produced in controlled factory environments. This enables simultaneous on-site preparation and off- site manufacturing. The efficiency of a modular building method is crucial in densely populated urban areas. “Compared to Scandinavia, many urban areas in Japan have very narrow roads. For logistical reasons, assembly has to be as quick as possible, so that building time is reduced to the absolute minimum,” says Takushi Nakashima from Meiken Lamwood. In Japanese architecture, modular building elements are still mainly used in low-rise buildings. Modularisation in mid and high-rise buildings has not yet progressed very far. The image of the modular building method needs renewing, Nakashima admits. Many people do not consider modular building to be a cost-effective choice for residential projects, as it was initially promoted only for non-residential buildings. “It’s seen as a luxury choice, which it shouldn’t be,” says Nakashima.
Using engineered wood products such as CLT.
Modular building techniques that streamline the building process and increase efficiency.
Strong structures
Japan is a country that is constantly seismically active, so it is essential for buildings to be strong. “Nordic pine has excellent strength compared to our domestic species. This is one of its best qualities in the Japanese market,” says Yu Nakashima from Meiken Lamwood. An interesting feature of pine is its rich resin content, which is why Meiken Lamwood often uses it in its original state. Matsubara considers this a good thing.
1 Statista. 2024. Number of dwelling struction starts in Japan from 2014 to 2023, by structure.
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