Tokyo’s first 5-storey wooden structure – an apartment building – is to be built near Shimouma in Setagaya-ku.
Under a revision to the Building Standards Act in 2000, wooden structures over 4 stories are permissible as long as they meet building strength and fire resistant regulations. Prior to this amendment, a law made during the Taisho period (1926 – 1926) limited wooden structures to 3 stories.
Although the amendment was made 12 years ago, it has not been widely taken up by the construction industry. In Tokyo city, just one 4-storey wooden residence was built in Chiyoda-ku in 2011.
The privately developed apartment building is designed by KUS (www.kus.co.jp) and completion is scheduled for April 2013. The building footprint is 92.84 sqm and the total floorspace is 372.60 sqm (4009 sqft). There will be a retail space on the 1st floor, and floors 2 to 5 will be residential. Drywall (or gypsum board) will be used to bring the building’s fire resistance up to code.
This form of construction is also said to be more eco-friendly than concrete or steel-frame buildings. The construction cost, however, is about 20 – 30% higher than reinforced concrete, but is partly covered by subsidies provided by the MLIT to promote the use of wood.
If 4 and 5 story wooden buildings become more popular, construction prices should decrease. For 2 and 3 storey homes, wood is still the cheapest option available.
Source: The Sankei Shimbun, June 19, 2012.