kuraray


News Releases 2009

Lightweight, Thin-Layer Rooftop Gardening and Corrugated Plate Roof-Greening System Released
Achieving Rooftop Gardening that Features Superior Energy Conservation Effectiveness, Lightens the Load Placed on Roofs and Provides for Low Maintenance

September 11, 2009
Kuraray Co., Ltd.
(The Kuraray Group)

Kuraray Trading Co., Ltd. (Headquarters: Osaka City, President: Osamu Asaba) announces the release of a lightweight, thin-layer rooftop gardening and corrugated plate roof-greening system on September 16, 2009. This system was developed jointly and will be sold by the eight member companies of the Thin-Layer Rooftop Gardening Research Group. It features reduced load on buildings and superior low-maintenance capabilities.

Limitations on the amount of soil used in order to reduce the load on buildings have been an issue for conventional rooftop gardening systems. This limitation has resulted in increased soil temperatures and, in turn, a greater tendency towards drying. Consequently, regular watering and cleaning was required. This problem has been solved by the thin-layer rooftop gardening and corrugated plate roof-greening system’s potting soil component, thanks to its use of a soil pouch that was recently developed by Kuraray Trading. Featuring a silver-colored surface and lightweight gardening materials with upgraded heat insulation that effectively reflects sunlight, soil pouches can be filled with appropriate amounts of soil and placed on rooftops.

  • * Surface: silver-colored, polyethylene mesh; bottom: white-colored polyester and polyethylene cloth stitched into a pouch shape

The lightweight, thin-layer rooftop gardening and corrugated plate roof-greening system uses high-heat insulation panels with root-damage-resistant sheets (manufactured by Sekisui Plastics Co., Ltd.) and is constructed with a flat surface that is placed over corrugated plate roofs. The mat, filter and soil pouch construction is placed above this to allow for plant growth.

  • * Outdoor tests reveal that there is approximately a six-degree Celsius difference in the surface temperature of soil pouches and the internal temperature of the soil contained within (results of outdoor tests conducted by a university in Hyogo Prefecture). As a result, the soil pouches are able to prevent deterioration of the planting environment caused by high soil temperatures.

Examples of Thin-Layer Rooftop Gardening and Corrugated Plate Roof-Greening System Constructions

The eight companies that jointly developed the thin-layer rooftop gardening and corrugated plate roof-greening system established the Thin-Layer Rooftop Gardening Research Group in 2005 and conducted R&D related to rooftop gardening systems that reduce the load on buildings. Rooftop gardening alleviates the urban “heat-island” phenomenon by offering such benefits as preventing the reflection of sunlight, lessening rainwater drainage, achieving heat insulation that effectively reduces air conditioning costs and providing an area suitable for rest and relaxation. Rooftop gardening is developing into an environmental business field that is expected to be beneficial from a variety of standpoints, including energy conservation, aesthetics and legal considerations.

Key Characteristics of the Thin-Layer Rooftop Gardening and Corrugated Plate Roof-Greening System
  • 1. Beyond the planting of various types of short plants, it is also possible to plant taller shrubs.
  • 2. Set-up is easy because of the closely placed layout of the soil pouches. In addition, owing to 50cm corner lengths and the compact design, these pouches can easily be filled with soil and are simple to carry.
  • 3. These systems require little maintenance, given the fact that the pouch soil is resistant to drying, dust is not easily generated, concern over rainwater drainage is eliminated and weed growth is impeded.
  • 4. High-heat insulation panels with root-damage-resistant sheets provide an effectively high thermal barrier for the garden.
  • 5. Planting is simply a matter of inserting plants in small cuts made by scissors or knives in the soil pouches’ silver-colored surface.
Sales route
Member companies of the Thin-Layer Rooftop Gardening Research Group => construction companies => customers
Sales targets
¥300 million in the initial year (based on the amount charged for installation)

Overview of Kuraray Trading Co., Ltd.

Headquarters 1-12-39 Umeda, Kita-ku, Osaka City (Shin Hankyu Building)
President Osamu Asaba
Capital ¥2.2 billion
Number of employees 321 (as of March 31, 2009)
Business activities A specialized manufacturing trading company of the Kuraray Group that provides a full range of services related to the manufacture and sale of raw materials, textile materials and products. It responds to a diverse array of market needs through comprehensive services that engage in product-related information and the planning and development of distribution and sales systems.

* The Eight Member Companies that Form the Thin-Layer Rooftop Gardening Research Group

Kuraray Trading Co., Ltd.
Location: 1-12-39 Umeda, Kita-ku, Osaka City
AR Center Co., Ltd.
Location: 4-8-5 Koraibashi, Kita-ku, Osaka City
Es-Waternet Co., Ltd.
Location: 2-7-1 Hotaragaike Nishi-machi, Toyonaka City, Osaka Prefecture
Sawada Menko Co., Ltd.
Location: 3-9-10 Nishi-Imajuku Himeji City, Hyogo Prefecture
Seino Kensetsu Co., Ltd.
Location: 1159-8 Miwa, Ibigawa-cho, Ibigawa-gun, Gifu Prefecture
Sekisui Plastics Co., Ltd.
Location: 2-4-4 Nishitenma, Kita-ku, Osaka
Dream World Co., Ltd.
Location: 4-9-22-603 Nishi Nakajima, Yodogawa-ku, Osaka City
Risu Kogyo Co., Ltd.
Location: 4-222 Maedohigashimachi, Kakamigahara City, Gifu Prefecture