Midori-chan is a patented and revolutionary system designed to maximise vegetation growth and recycle waste, while dramatically minimising water usage. Our engineers at the Kawada Group in Japan developed the system to meet the demands of greener and cleaner communities. Our development of Midori-chan is consistent with our corporate mission of "building a better tomorrow". Kawada's technological innovations have ranged from transportation, energy, information systems, and mechatronics. Now, our future depends on technologies such as Midori-chan, technologies that reduce CO2 and increase vegetation without draining already limited world water resources.

As part of our commitment to corporate social responsibility, Midori-chan was conceived in the late 1990s. Our goal was to recycle building materials and to ease the heat island effect. Our concept is to increase vegetation without wasting a drop of water.

Midori means "green" in the Japanese language. The word "chan" after "Midori" is a nickname given to children in Japanese. Midori-chan is based upon a system in which rainwater is effectively recycled, stored, and supplied to vegetation. The system mimics and improves upon the system of water supply and evaporation that occurs naturally in the earth's surface. Special water retention materials grip water vapour. Soil moisture transfer is generated by thermal energy balance in the soil and facilitated by water storage units. Regenerated charcoal cleanses the water through natural water vapour absorbed through the plant roots.


Midori-chan is a concept utilising the principles of 3R + 1. Reduce, Recycle, Re-use + Respect.

Pre-construction to Post-construction

Pre-construction Within a minimal amount of time, a fully fledged rooftop garden can be achieved Post-construction

Service Flow

  • Effective utilisation of space and limited water resources stimulate opportunities for vegetation growth, improved aesthetics, healthier living, and reduced building / land maintenance costs.
  • Kawada's "Midori-chan" solutions promote responsible choices by capitalising upon evaporating water via the adoption of regenerated charcoal.
  • Creating environmentally friendly systems using recycled materials that exceed the construction industry's increasingly stringent environmental standards.
  • Pursuing opportunities overseas where Kawada technology can effectively be merged with other leading environmentally friendly products / technologies.
  • Effectively providing a "one-stop shop" for all green rooftop services, under Kawada's umbrella, commencing with waterproofing solutions to ongoing maintenance of the plants species.

Service Flow

Comparison with Conventional System

Green Roofs Irrigation Comparison Table

Water consumption comparison

  • Conventional system - 190 litres / m² / month
  • Midori-chan - 0.17 litres / m² / month

System Outline

System Outline

Standard type (34L) Slim type (16L)

System Composition

System Composition

Experience counts...

When designing rooftop greening solutions, as the leading fabricator and erector of major structures in Japan, Kawada realises the importance of understanding the prevailing building's strength, waterproofing / drainage constraints, and the applicable load that a rooftop can bear. Moreover, this experience within Japan's highly seismic environment has led Kawada to ensure that out greening solutions possess the lowest possible load to combat the effects of earthquakes whilst also minimising the volume of steelwork / concrete required for the structure. It has been proven that our recycled reinforced water storage units can bear vehicle loads.
By employing Kawada's services, waterproofing / structural inspections, building soundness appraisals, and structural strengthening works can be secured. Furthermore, operation and maintenance costs are minimised as under normal atmospheric conditions, watering is unnecessary - some of our solutions have not been watered for over five (5) years. Sustainability is achieved via our completely environmentally friendly system that is comprised of fully recycled and recyclable materials.

System Characteristics for Differing Plant Species

  Grass Grass Groundcover Shrubs (small) Shrubs (large) Mid-sized trees
  Slim type Standard type 100 ∼ 500mm 600mm or less 900 ∼ 1,200mm 1,500 ∼ 2,500mm
Vegetation installation examples Slim type Standard type 100 ∼ 500mm 600mm or less 900 ∼ 1,200mm 1,500 ∼ 2,500mm
Plant spacing Complete coverage Complete coverage 200mm intervals 400mm intervals 600mm intervals 1,000mm intervals
Mulch mm - - 50 50 50 50
Soil thickness mm 50 50 100 150 200 250
Regenerated charcoal bags mm 30 30 30 30 30 30
Water storage unit mm 40 70 70 70 70 70
Total thickness mm 120 150 200 250 300 350
Saturated reference weights Without plants kg/m² 69 93 149 200 230 301
With plants kg/m² 84 108 157 210 286 337