屋上緑化の方法（荷重・防水など）

Urban Farm DB summary

This Saitama Prefecture guide on rooftop and wall greening methods cites the Building Standards Act Enforcement Order's live-load table and explains that an existing ordinary house roof can carry roughly only 60 kg/sqm once seismic force is factored in. Covering a roof with 10 cm of natural soil (specific gravity 1.6-1.8) would add 160-180 kg/sqm, exceeding that limit, so it recommends lightweight artificial soils (specific gravity 0.6-1.0) and notes the need for root-barrier sheets to protect waterproofing layers and for automated irrigation.

Only numbers and their conditions are stored, as structured data — never the source's own sentences. Metric and condition names stay in English, as coded.

• 60 kg_per_sqm

  max additional load capacity(existing house roof)

  Design

  region

  Japan

  method

  地震力込みの積載荷重計算、既設一般住居

• 160–180 kg_per_sqm

  added load(natural soil 10cm layer)

  Soil

  region

  Japan

  method

  自然土壌(比重1.6〜1.8)を10cm被覆

• 0.6–1↓ Decrease

  specific gravity wet(artificial lightweight soil)

  SoilControl: 自然土壌の比重1.6〜1.8

  region

  Japan