Site analysis

Before designing a green roof, wall or facade it is important to understand the characteristics of the site. The table below outlines what is required in the anlysis of a site for a potential green roof, wall or facade.


Information to collect during a site analysis

Seasonal considerations and climate

Expected maximum and minimum temperatures

Expected rainfall volume and distribution throughout the year

How sun, shade, wind vary on the site throughout the year

How the height of the building might influence some climatic factors

Forecasts on how the local climate might change over time

Local environment

Assess any opportunities or risks that nearby vegetation will have on the site – fire threat, weed or pest invasion, biodiversity migration

Weight loading

Load-bearing capacity

Estimated transient loads, particularly wind forces


Storm water discharge points

Assessment of whether drainage will be sufficient in the case of severe weather


Water collection and storage opportunities, opportunities for delivery of irrigation water and for co-locating stored water with other grey water systems in the building

Existing structure and size

Size of useable roof or wall area

Available space for plants to be grown from ground level upwards

Any slopes or angles to the roof or wall

Quality of existing roof and wall materials


Access to site for cranes and other machinery, and for storage of materials during construction

Access for maintenance and/ or visitors (consider safety such as a parapet on a roof and disability access requirements too)

Access to utilities  – water, electricity

Ensure access for passers-by is not impeded