Green plot ratio
Devised and used successfully by Singapore-based landscape architect Dr Ong Boon Lay, the green plot ratio (GPR) is a relatively recently-developed architectural and planning metric for assessing and facilitating greenery in cities and buildings. Based on a scientific ratio of plant coverage, it can be seen as an indicator of sustainability in urban design.
The GPR recognises that in urban areas, the benefits of plants are not just environmental but can also be recreational, aesthetic and emotional. Their full benefits and their crucial role in the ecology of cities are becoming more valued with the passage of time but the general significance of plants appears to be indubitable. Benefits of photosynthesis, water retention and purification, shade, sound insulation and atmospheric remediation are now seen as critical in the urban environment, in particular given the increase in pollution from vehicle exhausts.
Inspired by the building plot ratio, the GPR is based on a common biological parameter called the ‘leaf area index’ (LAI), which is defined as the single-side leaf area per unit of ground area. According to Dr Lay, the GPR is the average LAI of the greenery on a site and is presented as a ratio that is similar to the building plot ratio (BPR) currently used in urban areas to control maximum allowable developments of built-up floor areas.
The GPR is claimed to allow more precisely regulated site greenery “...without excluding a corresponding portion of the site from building development”. Designers are said to have greater flexibility when it comes to landscape design while simultaneously protecting the green quota in the landscape.
Dr Lay has applied the GPR concept in several design competitions in which he has collaborated with colleagues and architects. In one of these competitions, the GPR was adopted as a planning requirement by the client authority.
The author has stressed that while it is a fundamental metric, GPR is by itself not an indicator for all ecological relationships between plants and cities. A larger set of related metrics need to be developed.
[edit] Related articles on Designing Buildings
- Area.
- Biodiversity in the urban environment.
- Biophilic design research.
- Biophilic design and sustainability.
- Biophilic gym.
- Biophilic design.
- Climate change science.
- Densification
- Ecological impact assessment.
- Environmental impact assessment.
- Green infrastructure.
- Mean lean green.
- Plot.
- Reduce, reuse, recycle.
- Sustainable development.
- Sustainable procurement.
[edit] External references
Featured articles and news
The benefits of engaging with insulation manufacturers
When considering ground floor constructions.
Lighting Industry endorses Blueprint for Electrification
The Lighting Industry Association fully supports the ECA Blueprint as a timely, urgent call to action.
BSRIA Sentinel Clerk of Works Training Case Study
Strengthening expertise to enhance service delivery with integrated cutting-edge industry knowledge.
Impact report from the Supply Chain Sustainability School
Free sustainability skills, training and support delivered to thousands of UK companies to help cut carbon.
The Building Safety Forum at the Installershow 2025
With speakers confirmed for 24 June as part of Building Safety Week.
The UK’s largest air pollution campaign.
Future Homes Standard, now includes solar, but what else?
Will the new standard, due to in the Autumn, go far enough in terms of performance ?
BSRIA Briefing: Cleaner Air, Better tomorrow
A look back at issues relating to inside and outside air quality, discussed during the BSRIA briefing in 2023.
Restoring Abbotsford's hothouse
Bringing the writer Walter Scott's garden to life.
Reflections on the spending review with CIAT.
Retired firefighter cycles world to raise Grenfell funds
Leaving on 14 June 2025 Stephen will raise money for youth and schools through the Grenfell Foundation.
Key points for construction at a glance with industry reactions.
Functionality, visibility and sustainability
The simpler approach to specification.
Architects, architecture, buildings, and inspiration in film
The close ties between makers and the movies, with our long list of suggested viewing.
SELECT three-point plan for action issued to MSPs
Call for Scottish regulation, green skills and recognition of electrotechnical industry as part of a manifesto for Scottish Parliamentary elections.
UCEM becomes the University of the Built Environment
Major milestone in its 106-year history, follows recent merger with London School of Architecture (LSE).
Professional practical experience for Architects in training
The long process to transform the nature of education and professional practical experience in the Architecture profession following recent reports.