Policy information sourced from the Islington Local Plan
G5 Green roofs and vertical greening
- Developments proposals must use all available roof space to incorporate biodiversity-based extensive green roofs, subject to other planning considerations. Developments involving the extension of existing buildings must seek to retrofit extensive green roofs on existing roof areas where feasible, in addition to providing green roofs on the extension.
- Green roofs must be considered at the earliest possible stage of designing a proposal to ensure their effective operation. They must be designed to:
- maximise benefits for biodiversity, sustainable drainage and cooling;
- promote ecological diversity including planting based on wildflowers and a maximum of 25% sedum planting;
- have a varied substrate depth of average 80-150mm, unless it can be demonstrated that this is not reasonably possible; and
- be easily monitored, allowing for an ongoing effective process to inspect and monitor the quality of the green roof.
- Major development proposals must accommodate surface water storage, where sustainable drainage requirements are applicable in accordance with Policy S9, by incorporating blue roof stormwater attenuation, unless it can be demonstrated that this is not possible.
- Developments proposing the installation of roof level solar panels are required to incorporate the panels over a green roof area to form a ‘bio-solar roof’, where the overarching biodiversity and drainage functions of the green roof will not be adversely affected.
- Biodiversity-based extensive green roofs are the Council’s clear priority in terms of green roof provision. The installation of intensive or semi-intensive green roofs to provide amenity space will only be acceptable where it is clearly demonstrated that this is required to meet other policy requirements, and where the primary biodiversity, sustainable drainage and cooling functions of the green roof will not be adversely affected. Dedicated areas of biodiversity-based planting must be maximised on intensive or semi-intensive green roofs and amenity space must not cover the majority of roof space.
- Major developments are encouraged to consider tree planting and food growing opportunities as part of intensive and semi-intensive green roofs where feasible, and where the additional weight requirements can be supported.
- New-build developments, and all major applications (including those involving refurbishments) must maximise the greening of vertical surfaces as far as reasonably possible. Vertical greening must be designed to:
- maximise benefits for biodiversity, sustainable drainage and cooling;
- avoid excessive water demand and employ a watering system that does not rely on mains water supply or a pumped irrigation supply;
- promote ecological diversity through planting a range of appropriate species and incorporating micro habitats to support Islington’s Biodiversity Action Plan, including nesting boxes for birds or bats where possible;
- provide growing conditions suitable for the selected plant species, and require minimal maintenance; and
- incorporate planting rooted in soil from both ground level and roof level planters where practical.
- The design and management of green walls must include consideration of building structure and character, including architectural and historic features, in order to ensure such features are preserved and damage is avoided. A management plan may be required and conditioned to guarantee that any measures are carried out.
For more information please see the Islington Local Plan