Getting it right through design

There are fundamental principals that apply to the design of a green roof, regardless of the proposed landscaping, location or climate. The specified solution must replicate nature within the build up and be able to support the vegetation.

The first step - What is the landscaping finish to look like?

The primary decision is the type of landscape required that best suits the rationale behind the development, whether it is an intensive, simple intensive, extensive or biodiversity roof. Whatever the landscape chosen, the plants will have some basic requirements to sustain them; nutrients, a balance between moisture and drainage to suit the vegetation, and aeration to the root systems.

The next step - Planning the green roof to meet the needs of the vegetation

Once the vegetation finish has been determined the structural and design considerations and green roof components can be proposed.

Designing to protect the building's construction and flat roof waterproofing is vital when delivering a green roof as many additional forces can affect the structure.  Green roofs are installed on roof pitches ranging from 1° to around 30°. Fundamentally it’s about finding the balance between requirements for water storage, drainage and irrigation; sufficient depth of growing medium to support the intended vegetation and weight loading levels; as well as meeting the regulatory needs for construction, firesafe access and the duty for maintenance.

  • Codes of Practice

    To date there are no British Standards to guide Specifiers, Contractors, and their clients as to the best method to achieve this. At present the most widely accepted standard amongst the leading green roof suppliers in the UK, is the German FLL standards.

    The Green Roof Organisation (GRO) is a partnership of Industry and Stakeholders coming together to develop guidance for specification, design, manufacturing, installation and maintenance of Green Roofs.  You can download the GRO Code of Practice 2014 here ►

  • Design challenge?

    If you need help and advice on how to design a green roof your local technical manager will be able to support you throughout the whole process.

    Call Dan Taylor on 01473 267145, to arrange a conversation either by phone or at your office with your technical advisor.

Download our useful Green Roof Design Considerations guide.