Specifying Green Roofs on External Bike Stores to Support Biodiversity and Active Travel

The UK’s average cycling mileage per year has been gradually increasing since 1993, rising to 4.2bn miles in 2021. Combined with a reduction in annual mileage by UK motorists, this demonstrates that individuals are increasingly choosing a sustainable and cost-effective means of transport, fostered through a conscious effort to promote sustainability through urban planning.

While the UK seeks to encourage cycling uptake, the provision of reliable, secure bike storage remains a crucial linchpin. As urban landscapes evolve, and in a pursuit of a greener future, specifying green roofs on external bike stores provides significant value for developments, helping to support a demand for secure bike storage, promoting greening principles in urban spaces, and enabling increased biodiversity.

Active Travel on the Rise

While leisure continues to be the main driver for active travel in the UK, Data analysed by Cycling UK for 2022 revealed that significantly more people have turned to utility cycling as a convenient mode of sustainable transport, largely in response to rising fuel prices and disruptions to public transport, with levels rising by 47% on weekdays and by 27% on weekends.

This rise has also been encouraged by a greater emphasis on implementing sustainability strategies and methodical urban planning, with the significant example of this being Active Travel England. The £32.9m Government scheme was introduced in January 2023, forming an aspect of the UK Government’s 10-Point Plan for a Green Industrial Revolution.

While cities and towns seek to establish better bike lanes to make cycling safer and more accessible, the provision of secure bike parking facilities has often been overlooked or integrated as something of an afterthought. A recent research report found that up to 1.5m cyclists are deterred from commuting via bike due to the lack of secure storage facilities at their workplaces.

A Greener Future

Most new developments in the UK do require provisions for bike parking, with planning decision notices containing conditions for both the type and number of bike parking spaces required to pass. Setting the standard for best practices in sustainable development is BREEAM, which aims to reduce the negative impacts of construction and development on the environment. Transportation is a key factor in BREEAM accreditation, and assessments actively take notice of how alternative forms of transportation that promote sustainable and eco-friendly practice are implemented. BREEAM compliant bike storage is assessed in context with reference to its location and the intended user profile.

All new developments within England are also now obligated to deliver measurable Biodiversity Net Gain (BNG), which was implemented primarily to protect natural habitats from land developments and sustain biodiversity outputs in the UK for the long-term. All new planning applications are required to demonstrate how their operation will leave the biodiversity of a site in a measurably improved state than in pre-development, with these changes set to be enforced in January 2024.

Moreover, Plan Policy G5 is a recently implemented scheme from the Greater London Authority, requiring all major new developments in the capital to improve the provision of green infrastructure by integrating urban greening as a fundamental aspect of site and building design. Enabling benefits such as enhanced biodiversity and reduction of the urban heat island effect, urban greening can be used to help meet other policy requirements, and it’s advised that developments consider urban greening alongside BNG as part of their project design brief.

Specifying a Green Roof on External Bike Stores

Acting as a valuable resource for achieving BNG targets, and helping to contribute towards urban greening (categorised as surface-cover types), green roofs are a relatively new concept for built-up urban spaces, combatting urbanisation challenges and reducing the urban heat island effect by reducing reflections from solid roof coverings and establishing greening plants that have a cooling effect.

Specifying a green roof an external bike store enables a new development to:

• Promote sustainability and active travel principles 
• Encourage cycling uptake by establishing safe and secure bike storage facilities
• Support the development of essential greening elements in built-up urban spaces
• Foster enhanced levels of biodiversity and the creation of new habitats

External bike stores are ideally suited to green roof applications, provide a consistency of design, reducing the visual impact of the structure, and enabling the softening effect of nature on urban landscapes. Considering a number of technical design elements is necessary to ensure optimum output and meet criteria guidelines, as per The GRO Green Roof Code. These include:

• Structural Design – Green roofs must comply with all relevant structural design criteria. The loading guide for green roofs advises 65 kg/m2 for a lightweight extensive sedum roof; 175 kg/m2 for a biodiverse wildflower roof, and 250-400 kg/m2 for an intensive roof.
• Waterproofing – The primary waterproofing layer is critical to the performance of a green roof system. Its suitability must be assured by the BBA Certification process and needs to offer permanent protection by a membrane which prevents plant roots from growing through it. 
• Substrate- Specifically designed to hold the optimum level of moisture, nutrients and air required for sustainable plant development, the growing medium typically contains a mix of organic and porous inorganic material.
• Vegetation Type – A sedum mat is reliable and is able to be established quickly, while a wildflower mat offers a wider selection of species. Seed sowing tends to be a long and slow process but can enable a bespoke mix to be integrated, while pre-cultivated plugs are a reliable bespoke method that are planted directly into the substrate growing medium.
• Fire Resistance – Green roofs should be designed to provide the necessary resistance to the external spread of fire. The substrate depth should be a minimum of 80mm, with a maximum 20% organic content. Fire breaks typically consist of non-vegetated strips and should be provided with a diameter of 30mm, or 50mm if using green roof pebbles.
• Access and Maintenance – All green roofs require some degree of maintenance. Providing edge protection and a means of safe access by a roof anchorage system or containment system is strongly recommended, alongside a fall protection system to ensure safety for maintenance workers.

Urbanspec Green Roof Bike Stores

Aided by a lower structural height that helps to reduce ongoing maintenance costs, the roofing system of urbanspec external bike stores can be easily adapted to support the integration of a green roof system, making the introduction of valuable biodiversity into the built environment as uncomplicated as possible.

This enables green roof bike stores to be accommodated from the outset of the design process, incorporated into planning applications for BNG targets and to achieve BREEAM performance requirements, while providing opportunities to link with corresponding green elements on a development.

Green roofs on urbanspec bike stores can be specified as either extensive or intensive, with extensive systems supporting primarily sedum plants, while an intensive system provides an increased substrate depth, supporting a mix of sedum and wildflower plants.

A substantial resource and knowledge base enables urbanspec to simplify the specification process, utilising CAD models, NBS specifications and datasheets available for download. Supporting CPD programmes provide clarity on the optimal approach to aspects such as security considerations and effective space planning.