top of page

 Frequently Asked Questions

Why is it important to maintain a green roof in the UK and how do you maintain a green roof?


Maintaining a green roof in the UK is essential for several reasons, and proper upkeep ensures the longevity and effectiveness of this sustainable feature.

What is the Importance of Green Roof Maintenance in the UK?

  • Sustainability: Green roofs contribute to environmental sustainability by promoting biodiversity, reducing urban heat island effects, and improving air quality. Regular maintenance helps sustain these ecological benefits over time.

  • Stormwater Management: Green roofs aid in stormwater management by absorbing and slowing down rainwater runoff. Regular maintenance ensures that drainage systems remain functional, preventing issues like waterlogging and potential damage to the roof structure.

  • Insulation and Energy Efficiency: Well-maintained green roofs continue to provide insulation benefits, reducing energy consumption for heating and cooling. This contributes to overall energy efficiency in buildings.

  • Aesthetic Appeal: Green roofs enhance the visual aesthetics of buildings and the surrounding environment. Proper maintenance ensures that the vegetation remains vibrant and attractive, contributing positively to the urban landscape.

  • Longevity of Roof Structure: Regular inspections and maintenance help identify and address issues promptly, preventing damage to the roof structure. This proactive approach extends the overall lifespan of the roof.


How Do I Maintain a Green Roof in the UK?


  • Regular Inspections: Conducting regular inspections helps to identify any signs of damage, plant health issues, or drainage problems. Early detection allows for timely intervention.

  • Weed Control: Managing weed growth prevents weeds from competing with desired vegetation. Remove invasive species and ensure that the chosen plants are thriving.

  • Irrigation Management: Monitor and adjust irrigation systems as needed, particularly during dry periods. Adequate water supply is crucial for plant health.

  • Drainage Maintenance: Keep drainage channels and outlets clear of debris to prevent waterlogging. Ensure that the drainage system is functioning properly to manage excess water.

  • Fertilization: Provide necessary nutrients to the plants through periodic fertilization. This helps maintain the health and vitality of the vegetation.

  • Roof Structure Inspection: Check the structural integrity of the roof regularly. Address any issues with the waterproofing membrane or other structural components promptly.

  • Community Engagement: Involve the local community in the maintenance process, fostering a sense of ownership and responsibility for the green roof. This can also encourage community participation in related environmental initiatives.

  • Seasonal Adjustments: Consider seasonal variations when planning maintenance activities. Adjust care routines based on factors such as temperature, sunlight, and precipitation.

By implementing a comprehensive maintenance plan that addresses these aspects, green roofs in the UK can continue to fulfill their ecological, aesthetic, and functional roles effectively over the long term.


Why are sedums used on green roofs?

Sedum plants are commonly used on green roofs for several reasons, and their characteristics make them well-suited for this specific application. Here are some key reasons why sedum plants are preferred for green roofs:

  • Drought Tolerance: Sedums are succulent plants known for their ability to store water in their leaves, stems, and roots. This makes them highly drought-tolerant, which is advantageous in green roof applications where water availability can vary.

  • Low Maintenance: Sedums are generally low-maintenance plants. Their hardiness and adaptability mean they require minimal care, making them suitable for green roofs, where accessibility for maintenance may be limited.

  • Shallow Root System: Sedums typically have shallow root systems, which is beneficial for green roofs with limited substrate depth. Their ability to thrive in shallower growing mediums makes them ideal for extensive green roof systems.

  • Weight Considerations: Sedums are lightweight plants, and their shallow root systems contribute to the overall lightness of the green roof. This is crucial for ensuring that the structure can support the added weight without exceeding load-bearing limits.

  • Seasonal Interest: Sedums often exhibit vibrant colors, particularly in the fall when they may turn shades of red, orange, or purple. This seasonal interest adds aesthetic appeal to green roofs, enhancing their visual impact.

  • Biodiversity Support: While sedum roofs are often associated with extensive green roofs, they still contribute to biodiversity by providing habitat and food sources for various insects. This can attract pollinators and other beneficial wildlife to the rooftop environment.

  • Resistance to Pests and Diseases: Sedums are known for their resilience against common pests and diseases. This resistance reduces the likelihood of issues that might require chemical interventions, aligning with the eco-friendly and sustainable goals of green roofs.

  • Adaptability to Harsh Conditions: Sedum species can tolerate a range of environmental conditions, including exposure to wind, sunlight, and temperature extremes. This adaptability makes them well-suited for the challenging conditions often present on rooftops.

  • Erosion Control: The dense mat-forming growth habit of many sedum species helps prevent soil erosion on green roofs. This is particularly important for maintaining the integrity of the growing medium and overall roof structure.

  • Quick Establishment: Sedums are known for their rapid establishment and growth. This characteristic is beneficial for green roofs, allowing for quicker coverage and establishment of the living roof system.

In summary, sedum plants are used on green roofs due to their resilience, adaptability, low maintenance requirements, and suitability for the specific environmental conditions and weight limitations associated with rooftop installations. Their use contributes to the success of extensive green roof systems, promoting sustainability and ecological benefits.

What is Biodiversity Net Gain (BNG)?

Biodiversity Net Gain (BNG) is a concept that aims to ensure development projects deliver a quantifiable increase in biodiversity. In the UK, BNG is set to become a mandatory requirement for certain types of development, with the goal of enhancing natural habitats and promoting biodiversity. Green roofs can play a crucial role in achieving biodiversity net gain.

What are the key principles of Biodiversity Net Gain?

  • Quantifiable Improvement: BNG requires developers to demonstrate a measurable increase in biodiversity compared to the baseline condition before development.

  • Metric-Based Approach: The increase in biodiversity is often measured using specific metrics, such as the Defra Biodiversity Metric, which quantifies the value of different habitats and species.

  • On-Site Enhancement: Developers are encouraged to prioritize on-site enhancements, ensuring that biodiversity gains directly result from the development project.

  • Habitat Creation and Improvement: BNG emphasizes the creation and enhancement of habitats, including green spaces and wildlife corridors, to support a variety of species.

  • Long-Term Management: Long-term management plans are crucial to sustain and enhance biodiversity gains over time.

How do Green roofs contribute towards BNG (Biodiversity Net Gain)?


Green roofs can significantly contribute to Biodiversity Net Gain (BNG), which refers to the idea of enhancing and improving biodiversity in a specific area, offsetting any losses that may occur due to development or other human activities. Here's how green roofs contribute to Biodiversity Net Gain:

  • Habitat Creation: Green roofs create additional habitats in urban environments, providing a space for a variety of plants, insects, birds, and other wildlife. The vegetation on green roofs can serve as homes for insects, birds, and even small mammals.

  • Plant Diversity: Green roofs often host a diverse range of plant species, especially when designers incorporate a mix of native or adapted plants. This diversity attracts different pollinators, contributing to overall biodiversity.

  • Insect and Invertebrate Support: The plants on green roofs attract various insects, including pollinators such as bees and butterflies. Additionally, the substrate and vegetation provide shelter and breeding opportunities for invertebrates, contributing to a thriving insect community.

  • Bird Habitat: Green roofs, particularly those with a variety of plant types, can attract birds. These spaces offer nesting sites, foraging opportunities, and refuge for birds in urban areas where natural habitats may be limited.

  • Bee-Friendly Environments: Many green roof plants are attractive to bees and other pollinators. By providing a bee-friendly environment, green roofs support pollination, which is crucial for the reproduction of flowering plants.

  • Biodiversity Connectivity: Green roofs can act as stepping stones or green corridors, connecting fragmented green spaces in urban areas. This connectivity is vital for the movement of wildlife, promoting genetic diversity and resilience in populations.

  • Microbial Diversity: The substrate on green roofs supports microbial life, contributing to soil health and enhancing overall ecosystem functioning. Healthy soil ecosystems are essential for the success of plant life and the organisms that depend on them.

  • Education and Awareness: Green roofs also contribute to Biodiversity Net Gain by raising awareness and educating communities about the importance of biodiversity. They serve as tangible examples of how urban spaces can support diverse ecosystems.

  • Stormwater Management: Green roofs can help manage stormwater runoff, preventing soil erosion and supporting aquatic biodiversity in local water bodies. Reduced runoff also minimizes the transport of pollutants into water systems.

  • Climate Resilience: Biodiverse green roofs contribute to climate resilience by creating ecosystems that are better able to adapt to changing environmental conditions. A diverse range of plant species can enhance the ability of green roofs to withstand stressors like extreme weather events.

In summary, green roofs play a multifaceted role in promoting biodiversity, supporting various species, and creating resilient ecosystems in urban environments. By incorporating these features, green roofs can make positive contributions to Biodiversity Net Gain, helping offset biodiversity losses associated with human activities and urban development.

bottom of page