If you are an architect or contractor looking to incorporate a low-maintenance but still visually and environmentally rich green roof into your next project, a sedum roof may be the perfect answer.
Sedum roofs are a great way to add greenery to buildings while also providing numerous benefits such as reducing stormwater runoff, improving air quality, and reducing energy consumption. However, creating a low-maintenance sedum roof that is able to provide these qualities, requires careful planning and consideration.
To help you create the perfect low-maintenance sedum roof for your next project, we have compiled some helpful tips and tricks all recommended by our industry-leading green roof experts here at Viritopia.
Choose the Right Sedum Species
Selecting the right type of sedum is crucial for creating a low-maintenance roof. Some species are more tolerant of drought and poor soil, while others require more maintenance.
Additionally, the location of the building the roof will be on needs to be considered, this includes climate, exposure to sun and wind, and other site-specific factors.
There are several sedum species that are well-suited to the UK climate and can thrive on a sedum roof. Here are some of the most commonly used sedum species in the UK:
- Sedum acre (Gold Moss Stonecrop): This is a low-growing, mat-forming species with yellow-green foliage that turns bronze in the autumn. It is drought-tolerant and can handle full sun exposure.
- Sedum album (White Stonecrop): This species has small, white flowers and blue-green leaves that turn red in the winter. It is tolerant of cold and damp conditions.
- Sedum hispanicum (Spanish Stonecrop): This species has blue-green foliage and pink flowers that bloom in the summer. It is a hardy species that can handle both wet and dry conditions
- Sedum spurium (Two-row Stonecrop): This species has red or pink flowers that bloom in the summer and glossy, green leaves that turn burgundy in the fall. It is a tough species that can handle a range of conditions.
- Sedum kamtschaticum (Orange Stonecrop): This species has bright yellow flowers and small, fleshy leaves that turn red in the autumn. It is a hardy species that can handle cold and wet conditions.
Although these are the recommended species for sedum roofs in a UK climate, It is always best to consult with a green roof specialist or horticulturist to determine the best species for your specific location and site conditions.
Use a High-Quality Growing Medium
The growing medium is a crucial component of a sedum roof system, as it provides the necessary nutrients and support for the sedum plants to thrive. A high-quality growing medium should be lightweight, well-draining, and able to retain moisture to ensure that the sedum plants are healthy and require minimal maintenance.
A lightweight growing medium is important for several reasons. Firstly, it helps to reduce the weight of the sedum roof, which can be a critical factor in some buildings' structural integrity. Secondly, it allows for easier installation and handling of the growing medium, which can be particularly important for larger commercial buildings. Finally, a lightweight growing medium will also help to reduce the load on the building's drainage system, which can help prevent issues such as waterlogging and flooding.
The growing medium must also be well-draining, as sedum plants are susceptible to root rot and other water-related issues. A well-draining growing medium will ensure that excess water can quickly drain away from the sedum roots, preventing them from becoming waterlogged and potentially dying.
Additionally, the growing medium should be able to retain moisture, as sedum plants require a consistent supply of water to thrive. A growing medium that can hold onto moisture will help to ensure that the sedum plants have access to the necessary water, even during periods of drought or hot weather.
Which substrate is best for s sedum roof?
As green roof specialists, we firmly believe that natural is always better! Using a natural substrate means you will have greater flexibility in plant selection, allowing native species to thrive, pollinator planting, and sources of nectar. This creates a habitat for bees and burrowing insects and encourages natural colonisation. Substrates for a successful sedum roof should have less than 10% of organic substrate. The increase of volcanic material ensures a free-draining composition.
Prioritise Water Management
Water management is a critical aspect of designing a low-maintenance sedum roof and should be prioritised in the early stages of your design.
Sedum plants are notorious for getting root rot from being exposed to damp conditions, so poor water management could be disastrous for the success of your sedum roof. Excess water can lead to an increase in maintenance requirements and potentially cause the plants to become damaged or die which can be costly to replace and repair.
Proper water management can help to prevent these issues from occurring. This can include features such as drainage layers, which allow excess water to drain away from the sedum roots, preventing them from becoming waterlogged. Additionally, an irrigation system can be installed to ensure that the sedum plants receive the appropriate amount of water to thrive, without the risk of excess water accumulating on the roof.
Another important aspect of water management on a sedum roof is managing stormwater runoff. Sedum roofs are excellent at absorbing and filtering rainwater, but without proper management, excess water can flow off the roof and potentially cause damage to the building's exterior or surrounding landscape. To prevent this, features such as gutters and downspouts can be installed to direct excess water away from the building's foundation and into appropriate drainage systems. Rainwater can also be harvested for dryer months, furthering the sustainability of the roof.
Consult a Sedum Roof Specialist: Viritopia
As you can tell, we’re huge fans of green roof systems at Viritopia. In fact, we’ve installed over 100 million plants since we began experimenting with green roof systems in 2005.
If you would like to discuss the benefits of a sedum roof further or would like to discuss your project requirements with an expert, contact us at Viritopia today.