BioSolar Green Roofs
A Biosolar green roof is a rooftop that combines vegetation (a green roof) with solar photovoltaic (PV) panels so both systems work together on the same surface. In simple terms, it is a roof that grows plants and generates renewable energy at the same time.
Sika® NatureRoof PV
Sika® NatureRoof PV combines roof mounted solar PV with the benefits of an extensive green roof, creating a BioSolar roof space that both generates renewable energy, enhances biodiversity within the built environment and reduces surface water run-off, whilst the natural evapotranspiration of the green roof provides cooling of the PV panels, increasing solar generated electricity output from the array.
Sika® NatureRoof PV can also be installed above a Sika® RetentionRoof Blue Roof System.
Key System Features
- PV arrays: Both South and East-West facing 10°, 15° or 20°
- Best practice: Follows the GRO Biosolar Best Practice Design Guidance
- Framing system: Adjustable mounting height
Suitable for use with any flat roof, Sika® NatureRoof PV utilises non-roof penetrating BioSolar mounting frames integrated within the green roof system through a modified drainage board. The aluminium support tray is positioned beneath the drainage board, with two aluminium C‑section frame locators extending up through the filter fleece and growing medium. These locators provide the mounting points for the aluminium solar frames before the solar frame rails are installed.
Both South and East-West facing PV arrays at 10°, 15° or 20° can be used and the Sika® NatureRoof PV system is ballasted down using the weight of the green roof growing medium. The design loads for each individual roof are calculated based on the site location, elevation, topography, wind and snow loads to BS EN 1991-1 Eurocode 1. Actions on structures. General actions. Wind actions.
Sika® NatureRoof PV system designs follow the GRO Biosolar Best Practice Design Guidance considering best practice designs for fire safety, including distance from the external face of the building, abutting external walls, rooflights, SVP’s, lift over-runs etc. Fire breaks will also be allowed between arrays as will maintenance access. One specific benefit of the Sika® NatureRoof PV framing system is its ability to adjust the mounting height of the lower front edge of the PV panel, from 200mm upwards, enabling adaption to comply with any specific design requirements, such as those from the Department for Education (DfE) Construction Framework 2021.
Typically used in new build construction, Sika® NatureRoof PV is also suitable for retrofit/refurbishment applications with all systems specified with BBA Certification. Sika roof systems have a life expectancy of ‘at least 35 years’ or better.
When installed by a Sika® Verified or Certified Roofing Contractor with Sika® NatureRoof and Sika® SolarRoof Contractors, the project will be eligible for a comprehensive Sika® System Guarantee.
For support in designing a Ballasted Blue Roof please contact your local Sika® Area Technical Manager.
