Bio-diversity, photo-voltaics, rainfall alleviation – all in one roof

A forward thinking design has tackled three major construction issues in one installation. Energy production, flood alleviation and providing valuable wildlife habitat have all been encompassed by using three stand-alone roofing features but here they have been integrated to complement each other and enhance the development.

‘The Project Architect – Kris Adelaide of David Miller Architects needed to meet a number of planning issues:

“We had to provide energy production from PV’s, a bio-diverse wildlife habitat and minimise rainfall run off. The challenge was to create viable vegetation with minimal build up depth of the living roof and to keep the overall weight down. Incorporating Aquaten Living roof Plus into the lightweight substrate has enabled us to provide a sustainable Living Roof that will provide essential habitat for years to come. Marrying PV with vegetation was another hurdle, but research and advice from our waterproof team at IPS Roofing and Wallbarn convinced us that this is an effective and valuable combination”

Wallbarn has been involved with Living roofs for many years and has developed a number of products and systems to meet the demands of the industry. Creating a bio-diverse roof to go under and around PV units has unique challenges and coupled with the need to increase rainfall attenuation and reduce overall imposed loading meant an integrated approach was needed.

Wallbarn used a NEW product called Aquaten Living Roof Plus. Aquaten have been developing a range of water attenuation materials over the past two years and they have recently appointed Wallbarn as its UK distributor. Living Roof Plus is a highly absorptive engineered composite that locks in water and helps prevent flooding. Uniquely its high absorption also provides a water reservoir for the plants during the summer, so its use is equally applicable to both wet and arid regions. To keep the imposed weights down a lightweight bio-diverse substrate was blended specifically for this project. This blend uses light aggregates and is more free draining than the standard material and so additional water holding was essential. To go with the open structure of this substrate Wallbarn also developed a special seed mix that provides a wide range of plant species that will thrive under the shade and sun spectrum that the PV creates. Over a period of time the vegetation will develop to the environment it is in, with some species preferring the shade and some full sun. Bare areas also provide additional features for a range of invertebrates and birds.

Our Ecologist Mike Cottage explained:

‘’Combining vegetation and PV is actually a benefit to both. The PV panels provide plants and insects with a variety of light and temperature conditions and the cooling effect of the vegetation and the reduction of airborne dust gives greater performance and less maintenance for the panels – it’s a win-win situation.’’