The Royal Botanic Gardens

This case study describes a typical green roof installation. The Royal Botanic Gardens Edinburgh has extended its 70 acres of spectacular greenery with 1400m² of plants expertly installed at roof level - the crowning glory for a new visitor centre.     

This project was completed using the versatile Diadem green roofing system and Alwitra single ply waterproofing membranes supplied by ICB (International Construction Bureau) Ltd, the UK’s leading supplier of sustainable roofing. Completed in June 2009, it offers a long lasting and eco-friendly cover for the £15.7 million development.

ICB was a perfect choice for the project, owing to its impeccable green credentials. The company offsets its relatively low carbon footprint through the services of co2balance. And in a further demonstration of the commitment to working towards a sustainable environment, it has recently become a research partner and sponsor of the Royal Society for the Protection of Birds, researching the potential that green roofing has in providing suitable feeding grounds and habitats for birds, in particular the sparrow.

Being hardy and requiring little attention, sedum was chosen for planting on the roof. Pre-grown in a medium of crushed brick, expanded clay, pumice and compost, it was easy to lay and meant that the centre could benefit from its good looks immediately. It was installed by ICB licensed contractor Dunedin Roofing of Edinburgh.

The aesthetic of the roof is of particular importance, given that the Visitor Centre, the John Hope Gateway, is designed to integrate into the delicate landscape of the wider gardens. Sharing space with the nearby Queen Mother’s Memorial Garden as well as special plants including the towering Sierra Redwood, the sedum will prove a restrained yet attractive addition to the grounds.

Whilst pleasing to the eye and in keeping with its surroundings, the rooftop will also contribute to the environment. This was especially important to managers of the Royal Botanic Gardens Edinburgh, who intend to use the building as a popular tourist attraction, serving to educate the public on ecological issues.

The Gateway's roof will aid the environment in a variety of ways, stimulating local biodiversity and oxygenating the air. It will also help to combat climate change by providing natural air conditioning - the earth roof cools the building in summer and provides high grade insulation in winter. This also lessens the impact of thermal shock on the structure and other forms of stress on the roof.

As well as controlling temperature, the soil reduces the need for drainage by absorbing rainwater, minimising harmful runoff and limiting the risk of water damage to the building.

The roof is further protected by the high performance Alwitra Evalon V single ply waterproofing membrane, which having passed EN 13948, is root resistant and has a life expectancy of over twenty-five years.

And as Diadem contains as many recycled materials as possible and avoids harmful plasticisers, in tune with the garden’s environmentally friendly philosophy, it makes it the perfect choice for the Gardens.

With over 300 components to choose from, the Diadem system is the most adaptable green roofing system on the market. From plant containers to drainage supplied irrigators, it can be tailored to fit any needs from commercial projects to private homes. Used with Alwitra, it provides a cost effective, environmentally friendly and durable rooftop for any structure.

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