The Boathouse at Avon Tyrrell – An Award Winning Wildflower Roof

Earlier this year we featured this beautiful green roof constructed by Organic Roofs (a specialist Green Roof Installer), designed by  HPW Architects. We are absolutely delighted for Lee and his team at Organic Roofs, who won a prestigious award on Friday at The UK Roofing Awards 2015; an industry-wide event that recognises and rewards outstanding standards of workmanship. Lee is a fine ambassador for the green roof industry and has had a huge amount of experience creating sustainable roofing models using our Wildflower Roof Turf. The award was won for the sustainable roof, green and vegetated category. A closer look at the award winning project is below.
The Brief: Avon Tyrrell is set within the New Forest National Park. A beautiful and historical setting, it now provides the backdrop to a wonderful charity, UK Youth, focussed on providing non-formal learning opportunities. This beautiful site is bound by sensitive planning regulations. HPW, the appointed architectural practice based in the New Forest, have specialised in designing and delivering sustainable buildings for over a decade. The Boathouse was designed with a structure for generating its own income from the solar energy it produces, by feeding surplus electricity back into the grid. It is hoped that within seven years the technology will have paid for itself and in a further eight the cost of the entire building will be recouped. The New Forest National Park Planning Authority provided strict guidelines on sustainable, sensitive credentials that the building must have and in response HPW proposed a wildflower roof to help imbed the building in the landscape and gain support from all parties. Creating a habitat and food source for indigenous wildlife was particularly important as there were a number of threatened species in the area that would benefit from the wildflower species within the roof.
AT-South Elevation 1.0
The Work: The detailing of the green roof for the Boathouse was designed and built using proved and tested principles. Organic Roofs were the specialist green roof contractors who undertook the installation of 200m² of Wildflower Roof Turf (WFT-Roof-41 from Wildflower Turf Ltd). Both HPW and Organic Roofs have worked with the company on a number of different projects and therefore alternative green roof products were not even considered. The setting of the Boathouse meant the roof required instant effect and maturity in order to blend with the landscape along with locally appropriate planting. Having confidence in both the product and the provenance, the pre-established Wildflower Turf meant that there would be an instant greening effect.
Organic Roofs used Hertalan membrane for waterproofing and developed a specific compression fixing to support the substrate and Wildflower Wurf in layers along the length of a 38? pitched roof. This enabled the loadbearing to be reduced and allow for simple finishes to the eaves that would not impact on the ‘green’ feel to the roof. Lee from Organic Roofs allows for at least 100mm of substrate. “The quality of substrate and levels used is incredibly important for the health of the green roof and under specification of substrate will lead to long term problems with the vibrant and sustained growth of wildflowers.”
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The Results: A spectacular project completed with much plaudits from all interested parties. The Wildflower Roof Turf was established in a matter of weeks and a strong display of wildflowers seen in the same growing season. Organic Roofs guarantee their roofs for 20 years and provide a post installation visit and advise on a planned maintenance schedule. The roof will need to be cut with all arisings removed, once a year in the autumn.
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Key Facts: The installation of a wildflower roof can take place at any time of the year and only prevented by snow or frost. The time of year will have an impact on speed of establishment, but being a soil-less product means that roots will embed into the substrate to stabilise the roof very quickly. Other benefits to a wildflower roof include the potential of trebling the lifespan of the roof and helping to moderate stormwater run-off even when saturated, whilst giving a species rich environment of plants native to the UK.