A functional rooftop inspired by the rolling hills of the English countryside

The Batsford Arboretum and Garden Centre on the edge of the Cotswolds nature reserve is home to the largest private collection of trees and plants in England. The collections at Batsford cover a wide range of plants from around the world, with an emphasis on the Far East. With an illustrious past dating back to the late 19th century, the Arboretum commissioned a £2M redevelopment project in 2011 with a strong focus on sustainability. A new visitors’ centre was part of that plan, housing a garden shop and a terrace café, with an impressive wavy roof as a true eye-catcher.

BUILDING ID
Location

Moreton-in-Marsh, United Kingdom

Project completion

2011

Designed by

John Falconer Associates

Project type

new build

Building type

commercial

Roof surface

ca. 1,100 m²

Roofing membrane

Firestone RubberGard EPDM 1.1 mm

How did this unique design come about? 

Architectural practice John Falconer Associates envisioned a structure that would make the new Batsford Arboretum visitors’ centre blend seamlessly and organically with the surrounding landscape, using as many natural and renewable materials as possible. The result is a great example of sustainable architecture. The building is made from sustainably grown and FSC-sourced timber. A ground source heat pump provides underfloor heating in winter and, most interestingly, natural sheep’s wool from a rare British breed has been used to insulate the whole building.

For the roof, John Falconer Associates presented a unique and challenging ‘wave’ design made in plywood, emulating the rolling Cotswold hills. The roof also had a low profile to minimize its visual impact on the landscape and reduce energy consumption.

This plan came with challenges and requirements in terms of selecting the optimal roofing system: it had to be lightweight and flexible enough to perfectly follow the curves of the plywood roof deck and form clean edge details, ensuring a perfect waterproofing function. The idea was also to allow rainwater harvesting, which was a logical solution for such a rainy region. Last but not least, the roofing system had to be in line with the project’s overall environmentally friendly and energy-efficient approach. 

WHY EPDM?

After careful consideration, the architects specified the use of an EPDM roofing system. EPDM membranes are 100% cured, single-ply roofing membranes made of a synthetic rubber Ethylene-Propylene-Diene Terpolymer. Thanks to their stable chemical composition, they offer high resistance to UV radiation, ozone, alkaline rains and extreme temperature fluctuations. Robust yet flexible, EPDM roofing membranes adapt to the structural movement of buildings during their entire lifetime. With a life expectancy of more than 50 years, they are also the most sustainable roofing membrane in the market, as stated – among others – by the Dutch Institute for Building Biology and Ecology (NIBE).

In addition to its longevity and outstanding waterproofing qualities, EPDM is a chemically inert material which does not contain any plasticizers or flame retardants and therefore does not release toxic substances into the environment. This makes EPDM roofing membranes particularly well suited for the collection and use of run-off rainwater, as is the case at the Batsford Arboretum’s visitors’ centre.

The EPDM roofing membrane used in this project was Firestone’s RubberGard EPDM, with a thickness of 1.1 mm. The membrane was fully adhered to the irregular, wavy shape of the plywood roof deck using contact adhesive. To harvest the rainwater, the roof outlets were set into large sumps in the low points of the curves. Water is then collected in irrigation tanks below the main building and used to water the plants in the garden centre.

How is the system functioning after almost a decade in use? “Nine years on, the EPDM roofing system is still performing very well and we are pleased with it”, says Stuart Priest, Director of Operations at the Batsford Arboretum. “Other than sweeping down the gullies and cleaning out the drain points a couple of times a year there has been no need for bigger maintenance works.”

THE ROOF ASSEMBLY
01

RubberGard EPDM roofing membrane

02

Plywood roof deck

There is a lot to
discover about EPDM

EPDM is the most future-proof roofing solution when it comes to sustainabilityperformance and design freedom. Learn more about the role it played within this project and many others by discovering its benefits.

How did EPDM elevate this project?

Non-Toxic

EPDM is inert and doesn’t release any toxic substances during or after installation. Fully safe for people and the environment, it allows to collect rainwater for domestic use without risk.

UNUSUAL FORMS

Freedom of design is key to those creating big things. Thanks to its flexibility and availability in big, single-ply sheets, EPDM supports creative solutions. It also enables future transformations and placing new objects on the roof.

Designing beyond limitations

Our buildings become symbolic of the times we live in, reflecting the spirit of a given era, attending to different needs, lifestyles, functions… “Architecture should speak of its time and place, but yearn for timelessness”, says one of the most prominent architects of our time, Frank Gehry. Exploration of the emerging technological possibilities and imagining how a new value can be created in people’s lives, have been the guiding principles of the architectural pioneers compelled to respond to the challenges of their time. Today’s key challenge - sustainability - is adding new dimensions to the debate, bringing together form, function, the responsible choice of materials and long-term thinking. Keeping up has never been more important.