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French zoo chooses RubberGard EPDM for new okapis enclosure

At the Branféré Animal and Botanical Park, visitors can discover animals in semi-freedom. In the heart of a 45-hectare forest, different species cohabit, including two okapis. This endangered animal, native to the Congo, shares its habitat with antelopes, wattled cranes and dik-diks. Unusual in zoos, the okapis recently joined the Branféré Animal and Botanical Park as part of its endangered species development plan.

Project ID

Le Guerno, France

Project type

New Build

Building type

Recreational building


ca. 550 m²


RubberGard EPDM 1.5 mm


Fully adhered

The new okapi enclosure was designed by the architecture agency Benoît Morin. The building consists of a technical room, lodges for the animals and an observatory for visitors. The agency created a building with an organic architecture that blends harmoniously into the surrounding wooded environment. The structure is made of wood and the shed-type roofs echo the fir trees planted around the clearing. This system allows the interior to benefit from overhead natural light throughout the year, unaffected by falling leaves.

To waterproof the roof of the okapi enclosure, authorized Holcim Building Envelope’ installer CEI 56 convinced the architect to use the RubberGard EPDM roofing membrane. With its outstanding durability and UV resistance, it met the Park’s environmental approach to having all its buildings designed and built in a sustainable way.

Ease of maintenance was also a key requirement. As there are no gutters on the roof, the dead leaves are evacuated at the same time as the rainwater. The RubberGard EPDM membrane is chemically inert, meaning it releases no toxic substances or loss of material. Water can flow freely to the ground, without risk of pollution or harm to the animals.

SVET, Holcim Building Envelope’ local authorized distributor, recommended to the architect and to the installer a membrane thickness of 1.5 mm to guarantee optimal resistance to puncturing caused by falling branches.

Clean and quick installation

The 550 m² of RubberGard EPDM membrane were installed in less than two months, despite the challenges posed by the sloping roofs. The membrane was fully adhered to the wooden structure and was mechanically fixed on the perimeter, making it possible to obtain a completely smooth finish.

“We initially planned to lay the membrane without joints on the two sides of each point and the flatter part. But to avoid the risk of creases during installation, we finally made a joint between these two parts,” explains Maxime Le Quellec, director of roofing company CEI 56. “To obtain a completely black roof that blends into the landscape, we also treated the ridge edges with Holcim Building Envelope’ QuickSeam 18’’ SA Flashing tape. This finishing element perfectly matches the shapes by simple gluing. On the edges of the roof, black lacquered aluminum profiles completed the whole, ensuring the fixing of the membrane to the perimeter, providing protection and an aesthetic finish”, he adds.

The membrane width of 6.10 m also contributed to the quick installation by a team of two to four roofers. “Unlike other sealing systems, EPDM is much less sensitive to weather conditions during installation. We could work on the installation of the steel deck when it rained and then return to the membrane part when the rain stopped. It was a real plus since we were on site between December and January”, continues Mr Le Quellec.

Technical assistance at every step

The complexity of the roof required technical support from Holcim Building Envelope, as well as from SVET. In addition to on-site support, design assistance was provided in conjunction with the architect and the roofing company. SVET provided CEI 56 technical expertise on certain details to guarantee a neat and durable seal over time.