Constructed in 1995 but opened in 1996, the Horniman Museum is located in Forest Hill, southeast London. The CUE Building (formerly the Centre for Understanding and the Environment) has a rich wildflower meadow greenroof. Donated in 1901 to the people of London by Victorian tea trader Frederick John Horniman, the museum and gardens encompasses seven hectares of award-winning landscaped gardens and has an internationally renowned anthropological collection. “But the Horniman?s collections are not restricted to its interior spaces. In the case of the energy-saving CUE Building, it is the building itself that has become a favourite exhibit. Designed to act as a conceptual and symbolic link between the Horniman?s collection of artefacts and the natural world of the gardens, the building was commissioned to be a place in which to teach and encourage a greater awareness of environmental issues,” states an article in the June 2005 issue of Green Spaces by Sarah Bennett. The client wished to promote sustainability on many levels, including as a platform to support a wide variety of wildlife and also contribute to the energy efficiency of the building.
The unusual roof design contains two slopes: one facing south at 8 degrees and the other, a north-facing, 27 degree slope.Greenroof Details:The Green Spaces article states “The roof consists of a ply box or ?cassette? containing insulation, with a ventilated void above it. A waterproof membrane was used on top of the plywood deck. This would ordinarily have a lifespan of more than 50 years on an exposed roof, but under a living roof it is protected from heat and UV damage by the vegetation, thus prolonging its life. A felt layer was placed on top of the waterproof membrane to reduce the likelihood of anything sharp penetrating it. A wooden batten grid was then placed on top of the felt layer in order to stabilise the sub-soil ? especially on the steep slopes. Over time the batten woods rot, but by then the plants have rooted and matted together, holding the soil in place. Low nutrient soil to a depth of 100mm was used in order to benefit the greatest variety of wild flowers ? high nutrient soil encourages robust types, which crowd out smaller, more delicate species. A layer of coir matting was then placed onto the soil before the grass turf was laid. Wildflower plugs were planted into the turf and a regular mix of wildflower seeds was scattered generously on top.”A sprinkler placed atop the roof waters the meadow effectively during extreme periods of drought, although plans include installing a permanent irrigation system. Maintenance also includes mowing in the autumn after the plants have flowered and seeded; the hay is removed and then composted in museum gardens. Plant biodiversity is huge as plants have fluctuated over time due to climate changes, roof microclimates, and bird and wind plantings. Seasonal plants include white ox-eye daisies, cowslips, meter-high meadow grasses, pansy, wild clary kidney vetch, musk mallow, wild carrot and mosses. Fauna biodiversity is also great, and British entomologist Richard Jones found more than 50 species of insects from the smallest species of ant to Britain?s largest hoverfly.