We are so proud that Sky Garden are finalists in the 2019 UK Roofing Awards for our work done at Pinewood Studios together with Sir Robert McAlpine! Fingerscrossed Sky Garden brings it home! The winners will be announced at a glittering awards ceremony tonight (10th May 2019) at the InterContinental London - The O2. Good Luck to all the finalists.
Located near Iver Heath in South Buckinghamshire, Pinewood Studios is the world-famous provider of studios and services to the global film and television industries. Synonymous with world class British and international productions, Pinewood has an impressive heritage and has been home to some of the most successful features films and TV shows ever made.
Due to Pinewood’s business growth, a significant expansion of facilities was sought on adjacent Green Belt land, including 5 film stages as part of the phase 1 construction. Planning Permission was granted, subject to not only mitigating the Ecological impact on the existing land, but an ambitious strategy of site-wide Ecological enhancement, including Green Roofs on the new stages, the smallest measuring well over 2,000m².
Sky Garden assisted the project team during the year-long design phase, including the client Pinewood, project Consultants Arup and main contractor Sir Robert McAlpine, along with other specialist trades and stakeholders. Sky Garden were delighted to play a vital role in the Green Roof design and ultimately see the project through to its successful completion in 2017.
Necessity of the Green Roofs.
The footprint of the newly developed land contained arable meadows of grassland and flowering plants, home to a diverse range of wildlife including breeding Skylarks (Alauda arvensis). This popular farmland bird, well known for it’s quintessential Spring and Summer song that is sung high in flight, has declined dramatically and is now a protected Red List species: “In the UK, the population halved during the 1990s, and is still declining. In the preferred habitat of farmland, skylarks declined by 75% between 1972 and 1996” (source RSPB).
As part of the Phase 1 Ecological strategy, a key Planning Condition was to create Green Roofs on the 5 new film stages. These Green Roofs would not only recreate the meadows lost to the footprint of the new development, but aim to recreate suitable habitats for Skylarks to nest, feed and raise their young.
Sky Garden worked with the Ecologists at Arup to develop the Skylark-specific habitats. Studies by Environmental Groups such as the RSPB had shown that Skylarks need a range of favourable conditions to be able to breed successfully. These include a lack of disturbance, good nesting cover, varied vegetation structure and a diverse range of insects and seeds to feed on.
A range of 4 habitats were designed for each roof, arranged in natural-looking zones;
- Tussock Grassland with 8 grasses and 16 wildflower species – to give thick grassy cover to conceal nests and chicks from predators and bad weather. Chosen species included quaking grass, sheep’s fescue, yarrow, meadow cranesbill and lady’s bedstraw.
- Wildflower Meadow with 6 grasses and 25 wildflower species – to provide rich foraging and elevated plant height with good cover for fledgling birds and perches for adults. Structural species included vipers bugloss, dark mullein and greater knapweed.
- Short Perennial Wildflowers, with 6 sedum stonecrops and 28 wildflower species – as a more sparsely vegetated area which Skylarks prefer for approaching their nests on the ground and prolific insect life for food. Lower-growing species included wild thyme, meadow saxifrage and maiden pink.
- Bare ground, an area of non-vegetated bare limestone aggregate that would encourage a high diversity of spiders, beetles and other invertebrates, which need exposed areas for basking and hunting, and additional forage for the Skylarks.
- Cornfield Annuals were also added to the mix, 7 species, including some of our declining native farmland flowers such as corn marigold and corn-cockle.
The green roofs were also an opportunity to benefit many other species of wildlife and invertebrates, especially pollinating insects such as solitary bees, butterflies, hoverflies, predatory wasps and beetles. The wildflower species were chosen with this in mind and even in the first Summer after germination, the roofs were humming with insect life. This in turn provides food for birds such as swallows and house martins, and several species of bats which are resident on or near the site.
Sky Garden designed the three seed mixes, using only native annual and perennial plant species with 100% native provenance. The precious sacks of seed were hand-delivered to site and mixed with a suitable carrier material, then sown by hand over the roofs to the 3 habitat zones in March 2017.
Sky Garden’s involvement has continued since installation handover, as we are responsible for the maintenance of the green roofs. Such is the sensitivity of the Skylark’s breeding habits, we carry out our maintenance outside of the nesting season, from mid Autumn to end of January. The vegetation is maintained to a carefully planned rotational programme, so that areas of the vegetation zones are cut back of left intact, then reversed the following year. This allows invertebrates to over-Winter in the vegetation and gives the Skylarks a choice of habitat for shelter and forage. Clearing excess vegetation also benefits the plants by allowing light and warmth to reach freshly dropped seed after flowering and enables the less dominant species to compete with more vigorous plants.
As well as habitat creation, Sky Garden also had to overcome a number of challenges posed during the project, including weight loadings, system build-up, sustainability, logistics, installation to programme and within cost budget.
The sustainability of the living roof system was a challenge, restricted to a relatively shallow build-up of soil compared to the surrounding natural meadows at ground level, but still needing to create flourishing flower-rich grassland on the roofs. Sky Garden achieved this balance by installing a buried drip-line irrigation system within the substrate, so that the plants would not only establish fully but survive any future prolonged drought conditions. Optimising water efficiency was paramount and this was achieved by the integration of moisture sensors within the substrate, to monitor water levels and only allow irrigation to be switched on when needed by the plants.
Logistics had to be carefully planned and executed, due to the volume of deliveries and large quantity of materials being shipped to site. The substrate for Pinewood was engineered by Sky Garden at their own production facility in Worcestershire and brought in on loose-tipped deliveries for mixing and loading into hoppers before craning up onto the roofs.
The green Roofs totalled in excess of 12,800m² and a variety of materials had to be delivered ‘just in time’ as each roof became available for greening.
Much to the delight of everyone who was involved the project, the Skylarks have bred successfully on the phase 1 green roofs at Pinewood, in the first Summer after the roofs were completed in March 2017. This is therefore a landmark project for future developments, not only for phase 2 at Pinewood, but for other UK and world-wide construction projects where planning permission is linked to the enhancement of Ecological value and the protection of wildlife by the use of green roofs.
Sky Garden are proud to be involved in all stages of this immensely significant project, where the creation of a wildlife habitat on otherwise barren rooftops, has shown that a sensitive and ambitious building strategy can lead to real benefits for people and nature.