Extensive green roofs include drought tolerant plant species such as succulents, grasses, herbaceous perennials, wildflowers, alpines and bulbs, grown in a shallow layer of lightweight growing media.
Applicable to both new build and retrofitting and designed to replicate the benefits derived from open green spaces, extensive living roofs are virtually self-sustaining; requiring minimal maintenance (typically once or twice a year) and, in the vast majority of projects, no irrigation.
Blackdown tailors roofs to the particular needs of each project, however 4 ‘typical’ examples are introduced below:
NatureMat® - for Instant Greening
NatureMat® is a composite vegetated mat consisting of a biodegradable base layer, a specially formulated substrate layer and a 90% mature plant cover comprising 6-8 species (predominantly Sedums) randomly sown and grown to maturity in our fields in Somerset. Laid onto a Blackdown growing medium and drainage layer, NatureMat® is particularly suited to pitched or curved roofs.
Plug Planted System - for Species Diversity
A diverse selection of hardy succulent plug plants, supported by 70mm of Blackdown's extensive growing medium and 25 mm drainage layer, provide an attractive plant cover with a range of colours, shapes, heights and flowering times and periods. With over 50 available species, specific colour-related themes, maximum winter aesthetics, varied flowering period, custom design etc can be achieved. A variety of wild flowers, herbs, grasses, alpines and bulbs can equally be incorporated; varying the substrate depth to suit (70 -150mm)
View Blackdown's Plug Planted System
Note: To increase biodiversity potential, choose to include wildflower species (up to 30 species available) in our Nectar Stream roof build-up.
Featherweight System - for Low Structural Loadings
For roofs that have limited structural capacity; a more limited range of Sedum plug plants, capable of flourishing in 45 mm of Blackdown's extensive growing medium, has been established following extensive research trials. Affording the ecological benefits of plug planted green roofs, the thin soil layer minimises the loads imposed by the green roof on the building's structure.
Hydroplanted System - for Cost Savings
A mix of Sedum cuttings, seeds, tacifier and fertiliser are applied, through hydroplanting, onto the prepared Blackdown growing medium and drainage layer. The plant cover will germinate and grow (typically over 1 to 2 growing seasons) to deliver the long-term benefits of a green roof. Particularly suited to restricted budgets and large roof areas.
