Location: Makarau, North Auckland, New Zealand
Client: Renée Davies, Unitec
Landscape Architect & Living Roof Design: Renée Davies
Roof Contractor: Self-build
Living Roof Type: extensive, plywood roof
Development Type: Residential sleep-out
Living Roof Brief: The main purpose for this living roof was to create an attractive roof to a sleepout (guest bedroom) building, as it is directly visible from the second storey of the house. Also, it was needed to improve the insulation of the building. Biodiversity was also a component, as it is directly adjacent to an area of native bush/forest, so we wanted to provide a vegetative link both visually and biologically. One of the key drivers in creating the living roof was to trial a particular living roof product and to have a project which highlighted how easy it is in a New Zealand context to create a living roof in a residential setting.
Living Roof Design: Substrate consisted of 20% expanded clay balls, 20% pumice fine grade, 20% pumice large grade, 40% sterile compost
Construction technique in order from bottom to top:
plywood roof (2 layers of 9mm plywood glued together),painted surface of waterproofing paint,timber edge (6x2”),layer of polythene pond liner over plywood and laid up sides of timber edging,Maccaferri flexible plastic drainage layer (versidrain 25P) which has small water retention cells,Layer of geotextile fabric50-70mm layer of substratePlants (selection of native and exotic highly drought tolerant varieties and `low growing with a mix of textures and colours– I wanted a tapestry matt-type effect carpeting the roof)
Living Roof Plants:
Sedums: Sedum ‘gold mound’, Sedum sprium ‘tricolor’, Sedum dasyphyllum and various other sedum species that I’m currently trying out.
New Zealand native plants: Raoulia australis, Raoulia hookerii, Raoulia parkii, Plantago masoniae, Selliera radicans
Others: Portulaca sp., Mesembryanthemum ‘pink ice’ (doing fantastically), Thymus sp. (all the thymes died in the 2010 summer drought – driest summer since 1969 during which time I didn’t water my living roof at all)
Comments: A local trio of magpies use the green roof as a singing stage every morning! This living roof has exceeded my expectations.
Lessons learned: "I don’t refer to them as green roofs any more as a lot of the plants I have used are not ‘green’ and so people’s expectations when I say green roof are for a bright green. I have found that referring to it as a living roof better describes the outcomes and sets people up for a positive response to the variety of colours and textures and seasonal variety found on the roof."
Completion: August 2010