Case study: A courtyard roof garden incorporating water features, decked areas and seating, together with soft landscaping and lawns, built as part of a contemporary apartment development on the site
The garden sits above a basement car park, and provides a secure amenity accessible only to residents. Tanking-grade mastic asphalt has been used to line the structure of the garden to prevent water ingress into the garages below.
'We often utilise the roof garden effect especially on small sites where we need to get the car parking in within the site, 'explains the architect's project technician John Wilson.
The designer used a variety of roofing, tanking and waterproofing materials throughout the development, but opted for mastic asphalt specifically for the roof garden in order to protect the car park. 'All the asphalt in the roof garden is buried, so it is done in tanking grade, 'explains Falcon managing director Dermott Cooney.
The company laid 250m2 of the material in three layers to a total depth of 30mm on top of the concrete structure of the basement car park. A geotextile layer separates the asphalt from the soil above to prevent damage to the waterproofing layer from sharp stones.
'Asphalt is a natural material and it comes from below the ground, 'explains Cooney. 'As a result it is in its natural environment when it is buried, and can be covered with just about anything - soil, flagstones, gravel.'
Project: Roof garden, Royles Court, Alderley Edge
Architect: Calder Peel Partnership
Main contractor: Blue Stone
Mastic asphalt contractor: Falcon Asphalt