Notes from Designing Living Roofs – Part III
In previous posts, we have looked at the addition of a green roof over a garage at a residence located on a steep slope which provided the clients with a planted space in the front of the house. In a second post, we looked at the implementation of a green roof as a key design component which allows the new residence to blend into a lush landscape.
In this section, we will take a look at the design of a new residence which provides a garden hideaway for the clients. For the 2 Bar Project in Menlo Park, California, the clients came to the project looking for cost effective, energy efficient solutions for their home. They are also avid gardeners and offering the clients additional square footage to plant, as opposed to a traditional roof, was appealing to the clients.
The 500sf roof garden is hidden from view until climbing the main stairway and catching a glimpse of the garden from the second floor bridge. Accessible from the master bedroom,
the green roof includes a recessed roof deck which comfortably seats the family of four. In terms of sustainability, the green roof over the living/dining/kitchen area serves to insulate the house in cool weather, controls solar heat gain and reduces water run-off.
Typical, intensive green roof assembly would have required up-sizing of the roof framing, including additional steel, rendering it cost prohibitive. Instead, an exceptionally lightweight engineering with a shallow 2-6” soil depth for the 2 Bar green roof assembly with sedum plants and river rock edging overcomes this challenge. The garden, designed and planted by Lauren Schneider of Wonderland Garden, has been blooming for two years. Sedum, succulents, aloe, vivums, and ice plants make up the garden which flowers in swaths of white and purple – an unexpected, secret garden in a suburban neighborhood.
2 BAR TECHNICAL INFO
The green roof here includes a layer of plastic coating, a roofing barrier, a drainage mat to facilitate drainage, a capillary mat that holds water and encourages plants to take root, a subterranean drip system, a filter fabric to prevent the soil from clogging, a lightweight planting material (15 pounds per square foot) and the seedlings.