Green Roofs are becoming blase, perhaps, as design moves into living walls. A number of the Solar Decathlon teams have incorporated some form of living wall, think garden on the walls of the house. These walls help cool the house in the summer (reducing solar gain), water management (reduced storm water runoff as they take water from the roof), and have the potential for helping feed the residents (think tomatoes, grapes, herbs …).
Teams with living walls include, among others, “Three Ms”:
The living wall offers a real benefit in rain water mitigation, offering the potential for reducing the burden on storm sewers and, down the line, pollution into water systems. And, the green vegetation provide a cooling effect in summer. And, well, part of the Solar Decathlon is overall environmental impact — the gardens increase greenery, improving the air.
For these superinsulated buildings, the insulating implications of six inches of soil might not be critical, but think about most buildings in temperate climates, which are unlikely to have R-40 or so in the walls. Thus, an additional factor is the interesting question of backfitting opportunities. Vertical walls could be relatively easy backfits onto many buildings and many homes around the world. And, they might offer the potential for significant energy savings along with fresh tomatoes for the dinner table.