Think of green walls/roofs as integral to the building
Jeff Bruce says that the biggest message for architects and builders is that green roofs and walls are not an applique that can be added at the end of the design process. Instead, think of them as integral to the program and to overall life cycle cost estimating for energy use. For optimal value, green design experts for the exterior should be at the table from pre-design through construction administration.
Qualify all components of soil mix
Identify local sources early in the design process. This approach will save time and transport cost once construction begins. For architects and clients, it’s helpful to know the basic elements of rooftop soils in talking with green roof installers and designers. Here are basic recommendations for choosing soil mix components.
Sands: Seek out sands that are the byproducts of local operations such as river-dredging and sand quarrying.
Organic matter:Roof designers can breathe the life back into sterile soils with organic matter such as worm castings (excrement) that has microorganisms to support plant life. This can be mixed with local compost from yard waste (for which Bruce has defined specifications). This mix adds moisture retention and nutrition back into the soil to allow for a better oxygen and nitrogen exchange.