BASICS OF GREEN ROOFS AND GREEN WALLS

Green roofs, which are vegetative layers on top of a roof, provide many benefits, including producing oxygen, cooling and insulating, energy savings, reducing storm water run off, protecting a building from the elements, as well as providing stress-reducing green spaces ‘in the sky’ for people to enjoy and use.

Green roofs can be as basic and simple as a few inches of ground-cover to a complete park-like setting with plants, trees and recreational space for people to use.

What Should a Business Know if Considering the Installation of a Green Roof?

• Consider the load capabilities of the building. Green roofs can add substantial weight to the building. Review engineering specifications to understand how much weight the roof can hold when stressed with weather events including snow, ice, and rain pooling.
• Consider the use. When designing the space, determine whether that space will be used by people to visit and enjoy, will only be viewed from windows, or will be used for functional purposes related to energy and water.
• Consider the location and climate of the building. The look and performance of the green roof depends on the climate, the amount of sun/shade the roof gets, as well as other factors that exist such as glass reflection from other buildings. Look at all those factors before choosing the placement of a green roof and determining its plant make up.
• Consider irrigation and drainage. Drainage is key in making sure that rooftop gardens do not become pools. Rock gardens are commonly used in situations where irrigation cannot be provided and temperatures are determined to be too extreme for a green roof environment. 

How Much Does a Green Roof Cost?

Costs vary greatly for green roofs based on design and building elements, but a ballpark price for basic green-roof installation ranges from $10-$25 per square foot with maintenance costing $1.25 a square foot per year. 

Green walls are becoming increasingly popular because they are a dramatic design feature and one that also has benefits like creating oxygen, dampening the noise in a space and making clients feel more relaxed. Green walls can be designed into indoor lobbies, outdoor courtyards and the sides of high rises. They are incredibly beautiful, but they also need to be designed in a way to allow for the right growing conditions.

Considering Installing a Green Wall? Here are a Few Additional Things to Consider.

• Water is obviously necessary for a thriving green wall, so you need to think about the watering system; whether it will be a spray system or irrigation.
• Lighting is a consideration whether the wall is indoors or out. Indoor green walls often need supplemental light if they are placed in low light areas.
• Plant selection is important. A horticulture expert should advise you on the proper plant selection for the light, water and weather conditions of your space.

Green roof photo courtesy of John Mini Distinctive Landscapes.