Green Roof Pros and Cons
A green roof is known by several names such as eco-roof or living roof. They have been built on buildings for centuries. Many countries in the world have green roof subsidies or programs that encourage eco-roofs. Scandinavia has long had farm house buildings that have sod covered roofs. Some cities in the US are known for their living roofs such as Chicago’s City Hall building.
Basically a green roof is a roof that has vegetation and a growing medium. It will cost more than a standard asphalt shingle roofing application. Rooftop garden costs also depend on the type of green roof installed. There are several differences among green roofs and some applications that may or may not be defined as a green roof such as a container garden green roof.
The additional costs depend on the substructure of the initial building. They may require additional support as a green roof will weigh more than a traditional asphalt roof. However a roof that already has clay or concrete roofing material may be strong enough to support a heavier roof. The additional cost per square foot has many variables so an accurate cost really cannot be estimated. It could vary by eight to over twenty five dollars per square foot.
Some drawbacks to rooftop gardens are that they cost more to install. Maintenance can also be costly for the more intensive varieties. Some require access for maintenance so that has to be provided which adds to the costs. Of course the weather comes into play. A project in Palm Springs will have different maintenance issues than one in Minnesota that has to endure cold temperatures. An eco-roof is exposed to the seasons just like the garden or lawn, so it won’t stay a stunning shade of green throughout the whole year.
The advantages are much stronger strong. One thing that has been proven is a green roof does reduce heating and cooling costs. They make great insulation. They attract insects and other forms of animals. They help control any water runoff. They also clean up the water that does fall to the ground. They may reduce replacement roofing costs as the green growth protects from the harmful damage of the sun. Of course if covered with sun, they may make the roof very heavy.
There are several different types of living roof. The two basic types are an extensive green roof which does not require as much maintenance. It may need yearly weeding but it is designed to be virtually self sustaining with minimum maintenance.
The second one is an intensive, meaning that it requires more labor and expense to install and maintain. It may weigh more than the extensive roof as it requires a thicker growing medium. They require irrigation, feeding and other maintenance. They are more park like.
If one chooses to build an eco-roof as a new structure or remodeling an existing structure roof you will probably need a building permit in most cities. Some cities encourage roof gardens, and other sustainable design projects, so make sure to check your local regulations to see if there are any tax breaks or other zoning advantages you qualify for.