What are we proposing?

  • We are proposing that a percentage of a building’s roof be dedicated to green, vegetative space.

The entire roof?

  • Only a percentage. Builders are also permitted to do a combination of green space and solar in this percentage. Here’s the chart:
Gross Floor Area (Size of Building) Coverage of Available Roof Space (Size of Green Roof)
25,000 – 49,999 f2 20%
50,000 – 99,999 f2 30%
100,000 – 149,999 f2 40%
150,000 – 199,999 f2 50%
200,000 f2 or greater 60%


Is this for all Buildings?

  • Only buildings that exceed 25,000 sqft

What about existing buildings?

  • Existing buildings will be required to install a green roof or combination of green roof and solar at the time of roof replacement. If this would require major structural changes then exceptions would be made.

Why Green Roofs and not Cool/White Roofs?

  • Denver has just updated their building code. Part of that code once included a provision for Cool/White Roofs. During public comments, builders expressed concern that white roofs did not last as long in this climate. Thankfully Green Roofs are just the opposite. Green Roofs last up to four times as long as a traditional black roof!

Do Green Roofs work in this climate?

  • They do! In fact, green roofs can be found in every climate around the world. If you would like to learn more about green roofs in this climate, check out our Documents Page to read the extensive research conducted. Or view our Photo Gallery to see some green roofs already in place here in Denver.

What are the benefits of Green Roofs?

  • The benefits are many! Green Roofs are a Best Management Practice for storm-water management. They reduce the Urban Heat Island Effect through evapotranspiration. This also reduces energy costs. Air quality is improved and noise pollution is lessened. Roof longevity is extended. City beautification is achieved which, study’s show, lead to a better quality of life and workplace environment.

Does anywhere else have Mandatory Green Roofs?

  • Yes! San Francisco and Toronto both have green roof mandates. Other cities also offer incentives for green roofs. Chicago has issues quicker permits if you incorporate a green roof. Washington DC gives you a rebate per sqft of green roof and their storm water regulations essentially make green roofs the only option!