Green Roof Ordinance (now Green Building Ordinance) Overview

What is the Green Roof Ordinance?

  • Buildings over 25,000 sqft must dedicate a percentage of a building’s roof to green, vegetative space.

Why green roofs?

  • Green roofs clean our air, the reduce a buildings energy consumption, they are the best practice to manage storm water, they create biodiversity for bees birds and other insects, the list goes on and on. Please take a look around this site for tons of great research.

The entire roof?

  • Only a percentage. Developers 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 sf 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%
  • So, if a commercial building is 25,000 sqft (5,000 sqft more than a standard Whole Foods) they would have to pay approximately $125,000 (Green Roofs cost an average of $25 per sqft) for these improvements at the time of a normal roof replacement. Buildings do not have to do these upgrades immediately, only at the time of a normal roof replacement, which is about every 15 years.

Will this raise rent or increase taxes?

  • This bill will not raise taxes. It would put the cost on the Developers and building owners.
  • This will not raise rent. These improvements lower long term operating cost of the entire building AND the roof last 2-3 times longer which allows for substantial savings from replacing a roof every 10-15 years. Green roofs are also a best management practice for storm water, allowing buildings to no longer place costly storm water detention systems. These savings should be passed along to the tenant.

Is this for all buildings?

  • Only buildings that exceed 25,000 sqft and residential buildings over 4 stories and greater than 25,000 sqft

What about existing buildings?

  • This affects all large buildings across Denver but there are exemptions. Section 10-304 (B)(1) states: “If an applicant is unable to provide the green roof coverage as required in this chapter, application may be made to the Denver Planning Board for either a complete exemption to the requirement to provide a green roof or to provide a smaller green roof area than would otherwise be required”.

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, developers 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.

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, studies show, lead to a better quality of life and workplace environment.

Does anywhere else have green roofs?

  • Yes! San Francisco and Toronto both have green roof requirements. Other cities also offer incentives for green roofs. Chicago issues permits faster 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!

What else?

  • This bill creates technical standards and a technical advisory group to ensure that the code says up to date and that the rooftops are being built properly and soundly.
  • A building may cover their entire room with solar to be exempt from this building code.
  • Green roofs and solar work in tandem. Solar panels give shade to vegetation and the plants keep the roof cooler.
  • Denver’s EPA building is an average of 80 degrees in the summer, compared to the roof across the street, which measured 170 degrees.

Read the City of Denver Green Buildings Ordinance



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Denver, CO 80202


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