Paid for by Citizens for a Responsible Denver

The Facts about Green Roofs & I-300

• This citizen’s initiative will be on the November 2017 ballot in Denver.

• The initiative would require ALL Denver buildings over 25,000 sq. ft. to have a percentage of their roof

dedicated to vegetation and/or solar.

Gross Floor Area (Size of Building) Coverage of Roof Space (Size of Green Roof)

25,000 – 49,999 sq. ft. 20%

50,000 – 99,999 sq. ft. 30%

100,000 – 149,999 sq. ft. 40%

150,000 – 199,999 sq. ft. 50%

• All buildings pulling a building permit after January 1, 2018 would be required to have a green roof.

Existing buildings will be required to install a green roof or combination of green roof and solar at the

time of roof replacement and/or major repair.

• Exemptions are very limited and all exempted buildings are required to provide a cash-in-lieu payment

to the Denver Office of Sustainability equal to the cost of constructing the green roof.

• Costs include initial capital costs, ongoing maintenance costs, and lifecycle costs (i.e., green roof

replacement might cost more than conventional roof replacement).

• Not only would this initiative require installation of a green roof, but the ordinance also mandates the

following, among other provisions:

o Root repellant systems

o Anti-shear measures for sloped roofs

o Engineer-stamped reports on wind uplift pressures being designed for

o Leakage testing

o Water retention mats to promote vegetation growth

o Growing media of at least 4 inches

• The initiative is problematic for many reasons including, but not limited to:

o Will raise the cost of housing, both owner-occupied and rental

o Deters future development

o This type of measure shouldn’t be mandated, but rather incentivized

o Hurts economic development and Denver’s ability to attract and retain business

o Denver’s climate is not well-suite for green roofs

o Water usage to keep roofs alive will be extremely high

o Green roofs can be a fire hazard when not maintained

o A one size fits all initiative from two citizens who have little to no experience with green roofs

is problematic

Paid for by Citizens for a Responsible Denver

The ACTUAL Costs and Risks of Green Roofs

Costs of Green Roofs

• Different types of installation costs include initial capital costs, ongoing maintenance costs, and lifecycle

costs (i.e., green roof replacement might cost more than conventional roof replacement).

• Long-term ancillary costs, such as the increased costs of insurance, liability issues associated with

weight, drainage, interior damages from roots, damage to walls and liability to personal injury.

• Annual maintenance for a green roof is typically much higher than for a traditional roof, including:

▪ design fees,

▪ planning and building permits,

▪ permits for lifts and cranes,

▪ demolition or relocation of existing infrastructure on the building and roof,

▪ addition of specific hard infrastructure elements such as furniture, shade structures, decking,

paving, planter boxes or structures to support climbing or trailing plants.

• The installation of a green roof currently costs approximately $25 per square foot of roof.

• The first gallon costs (i.e. cost for first 3.785 liters of water) for extensive green roofs (defined as having

a growing medium depth 6 inches/15 cm or less) range from $28-$35. In comparison, cisterns cost about

$2 to $5 per first gallon treated, and urban trees about $6 to $8 per first gallon treated.

Health and Safety Risks

• Green roofs may pose a fire hazard – in September 2017, a green roof in Seattle caught fire, was very

difficult to extinguish, and endangered building occupants.

• Not all roofs have sufficient structural capacity and require strengthening. There is an increased risk of

roof collapse resulting from a green roof that was not properly constructed, installed or maintained.

• Mold and other environmental hazards as a result of poor installation and maintenance of a green roof

may pose a risk to inhabitants.

Economic Risks

• Possibility of failure to attain the energy efficiency levels claimed by the installation of a green roof.

• Turning a building's uppermost level into a green roof will involve greater expenses up-front, in both the

construction and the maintenance. This will hurt the local real estate industry.

• The cost burden will be handed off to the consumers and exacerbate the housing crisis.

• Building construction and tenants will move to Denver’s suburbs where construction costs and rents are

cheaper.

Paid for by Citizens for a Responsible Denver

I-300 is WRONG for Denver

In November 2017, Denver residents will be asked to vote on I-300—the “Green Roof Initiative.” This initiative will be detrimental to Denver for years to come.

The Denver Post Editorial Board on March 14, 2017 came out against a green roof mandate saying: “Green roofs should not be mandated by a highly prescriptive law, as supporters of the ballot measure are proposing.”

In a story on March 5, 2017, The Denver Post stated that “Rules would be among most stringent in U.S.” and that “Denver updated its building code last year. The Department of Community Planning and Development was hesitant to pursue a green roof mandate.”

If I-300 passes in November

Denver housing costs will continue to skyrocket. This mandate would drive up building and maintenance costs, which will be passed-on as higher rents and higher housing costs, putting housing further out-of-reach for many families.

New construction and replaced roofs would be required to install green roofs rather than given the option. Green roofs should not be a mandate on all new construction and replaced roofs. We should be given the choice and incentives for those who decide they want to have a green rooftop.

Do NOT gamble away Denver’s future with a harmful mandate that does not allow for any flexibility.

Vote NO on I-300 on November 7th!