Green Roof Typical Maintenance Requirements
Reporting Requirements
An initial installation certification (as-built) stamped by a Professional Engineer (P.E.) registered in the state of Wisconsin shall be submitted to the City Engineer upon completion of construction. The as-built shall be of sufficient detail to show the system was constructed and is functioning as designed. It shall include a statement by the certifying P.E. along with a marked-up drawing (if applicable), infiltration observation, and photograph(s).
An annual report shall be submitted via email to City Stormwater Management staff. The report shall include records of all inspections and maintenance performed for the year. Inspections shall be done every calendar year, with reports being submitted by June 1 of the following year.
Maintenance Provisions
The owner shall maintain all components of the green roof system located onsite. Installation and maintenance shall be in accordance with the manufacturer's guidelines as included. Any alterations to approved Green Roof System shall be approved by the City Engineer. Owner shall maintain records of installation, inspections, cleaning, replacement, and any other maintenance all in accordance with Chapter 37 of the Madison General Ordinances.
Inspection frequency
During vegetation establishment, green roofs shall be inspected at least twice a week. Water as needed. After vegetation has been established, green roof system must be inspected at least four times annually (at least once each season) and after every storm or melt event exceeding 1 inch. Additional inspections shall be completed after major weather events including but not limited to high winds and periods of drought.
General Inspection
- Inspect pipes, outlets, and overflows.
- Inspect structures for cracking, erosion, and deterioration at least once each year.
- Remove sediment, trash and debris as needed. Any clogs or blockages shall be removed as needed. Dispose of waste materials in accordance with local regulations.
- Inspect the green roof for potential issues which may include displaced soil, weeds, plant health, pest control and roof drains.
- Repairs must restore the component to the specifications of the original plan.
- Snow should not be moved or piled on the roof. De-icing materials should not be used on the green roof.
Vegetation Inspection
- It is strongly recommended to work with a landscaping professional to develop a site specific plan and determine the appropriate frequency and timing for vegetation maintenance. Different parts of the green roof may require different maintenance procedures due to microclimate conditions.
- Vegetative cover shall be maintained at 85%. Dead vegetation and bare soil areas shall be addressed as soon as practical and in accordance with the original specifications.
- Pruning and trimming of vegetation shall be performed on a regular schedule based on site specific conditions. Trimming, if needed, should be done using a string trimmer. Mowing with other equipment can damage the roof.
- Review and record plant health, density, and diversity.
- Periodically check soil depth and moisture levels across the planted area. Add growing media to the system as needed to maintain design depths.
- Use integrated pest management practices to minimize use of pesticides. Only use products and methods acceptable to membrane roofing manufacturer.
- To prevent the spread of weeds, it is recommended to do visual inspections every other week during the growing season and pulling any weeds before they go to seed.
- Look for and remove debris and dead vegetation. Minimize disruption to remaining vegetation when removing unwanted growth.
- Restoration of plant material shall be by plugging, not seeding alone.
Access and Safety
In elevated environments, maintenance workers shall use appropriate fall protection and have proper training using these measures. Fall protection measures should be inspected annually.
Mitigate fire risk by removing dry/dead vegetation regularly. Keep fire breaks around the perimeter of the planting bed clear of rubbish. Increase inspection during long dry spells and irrigate if needed.
Drain Time
The green roof facilities shall be deemed to have failed if standing water is evident 72 hours after the rainfall event has ended. Ponding beyond 72 hours may result in odor, water quality, and mosquito breeding issues, vegetation loss, drain clogging, and damage to the roof. If the system has failed, the soil and plantings in the affected area shall be replaced to ensure proper infiltration and seepage into the underlying drain tiles.
Irrigation
- If the irrigation system is present, it should be turned on after the last frost in the spring and turned off before the first frost in the fall.
- In the fall, the irrigation system should be blown out and drained.
- Do not water the green roof between October 15 and April 1, unless temperatures are above 55 degrees Fahrenheit. If temperatures are unseasonably warm, manually water the green roof and take care to drain the system at the end of each watering.
- Consult your green roof manufacturer or landscaping professional to determine your irrigation duration and timing. Adjusted as needed.
- A typical irrigation schedule for native vegetation roofs in the midwest during the establishment phase, is run 2-3 times daily for 5-10 minutes each cycle so that the soil remains damp.
- Once the roof is established, run no more than once daily for 5-10 minutes each cycle.
- Use a water sensor to minimize water use and monitor soil moisture.
Storm Sewer System
The owner shall maintain all components of the storm sewer system located onsite.
Installation and maintenance shall be in accordance with the manufacturer's guidelines. Any alterations to the approved storm sewer shall be approved by the City Engineer.
At a minimum, the storm sewer system shall be inspected annually and cleaned as needed to maintain design capacity.
Owner shall maintain records of inspections, cleaning and replacement of the storm sewer system all in accordance with Chapter 37 of the Madison General Ordinances.