Green Infrastructure: Green roofs consist of a series of layers that create an environment suitable for plant growth without damaging the underlying roof system. Green roofs create green space for public benefit, energy efficiency, and stormwater retention/ detention.
Green roof construction can be complex and involve many different trades working in a small space. A pre-construction meeting is recommended prior to beginning any construction on the roof to ensure construction sequencing will maximize efficiency and minimize conflicts between the various trades that need to access the roof. The meeting should include all green roof related installers and designers. Installers present at the meeting should include roofing, green roof, irrigation, leak detection, lightning protection, electrical, glaziers, mechanical, and general contractor, as well any others involved in the green roof project. Designers should include roofing consultant, green roof designer, irrigation designer, electrical and mechanical engineers as well any others involved in the green roof project.
Key factors in determining construction sequencing include the following.
- Do not begin installation until required submittals are approved.
- Staging: stay within load limits throughout installation
- Protect all materials on roof from wind and erosion at all times
- Perform leak detection test after installation of membrane and again after all work on roof is done. If there is significant construction traffic on the roof after leak detection, from green roof contractor or any other trades, leak detection shall be repeated.
- Ensure there will be a means to keep vegetation watered during and after vegetation installation.
- Whenever possible, install green roof only after there will be no more traffic by other trades, such as, for example, window installers or mechanical equipment installers.