Portland’s Ecoroof policy stipulates that new buildings with a net building area of 20,000 square feet or more must have an ecoroof that covers 100% of the building area (with exceptions). At least 50% of the ecoroof vegetation must be an evergreen species. The vegetation should be hardy and achieve 90% coverage within 2 years of planting. The roof must reduce annual runoff volume by 50%. The roof must have at least 4 inches of growing media. Previously, Portland provided grants for green roof installations to help manage stormwater.