The cost of a green roof installation is $10 to $35 per square foot or $15,000 to $70,000 total on average.
Choosing to go with an extensive roof can save a ton of money upfront and in the long run. Recover Green Roofs out of Boston determined that intensive roofs cost anywhere from $20 to $200 per square foot, while the most cost-effective extensive roofs are closer to $10 to $50 per square foot.
Professional green roof installation costs between $5,000 and $70,000 for your project, based on your roof size. Roof size, access, and plant selection drive costs, and deeper soil systems require more materials and labor. Plan your budget for add-ons like assessments $500 to $2,000, permits $200 to $1,000, and irrigation $1,000 to $5,000.

Buyers typically pay for extensive green roofs with a combination of substrate, plant mats, waterproofing protection, drainage, and installation labor. Main cost drivers include roof size, roof structure, plant selection, drainage and irrigation needs, and regional labor rates. The following sections provide practical price ranges in USD to help set a budget and compare options.
Cost-Saving Tips for Green Roof Installation Although green roofs can be an expensive investment, there are ways to save money without compromising quality: Opt for an Extensive Green Roof: These roofs are more affordable while still providing significant environmental benefits. Consider Modular Systems: Pre-planted modules can reduce installation time and costs compared to custom planting ...

Maintenance costs for either extensive or intensive green roofs range from $8 to $11 (around Rs 650-900) per square metre.Also, green roofs require a proper drainage system to make sure there is no leakage. That kind of drainage system can only be put in at the planning stage itself.
This study uses data collected from an experimental green roof plot to develop a benefit cost analysis (BCA) for the life cycle of extensive (thin layer) green roof systems in an urban watershed. The results from this analysis are compared with a traditional roofing scenario.