Frequently Asked Questions — Recover Green Roofs

Frequently Asked Questions - Recover Green Roofs

What is a green roof?

A green roof (also known as a vegetated roof, living roof, or ecoroof) is a layered system of components including vegetation on top of an existing roof deck. A green roof can either completely or partially cover a rooftop depending on the desired goals of the project.

What are the benefits of green roofs?

From environmental to economic, green roofs provide an array of benefits. The merits of green roofs depend on location, depth of growing media, type of green roof system, and plant variety. Green roofs can double or triple the life of a waterproof membrane, create habitats, insulate a building, reduce stormwater runoff, and help sequester carbon from the air.

Please refer to our Resources & Benefits page for more specific examples of green roof benefits.

What are the different types of green roofs?

Extensive:  The least expensive and lightest type of system that uses 6 of growing media. Sedum (a drought-tolerant plant) is the primary plant used in extensive green roofs because it can grow in just 1 of soil and weigh as little as 8 lbs/ sq ft. After a temporary irrigation system is installed during plant establishment, extensive green roofs often require no irrigation.

Semi-Intensive:  This system uses a mixture of characteristics from the extensive and intensive green roof categories. Semi-intensive systems are typically between 4-12 in soil depth and may contain a variety of vegetation ranging from sedum to grasses and shrubs.

Intensive: This is the most expensive system, as it contains the largest amount of soil depth and provides a wider variety of options for plant selection. The soil depth of an intensive green roof typically ranges from 12-36+. An intensive green roof also has the highest capability to mitigate stormwater runoff and insulate a building.

How much does a green roof weigh?

The weight of a green roof varies and depends on the type of system installed. Durign the design phase, Recover always works with a structural engineer to determine the loading capacity of a roof.

On average, an extensive  green roof weighs between 10-30 lbs/sf, semi-intensive  green roof weighs between 30-50 lbs/sf, and an intensive  green roof weighs between 50-300 lbs/sf.

How much does a green roof cost?

The price of a green roof varies from project to project and depends on these factors: the type of green roof system, the quality of the rooftop membrane, the roofs accessibility and fall protection, the loading capacity, and the ease of material conveyance to the roof.

Price ranges depending on system type:

  • Extensive:  $10-50+/ sq ft.
  • Frequently Asked Questions - Recover Green Roofs
  • Semi-Intensive: $25-200+/ sq ft. 
  • Intensive:  $20-200+/ sq ft.

What services does Recover Green Roofs provide?

Recover is a Design/Build/Maintenance firm, which means we will work with our clients from the design phase, through the material sourcing and delivery, to the installation. After construction, we also provide maintenance services.

Im interested in having a green roof. What is the first step?

Give us a call to speak with one of our Project Managers. Our office number is 617-764-1310. Or, shoot us an email at info [at] recovergreenroofs [dot] com. Once were able to talk and figure out the goals of your project in mind, well move on with structural assessments and design.

What are the main constraints of green roof construction?

There are three preliminary obstacles when planning for a green roof:

  1. Waterproofing: A watertight membrane is a necessary first step for all green roofs. A best case scenario is a new roof or one with a waterproof membrane that was replaced in the past 5 years.
  2. Loading capacity: Recover always uses a structural engineer to assess the amount of weight a building can support during and after construction of a green roof.
  3. Accessibility/Fall protection: Any occupied roof must have proper egress and railing systems in compliance with local and current OSHA regulations.

Perhaps. Rooftop farms are a growing interest around the world, and it is important to address the challenges that come with the excitement. Rooftop farms are the heaviest systems we design, and there are several initial constraints such as the weight capacity, waterproof membrane quality, and safety protection.

After working through the preliminary questions, Recover can begin to design a rooftop farm that works for your specific setting.

Call Recover today to speak with a Green Roof Professional: 617-764-1310


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