Best Products for Green Roof Construction

Best Products for Green Roof Construction

Green roofs—also known as eco-roofs or living roofs—are gaining popularity worldwide as an effective and aesthetic means of increasing energy efficiency and reducing environmental impact.

While these innovative greenspaces are undoubtedly cool to look at, incorporating vegetation into one’s building structure serves a wide range of functional purposes, such as absorbing rainwater, providing insulation, creating a wildlife habitat and growing produce for urban gardens.

There are also physiological benefits—according to Living Roofs, “access to green space can bring about direct improvements in a person’s heart rate and blood pressure, and can aid in general well-being.” In other words, if you’re contributing to the green roof movement in any capacity, you’re basically improving lives. Kudos! And if you’re not, well, here’s some info on how you can get started.

Extensive vs. Intensive Green Roofs: Which One Is Right for You?

Green roofs are characterized by depth of medium and required maintenance, which means the type of space you decide to build will depend largely on the space and amount of upkeep you’re able to perform.

If you’re looking for a smaller, lower-maintenance space, an extensive green roof is probably your best option. Extensive green roofs are designed to be self-sustaining, without the need for a permanent irrigation system. The vegetation medium for an extensive green roof is typically six inches or less, which makes it ideal for species like sedum, delosperma, euphorbia and sempervivum.

Intensive green roofs contain a wide variety of vegetation, requiring professional maintenance and advanced irrigation systems. The vegetation medium for an intensive green roof design is usually six inches or more, which lends itself well to urban gardens and park-like landscapes that support larger-scale vegetation, such as trees, shrubs and grasses.

Basic Green Roof Construction Design

While green roof design varies by space, landscape and design preference, all green roofs share eight basic elements:

  • Structural Roof Support
  • Vapor Control
  • Thermal Insulation
  • Roofing Membrane
  • Drainage Layer
  • Filter Fabric
  • Growing Medium
  • Vegetation

Here, we will focus on the right products to use for two of the most critical elements of a green roof—the drainage layer and filter fabric. Because the drainage layer is what allows water to flow from the roof, having the right fabric is key to protecting your structure during heavy rains and storms. And for waterproofing, we’ll also examine the importance of installing a root barrier—especially when it comes to intensive green roof design.

For Adequate Green Roof Drainage, Choose Enkadrains & Enkamats

Enkadrain® is a three dimensional drainage board consisting of geotextile fabric that reduces hydrostatic pressure in soil by allowing water to navigate to the polymeric core. It’s designed to preserve the surrounding soil and keep the structure dry by guiding the water to another discharge system. Enkadrains can be a lightweight alternative to traditional sand and gravel drains.

Because there are so many different options within the Enkadrain product line, we’ve put together a quick-reference guide to help you determine which product is best for your sloped green roof.

Roof Gradient

Product Solutions

Product Recommendations

Roof Gradient

Flat <1° (<2%)

Product Solutions

Lifts the growing substrate and plants above the ponding water

Product Recommendations

Enkadrain 9118, Enkadrain 9120, Enkadrain 9125

Roof Gradient

Low 1-5° (2-9%)

Product Solutions

Effectively conveys runoff to roof drains and EnkaRetain & Drain is designed for high water storage capacity

Product Recommendations

Enkadrain 9010, Enkadrain 3611, Enkadrain 3615, Enkadrain 3811, EnkaRetain & Drain 3111, and EnkaRetain & Drain 3211

Roof Gradient

Steep 5-20° (9-36%)

Product Solutions

Slows down runoff, allowing time for rainwater to soak into the growing substrate, it retains water and compensates for higher runoff, and minimizes sliding on steep slope roof (when installed upside down)

Product Recommendations

Enkadrain 3601, Enkadrain 3801, Enkadrain 7910, EnkaRetain & Drain 3111, EnkaRetain & Drain 3211

Roof Gradient

Very Steep >20° (>36%)

Product Solutions

Secures drainage layer to prevent sliding

Product Recommendations

Enkadrain 3601, Enkadrain 3801, and Enkadrain 7910

Roof Gradient

Any Slope

Product Solutions

Enkamat green roof drainage mats permanently anchor plant roots on steep slopes or in high wind conditions

Product Recommendations

Enkamat

Root Barriers for Green Roofs

Installing a root barrier will help protect your green roof waterproofing membrane from damage—especially if your green roof system is intensive. Root barriers are available in multiple thicknesses to accommodate the different needs of your garden. Below is a breakdown of which root barrier mil thickness to buy for your structure.

Plant Type

Recommended mil Thickness

Plant Type

Sedums and Shallow root plants

Recommended mil Thickness

20 mil will protect against roots with minimal penetration pressure

Plant Type

Perennials and Grass

Recommended mil Thickness

30 mil will protect against slightly more aggressive plants that tend to grow larger than moss

Plant Type

Bamboo and Trees

Recommended mil Thickness

A 40 mil or thicker is recommended for gardens with aggressive roots that can cause serious damage

Bring Your Green Infrastructure to Life with Americover

Green roofs and green infrastructures can be life savers in terms of energy efficiency, air quality and even state of mind, but they can quickly become the exact opposite if installed incorrectly or if the contractor doesn’t use high-quality materials.

Americover has been trusted by contractors for over 25 years and counting. Our team of geomembrane and geotextile experts can help you find the best green roof solutions for your project and have the materials delivered straight to the jobsite. Contact us today for a quote.

For Contractors and Distributors

We offer special pricing, volume discounts, short lead times and a dedicated account manager who will work with you to get exactly what you need. If you would like to speak with a representative, contact us at 833.261.6501.