Green roof

A Guide To Green Roof Construction and Functions

Modern structures strive to follow the standards for sustainable building. It is an exciting prospect to many designers as they come up with many out-of-this-world ideas.

One of the many concepts that truly amazes a lot of people is a green roof. This type of roof is slowly getting more attention as the need for sustainability increases.

What Exactly Is a Green Roof?

It is also known for its other name, which is a living roof. It is the roof area of a building covered either entirely or partially by vegetation.

The place where the plants grow is on a waterproof membrane and a growing medium. Additional layers include a root barrier, as well as drainage and irrigation systems.

Read More: Top 10 Eco-Friendly Building Materials & Applications

Making a Green Roof

It is relatively simple to construct a green roof. It’s all about layering the layers of a green roof system. The development of a green roof requires several crucial components.

Whether it’s for a considerable business-intensive roof or a household green roof, these components are essentially the same.

A green roof needs several components to make the plants that grow on it thrive. These components make up the installation of a green roof system. The layers are (not in order),

  • Drainage barrier
  • Green roof substrate
  • Waterproofing for the deck
  • Geotextile filter
  • Root barrier
  • Vegetation

The Installation Process

There are some phases needed when installing a green or living roof in your building. After considering the design and factors involving the project, the real work begins.

The construction of an intensive roof is almost the same process. It does require some additions to the requirements.

Phase 1: Waterproofing

Whatever the deck you have for your living roof, you still need to waterproof it. The usual material for waterproofing is Ethylene Propylene Diene Terpolymer or EPDT. Ethylene and propylene, the two main components, are from oil and natural gas.

EPDM can fully adherent, mechanically fastened, or ballasted, with liquid adhesives or specially formulated tape to seal the seams of the roofing system.

If you find it difficult to transport equipment for the installation, consider installing Acudor roof hatches on your roof area.

It will provide a safe way of access, but it will also give a level of convenience for the people involved in the regular maintenance of the area.

Phase 2: Root Barrier Installation

Root barriers are a type of protection that some green roof constructions may require. Root barriers provide an impenetrable barrier for the roof membrane against the root and rhizome systems that many vegetation kinds have.

Growing plants other than sedum on a semi-intensive or intense green roof may require root barriers frequently.

Phase 3: Drainage Membrane

After installing the root barrier, you may now roll out the green roof drainage membrane throughout the length of the roof. If you’re using our 20P Drainage and Storage membrane, make sure the cavities face up so that water may gather.

If in doubt, double-check that the bonded geotextile filter fabric is on the membrane’s top side. Cut the membrane to fit your needs.

An important thing to note, if the membrane you’ve chosen doesn’t have an incorporated geotextile filtering layer, you’ll need to add one now. You can link the cavities by overlapping the ends of two rolls of the membrane. Allow at least 100mm of overlap between the geotextile elements.

Read More: Sustainable Homes | Eco-Friendly House | How to Build A Sustainable House

Phase 4: Substrate

Most green roof substrates include recycled secondary aggregates (such as crushed brick) and an organic component (soil/compost), combined in varying ratios for distinct green roof substrate mixes. Extensive Green Roof Substrates uses a Sedum mat, Sedum plug plant, or wildflower planting on shallow green roof systems (200mm depth).

Larger plants, such as shrubs and trees, require Intensive Green Roof Substrates. You may also refer to intensive green roofs as “roof gardens.” Semi-Intensive Green Roof substrates come in various hydraulic conductivity values, making them suitable for use in multiple climates.

Podium Green Roof Substrates, on the other hand, are for landscaping projects that do not require a lot of weight. Its high sand content makes it an ideal growing medium for a variety of plants.

Phase 5: Vegetation

At this stage, you may now plant the seeds you want to grow. On a green roof, you can raise a wide range of plants. Grasses, mosses, and sedum are common green roof plants.

Wildflowers can be an attractive option for attracting wildlife. Because this alpine plant can withstand the changing weather conditions, sedum green roofs are among the most popular solutions.

Green Roof Irrigation & Drainage


A drainage layer for your green roof is a necessary component of your green roof. Drainage is essential in a green roof because it must handle enormous amounts of water while still delivering enough water for the green roof to grow. The utilization of HDPE membrane is common for the green roof drainage layer.

These can include water-collecting cavities or cups. Water is stored in these small reservoirs until needed, at which point plants pull it up. The HDPE membrane has pores that allow excess water to pass through, such as from heavy rain. The water then goes down to a drainage space below, where there is safe drainage through the outlet.


Irrigation is a requirement for intensive roofs in commercial and non-residential constructions. This reason is that healthy plants need a consistent supply of water and nutrients. Plant roots on an intense roof type might be more profound, and they are also exposed to the elements directly.

Drip irrigation systems, which deliver water and nutrients beneath the surface, are frequently used in intensive green roof watering. It is usually more effective than a sprinkler system.

Read More: What Is Lean-to Roof | Lean to Roof Design


Sustainability is gaining a lot of traction lately due to the increasing demands to solve global warming. As the industry evolves to a more practical and innovative approach to construction, much more modern buildings will soon have a green roof. More integration with nature will likely surface as things progress.

If you seek to construct a green roof for your establishment, never entrust it to a DIY. To ensure that you get the worth of what you spend and to avoid extra cost and damages, make sure to hire a professional roofing contractor for the job. They can offer you better options and make sure that the job is well done.


What is a green roof?

A green roof is a roof that is partially or completely covered with vegetation, planted over a waterproof membrane. It is designed to provide environmental benefits such as stormwater management, energy savings, and improved air quality.

How are green roofs constructed?

Green roofs can be constructed using different methods, depending on the type and size of the building, the climate, and the desired vegetation. Some common components of a green roof include a waterproof membrane, a drainage layer, a growing medium, and vegetation.

Are green roofs expensive to install?

Green roofs can be more expensive to install than traditional roofs due to the additional components and labor required. However, they can provide long-term cost savings in terms of energy savings and reduced maintenance costs.

How do green roofs contribute to sustainability?

Green roofs contribute to sustainability by providing environmental benefits such as reducing stormwater runoff, mitigating the urban heat island effect, and improving air quality. They can also help reduce energy consumption and provide habitats for wildlife.

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