(Updated 8/26/2024)

“Going green” and being eco-friendly is both environmentally and financially favorable, so it is no wonder green roofs are becoming more and more popular. A sustainable, green roof is partially or completely covered with vegetation. It protects the building from moisture, leaks and water runoff. A green roof is also a more energy efficient roof than conventional roofing systems. It significantly decreases energy consumption, has a longer service life, and therefore requires less overall maintenance. It is both environmentally and economically more beneficial.

You can build your own green roof, and here is how. First, you’ll need to consider whether building a green roof is going to be a good choice for you.

Is your roof suitable for a green roof?

The most important thing to do before starting any work on your roof is to check whether it is even possible. Determining whether your roof is suitable for a green roof involves assessing various factors that contribute to its structural integrity and environmental conditions. There are certain characteristics your roof must have, including the following:

• Durability – the structural integrity of your roof must be evaluated to ensure it can support the additional weight of soil, plants, and water without risking damage. Building codes and regulations should also be considered, as some areas have specific guidelines for green roof installations. Also, consider how much plant life you will put on it and everything else that goes along with those plants: there are at least three layers in a green roof. The overall weight of the roof can vary; for this reason, it’s best to consult with a structural engineer or green roof professional who can give you a professional assessment. You can also seek help from if you need to remove or trim nearby trees in order to renovate your roof and make it durable enough for a green roof.
  

• Slope – the angle and design of the roof play a crucial role in its suitability; flat or low-slope roofs are generally more favorable for green roofs than steeply pitched ones. If you have a flat roof, or one with a small slope, it can retain too much water, and if the slope is too steep the greenery can slip off. The ideal slope is up to 40 degrees.

Constructing a green roof

Now that you’ve determined your roof is suitable for being converted into a green roof, you can get to work. Here are the key steps you’ll need to take to ensure that it is functional and long-lasting.

Proper drainage

Proper drainage systems are essential to prevent water pooling and potential leaks. When you have inspected your roof, and all of the required aspects and characteristics are in check, you can get to work. The first thing to do is to install a proper drainage system, if you don’t already have it installed. This is nothing complicated. You just need to make sure to have gutters all around the roof, and a downspout on the lowest part of the roof, so that the excess water can flow into it and escape.

3. Waterproof your roof

You will need to put a waterproof layer all across the roof. It was mentioned before that a green roof has several layers, and this one has to be the first one (the bottom one). Ideally, your roof will have a single waterproof sheet covering the whole surface. On top of that one, you should install another layer that will function as drainage, and that will allow the water to go into the gutters. You can use different materials for this, but if you are not sure, you can always ask professional roofers for advice. Some commonly used materials are pumice, clay, mulch, and polymers.

4. Add soil

The soil for green roofs needs to be a little different than the one you would normally put in a garden. Since it is on the roof, it needs to be lightweight, low in nutrients and low in organic content in order to prevent unwanted vegetation. Considering this, you should avoid topsoil and peat. The best thing to do is to mix organic and inorganic materials (crushed brick, clay), so that there is more than half of inorganic materials in the mix.

5. Choose and add plants

Make sure to choose tolerant and resistant plants that can endure extreme weather conditions. Not every plant would survive the extreme exposure to the elements on the rooftop. Some of your best options are succulents (such as cacti), sedums (such as biting stonecrop), or some wildflowers (aster, yarrow, or sea thrift). You can also check with local nurseries or university agricultural extensions for advice about suitable plants for your region. If you want to add color to your green roof, daylilies and lavender are good choices for many. Finally, when choosing plants take sunlight exposure into account, as different plants will require varying levels of sunlight to thrive.

6. Watering the roof

In the beginning, while they’re still growing, the plants will need to be watered a bit more frequently. But later, when they are fully grown, you will not have to worry about them as much. The rain will do most of the watering work. Just make sure none of your gutters are blocked in any way, and that the drainage is functioning properly. Otherwise, you can have some serious water retention problems and damage to your house.

The Benefits of Green Roofs

Creating a DIY green roof can be a rewarding and environmentally friendly project that benefits both homeowners and the planet. By transforming a traditionally unused space into a vibrant green oasis, individuals can improve insulation, reduce energy consumption, and manage stormwater effectively. Additionally, cultivating plants on rooftops can enhance air quality and promote biodiversity. A DIY green roof not only offers aesthetic appeal but also contributes to urban ecology, helping to combat the heat island effect in cities. With careful planning, appropriate materials, and the right plant selection, anyone can successfully embark on this sustainable initiative and enjoy the numerous advantages it brings.

About the Author: 

This article was written by Matt, a writer and an editor for Georgia Roof Pro. He covers local topics, housing, sustainability and roof technology themes.

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