There are many reasons why green roofs are a solid option. They provide a wonderful natural appeal, they help with water retention and drainage, and they provide good insulation. On top of all that, they help to preserve the environment and provide places for plant life to grow and flourish. Green roofing is a big part of sustainable building. Here is a run down on the construction engineering behind green roofs.


No matter the roof type, from wood to metal to concrete decks, green roofing can be installed. All it needs is that the roof can bear the load and be waterproof. That means your roof can become a green roof at any time should you wish.


Green roofs attract and create a lot of moisture, so your roof has be prepared to handle that. As well, the roots can cause damage to the waterproofing, so steps should be taken to prevent this. That means using approved waterproofing products that will keep your home free of moisture and protect against root incursions. Not just the surface needs to be protected. Every part of the substructure should be water and root-proofed. That includes the joints, roof edges, and upstands.

Roof Parapets and Other Components

The roofing professional should precisely measure the upstand heights so that they are at least 6 inches. This goes for any adjacent building parts. Roof edges must be a least 4 inches. The upstand should be measured from the gravel strip of the green roofing system. To create a tight enough connection, clamps are used. The upstand height can be lower if needed, such as with wheelchair accessible buildings. To prevent water from penetrating the roof, group components such as water connections and building parts together.

Slope of the Roof

Green roofing isn’t just for flat roofs. With newer technology, it is now possible to install a green roof system on sloped roofs, as well as shed roofs, saddle roofs, and barrel roofs. If the roof is over 10 degrees, then there are some special considerations to account for the additional weight and the possibility of erosion, however. The only way a sloped roof won’t work is if the slope is more than 45 degrees. In fact, a slope will help with drainage and irrigation. On a flat roof, it is crucial for the proper water drainage systems to be installed to prevent puddles and seepage.


Always take into consideration the load that the roof structure can handle when installing a green roof system. In your calculations, make sure to account for the water build-up, the vegetation, and the construction components. A standard green roof can weight between 60 to 150 kilograms per square meter. If the roof was initially a gravel roof, then often a green roofing system can be installed without any additional supports since the gravel that will be removed will weigh roughly the same as the new roofing system.


Drainage is one of the most important factors to consider in green roof installation. These systems tend to store up water when it rains, which is then lost through transpiration. Sometimes there is too much water to store, so it needs to be drained effectively to prevent a build up, which can lead to leaks and seepage. Roof outlets need to be monitored for blockages from vegetation and debris, so that the water can freely run off at any time. If the roof has inlayed drainage, then there must always be at least two outlets. With many green systems, there are grids and gullies installed to move excess water away more efficiently.


Installing any kind of roof can be dangerous. When you are planning your green roof system, make sure to account for safety measures that you will need to take.These can include walkways, railings, and other components that will make the job safer for everyone.

A green roofing system is something that almost anyone with a roof should consider. It helps the environment, insulates well, and can give a building a nice natural look and feel.

If you have questions about roofs or if you are in need of roofing services, do not hesitate to contact Central Roofing Company™. You can reach us online or by calling 763-572-0660.

Request Project Information