There are different benefits to enjoy when opting for a green roof. While they help bring the best of property and communicate how much work owners have done on the design, green roofs are also eco-friendly.

Also, they are a good absorber of different damaging factors that can cause damage to the building. For example, green roofs are excellent at absorbing water, CO2, and heat from the sun. Plus, they are a good insulator for the property, meaning they help regulate the interior temperature.

Green roofs are of three major types, depending on the system’s thickness: intensive, extensive, and semi-intensive.

• • • Intensive grass roof (thick): is the thickest of the three types and is made up of about 50-200mm of soil, thick enough to grow different types of grasses, flowers, herbs, and even shrubs. In an intensive green roof, the garden must be accessible as it needs adequate and frequent maintenance. With their enormous weight, intensive green roofs offer better insulation and absorb more water than other options. Also, it is a good option for wildlife growth and can be used as a recreation center. 
      However, it requires a strong roofing structure to carry the heavy weight.
    • Extensive (thin): is low in every aspect, such that it features a shallow soil layer of about 20-100mm and can also absorb little water. Also, the insulation in an extensive system is very low, compared to an intensive system. 
      However, extensive green roofs require low maintenance.
    • Semi-extensive green roof: this stands between intensive and extensive systems but takes many similarities from the extensive system. For example, semi-extensive has low maintenance requirements and the method of construction is much of an extensive system, with a slightly greater depth (100 – 200mm).

Each system has different application areas, with the thick intensive system reserved for special applications. The major issue with an intensive system is the maintenance requirements, rendering it a less ideal option for domestic applications. This doesn’t mean other systems don’t require maintenance but lower maintenance compared to what intensive system requires.

The cost of a green roof differs from system to system. While an extensive system is the least expensive, it is followed by the semi-extensive system, while the intensive system costs much more than other options.

As a guide, while a $60/meter square budget might be ideal for an extensive system, an intensive system might cost up to $250/m2. In addition, factoring in the cost of reinforcing the roofing structure adds to the total cost of installation.

A green roof comprises different layers with the right principles. A diversion in following the standard principles will alter the integrity of the system and the structure. 

In installing a green roof, one necessary principle is the protective layer between the roof surface and soil. Soil is a big threat to the roofing structure, affecting the waterproofing layer when in contact. Hence, there is a need to provide a protective layer separating the roof surface from the soil. 

Also, a green roof requires functional drainage to pass away excess water from the system. This will aid water regulation on the roof and have some touches on the topography of the roof.

Different options are available for the drainage type to provide a green roof. While using plastic eggshell-style drainage is the conventional approach, other natural alternatives have proven effective. 

A gravel-layer drainage system is a good option for green roofs but is condemned for its heavyweight, mounting more pressure on the roof.