With an increase in the popularity of green roofs, there are also general assumptions and misconceptions about these roofs.  

This article busts some common myths about green roofs, with expert input from industry expert Green Roofs. 

Myth no. 1: Green roofs are a new and experimental part of the green trend. 

Green roofs have been around for centuries. It’s the execution of them that has become more technical lately, allowing for thinner and lighter roof profiles. 

This green roof has been protecting this German residence since the 1940s, more than 70 years ago

Myth no. 2: A green roof is only for a green building. 

Green building certifications may award points for the installation of a green roof, but the environmental benefits are undeniable. However, even building without a specific eco objective can benefit from the aesthetic and economical aspects of having an extended garden space. 

Myth no. 3: Green roofs may look nice, but they can cause structural problems and leakage. 

Arguably one of the most cited concerns, despite there being no evidence to suggest that green roofs are more susceptible to leaking. 

A leaky roof is independent of whether it’s a green roof or a traditional roof. It has to do with the installation and design specification of the structure, and all roofs must have a proper waterproofing membrane, green roofs included.

Some studies suggest that the longer lifecycle of a green roof is due to the protection of the waterproof membrane from ultraviolet sunlight. The plants and substrate act as a natural barrier to weathering. 

Newly constructed homes: These must meet the requirements of the designed loads of a green roof. If this is addressed from the design phase, there should be no problem meeting the structural requirements.  

A properly designed green roof will also have a root barrier to stop plants from trying to root too deep. 

Retrofitted green roofs: These roofs require careful consideration. Requirements will depend on what part of the country the building is in, and what kinds of loads the home was originally designed to sustain (snow, wind, rain etc.). 

Beyond aiding in achieving green certifications, green roofs add valuable garden space to buildings.

Myth no. 4: Green roofs are difficult and costly to irrigate. 

Many people think that a green roof has to be planted with sedum or other succulents because it’s impossible or prohibitively expensive to irrigate a green roof.  

The reality is that all green roofs require irrigation in the beginning while the roots of the plants are establishing themselves, with the exception of pre-grown mats made off-site. Water-storing plants are so popular because they are beautiful and hardy enough to stand up to the tough conditions of a roof. 

However, sometimes combining these with other types of vegetation, such as native grasses, can be a good way to introduce more diversity and increase the aesthetic charm of the roof. Intensive roofs, or roof gardens, are the perfect example of this, with some even featuring bushes and trees. 

Myth no. 5: You can just put some dirt on your roof to make your own green roof. 

Stop! Don’t do it. A well-designed green roof is made of much more than good potting soil. Often it doesn’t even include soil, but instead calls for perlite or other porous lightweight materials. 

The structure of the home needs to be analysed to see if it can handle the load of a rain-soaked green roof. The specific climate of the site needs to be considered, and the plant selection and drainage systems need to be designed.

A properly designed roof that meets the structural requirements and has a properly installed waterproofing membrane, is unlikely to leak.

Myth no. 6: A green roof is just too expensive and complicated. 

Many people are intimidated by green roofs, due to not knowing where to start or how much it will cost. Cost estimates are highly variable, depending on whether it is an inaccessible sedum roof or an accessible roof garden.

The warranties on the building products used in a green roof are similar to these for all the other building products. They must be installed according to the manufacturer’s specifications, by a qualified professional.

Every green roof installation should come with a service contract to address annual maintenance. This should be part of the initial design and installation, with a two-year and a five-year plan included, or perhaps an even longer plan in certain circumstances. The extent of that maintenance will depend largely on how the green roof is used.  

While the lifespans of residential green roofs are still largely undocumented, some professionals say they can be double or more the lifespan of a traditional roof. The green roofs of Rockefeller Centre in New York City, for example, have the same waterproofing membranes that were installed in the 1930s. 

Issue: Myths and misconceptions about green roofs. 

Solution: Addressing six of the most common myths about green roofs in residential homes.  

Full thanks and acknowledgement go to https://www.greenroofs.co.za for the information in this article.