Living Roofs: What are Intensive & Extensive Green Roofs?

As we begin to adopt new technologies to green up our urban spaces, planners and designers are opening to the idea of greening up more roof spaces. Whether it is the unused flat roof on top of a multi-storey carpark, or the bare rooftop of an old skyscraper, the untapped potential in these “wasted” spaces are arguably ripe for the picking. Therein lies the opportunity to convert these spaces into green roofs, whether intensive or extensive.

When it comes to green roofing, the abovementioned terms intensive & extensive are often bandied about. But how many of us are really able to distinguish between the two kinds of green roofs? In this post, we shall attempt to lay these doubts to rest – here’s a brief comparison between intensive green roofing & extensive roofs. (TLDR; scroll down to the last image)

An extensive green roof on metal deck completed by Belalang outside a meeting room in Johor Bahru.

INTENSIVE GREEN ROOFS are described in the Guidelines for the Planning, Execution and Upkeep of Green Roofs (published by the German Landscape Research, Development and Construction Society, or FLL for short) as “…the planting of shrubs and coppices, as well as grassed areas, even an occasional tree.” and it also mentions that “Regular attention is needed to maintain sites of this type in good order, in particular regular watering and feeding is required“. In simple terms, intensive green roofs allow for the widest range of plants and shrubs to be planted on the roof area, restricted only by the property’s design intent and structural constraints. The inclusion of grasses that are trafficable also allows users to step onto these green roofs for leisure activities such as picnics or strolls.

That said, the substrate needed to sustain these plants are usually deeper, which translates into a massive weight addition to the building’s structure. Deeper growing medium also means that planters have to be specifically created to suit the location of these plants. Lastly, an intensive design is usually accompanied by a high up-front cost (taking into consideration the structural load and creation of planters) as well as incur more substantial maintenance efforts to ensure a thriving green roof.

Intensive green roof at Accapella Residence in Seksyen 13, Shah Alam

EXTENSIVE GREEN ROOFS on the other hand, are limited by their thin built-up and inherent system traits to provide a shorter list of species. The reason for this being that extensive green roofs advocates the lowest form of maintenance, hence the usage of hardy local species that require close to zero attention upon installation. This also means that these roofs are usually located in areas to which the public have limited to no access.

The FLL in Germany classifies extensive green roofs as “… cultivation of vegetation in forms which create a ‘virtual Nature’ landscape and requires hardly any external input for either maintenance or propagation”. Being inaccessible and catering to a narrower range of species for this kind of green roof are tradeoffs to the following attributes:

  1. Lowest form of maintenance due to hardy local plants
  2. Lightweight (As reference, the GaiaMat extensive green roof is 6 times lighter than convensional roof turfing systems)
  3. Lower up-front cost
  4. Able to retrofit different roof types- RC flat roof, Metal decks and even glass roofs.
Extensive green roof completed by Belalang in 2019 using hardy species in PJ, Selangor

To sum it all up, here’s a table comparing both roofing systems, extracted from the Green Roof and Wall Policy in North America – Regulations, Incentives and Best Practices (2019):

We hope this helps to clarify any doubts on what we call Extensive and Intensive green roofing! For enquiries on using our GaiaMat (extensive) or the GaiaTurf (intensive) green roof system, please do drop us a message in the contact form (<< click here).

Green Roof and Green Wall Maintenance During the COVID-19 Pandemic

Even if you’ve been living under a rock, chances are, you may have heard about the on-going global COVID-19 pandemic. In order to prevent the spread of the virus, lockdowns in all forms and names were imposed by governments all over the world. Be it MCO (Movement Control Order) in Malaysia, Circuit Breaker (CB) in our neighbour Singapore, or simply “Lockdown” in many other countries, they share similarities ranging from border shutdowns to closing of economic sectors deemed non-essential.

Fast forward 2 months, as most economic sectors are beginning to reopen in thie CMCO(Conditional Movement Control Order) period, team Belalang too refused to remain idle. Upon obtaining the letter of approval (conditional) from Ministry of International Trade and Industries (MITI) in early May, we have resumed the maintenance of green roof and walls with a few many new precautions and measures in place to adapt to the New Normal. Among these precautions are:

  1. COVID-19 Screening
Belalang worker getting screened by health workers

As required by the authorities, all construction-related non-Malaysian workers are required to undergo testing.

  1. Restriction of movements
    As practiced during the MCO, workers are only allowed to exit their accommodation for essential travel (grocery shopping, medical emergencies and to travel to work). No visitors from other dormitories/accommodations are allowed.
  1. Sanitizer and Mask
    Sanitizers and masks are provided by us to all our staff and workers to protect them as well as our clients.
  1. Briefings and Reminders
    Workers are reminded via weekly briefings and constant reminders to wash their hands frequently, maintain physical distancing when out, and report to us if they have any COVID-19 symptoms.
  1. Provide Transportation
    Instead of asking workers to rely on public transportation or carpool with others, we have ensured that our workers are provided their own transport to and back from job sites.

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Although team Belalang has started operations, we do not take the risks of infection lightly. We’ll strive to keep your green roof and green walls in tip-top shape while taking the necessary steps to keep everyone involved safe.

Here’s a belated Selamat Hari Raya, Selamat Menyambut Pesta Kaamatan and Happy Gawai to our friends and partners. Stay safe and healthy all!

GaiaMat Green Roof bloom in PJ, taken during maintenance in May 2020.

JARO Green Roof, Johor Bahru

Amid the global pandemic, it’s easy for us to put plans on the backburner while personal and business projects are being put on hold temporarily. The uncertainty is proving to be a testing period for many, including us at Belalang. Some say that in every crisis, there is an opportunity; and the temporary slow-down is a prime opportunity for us to reflect and improve.

We’d like to revisit December 2019, when team Belalang implemented an extensive green roof with the GaiaMat green roof system onto an existing metal deck for JARO. Working with Think City, the idea was to green up the roofs to provide cooler temperatures and create a conducive environment for the staff (especially when they look out the window to see lush greenery instead of cold hard metal). Working with the renovation engineer, it was important to check if the roof will be able to cater for the extra load. Fortunately for us, the fact that the system is so lightweight allowed for us to obtain the consultant’s approval to proceed with installation.

Before installation
View from inside the office before green roof installation

Within 2 days, we managed to install the necessary layers, as well as irrigation pump and driplines for the plants. Thanks to the cooperation from the building management, there were no hiccups in temporary storage of materials – creation of handicrafts carried on as usual while we were busy greening up their roofs.

FYI, JARO is an organization that provides training and a workplace for OKU’s around Johor Bahru area specializing in custom-made handicrafts and binding services. It is a rehabilitation center and workshop for the physically, intellectually and visually challenged. For more info, and to support this charity, do visit their website where you can find out more and purchase some local of their handicrafts. JARO website: jaro.org.my

Progress during installation
Driplines are in place, connected to a timer and pump system

Below are some photos taken in February 2020, and in May 2020. Driplines are covered as the GaiaMat ecosystem is established.

Updated pictures taken during CMCO. May 2020
View from the office in May 2020.

The best thing about extensive green roofs and the GaiaMat system is that it is very low maintenace. No need for cutting/trimming and no need for fertilizers. As seen in the pictures above, team Belalang is ready to green up your roofs, be it concrete, metal deck or even GLASS roofs- just send us an enquiry via the “Enquire Now” link above or send us an email at info@belalang.com.my for your own green roof proposal.

Stay safe and stay healthy everyone!

PJ Seapark Residential Green Roof

Last month, Belalangs greened up a rooftop in Seapark, PJ. Apart from the lovely interior and landscape design, we were impressed with the client’s use of space in the home. Glad to have been able to put our Gaiamat in this part of Old Petaling Jaya.