How to prevent green wall failure

How to prevent green wall failure
Green wall systems have been around in Singapore for close to 15 years. In early 2000, the idea of having plants as part of the building façade took Singapore by storm. Practitioners of the built industry embraced the novel idea. Studies in many parts of the world also showed the potential of urban greenery to reduce cooling load and improve the environment.

Gradually, green wall fittings became increasingly adventurous. Architects and developers started to specify larger green walls. A-list green wall experts were invited to flaunt their talent here in Singapore (Figure 1). Some of the impressive feats of greening our tiny island has achieved include:

  1. A 100 m high green wall @ Newton Suites by WOHA (Figure 2)
  2. 9 storey indoor vertical greenery @ 158 Cecil Street by AgFacadesign (Figure 3)
  3. Largest vertical garden in the world @ Ocean Financial Centre by Tierra Design (Figure 5)
  4. World’s largest vertical greenery installation in a single development @ ITE Headquarters and ITE college Central @ Ang Mo Kio by RSP Architects Planners and Engineers (Figure 4)
Personally, it’s not that impressive lah. All these can be purchased. You get the green if you got the green. And Singapore has a lot of that. Not the people, just the country.
What is driving the green wall hype? Well for starters, it is heavily subsidised. The Skyrise Greenery Incentive Scheme provides up to 50% of installation costs of green roofs and vertical greenery. This is the big fat worm at the end of the hook. Practitioners in the landscape industry will agree that clients become more receptive once they hear of this initiative. The falling cost of green wall systems is also one reason that has contributed to their rising popularity. A decade ago, the cost per sqm of green walls may be up to SGD 1200. That’s more expensive than Italian Carrara marble! These days, prices can go as low as SGD 300 per sqm. You must be a carrothead if you are still forking out SGD 800 per sqm for your greens.
Costing does not stop at procurement and installation. Maintenance costs, if left unchecked, may result in an inflated building operational budget.
Maintenance is a tricky issue, as overall maintenance requirements are influenced by many independent processes, and most issues will take time to surface. Currently, the responsibility of providing a comprehensive placement, installation and maintenance package is not assumed by a single person but shared among several groups of people.
This is evident when we consider the entire process of green wall installation and operation. Who is supposed to ensure the longevity of the green wall system?
  • Not the client, cos he is paying for everything, and he sure as hell paid for someone to handle such issues.
  • Not the architect, cos his job is to allocate space for the green wall(s) and make sure it is not in conflict with other building services and regulations.
  • Not the green wall contractor, cos he has been assigned his area to install his green wall system and everything else is not under his purview.
The only group feeling the pinch are building facilities managers, who have to ensure functionality of the green walls even though they were not involved in the design / installation of the green wall. Look at Figures 1 to 5 again, and try to imagine them all with failed green wall systems. Figure 6 shows that near complete failure is a possibility. 
That's my green wall

Though it is not the fault of the building facilities manager, he will still have to clean up the mess. And because this means extra work and raises the operational budget, the building facilities manager will have less inclined to recommend having green walls for future projects.
This vicious cycle that will end up diminishing the confidence clients have in green walls. The many benefits that greenery can bring to the urban environment will not be realised because of oversight. Fortunately, this is a problem with a simple solution, in the form of a comprehensive green wall design and maintenance checklist for vertical greenery systems, and a 3rd party who will oversee the entire process of green wall design to maintenance. The aim is to ensure:

  1. Clients will have realistic expectations to the impact of adding greenery to their building;
  2. Architects can complement their aesthetic intentions with a robust maintenance strategy; and
  3. Contractors will consider aspects of plant selection, lighting and irrigation to minimise failure.
The complete workflow is part of the UGL WLMJ, and is exclusive to our consultancy.
Next time you meet your landscape guy, try poking him with a few questions:

  1. What is the maintenance plan for your proposal?
  2. Is lighting an issue for this part? (Point to any corner of the green wall)
  3. Don’t you think that your green wall modules are too heavy to be replaced if needed?
  4. Can you name 2 alternatives to the plants you proposed?
Lastly, if they even hint that their system is maintenance free, that’s the cue to drop them.
In my next article, I will elaborate on why any system cannot be 100% free from maintenance. Stay tuned.
– Z

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