Reader's Response (revised)

In the webpage “The Concrete advantage” from the Green Rooftops’ website, the National Ready Mixed Concrete Association (NRMCA) explained why a concrete green rooftop is simple, inexpensive and durable compared to a membrane system. The concrete roofs are more feasible, which ensures better investment for the “society and owners”. It is also waterproof by nature, which eliminates the need for waterproofing sub-contractors. Both designing and detailing work are not needed too. This allows for a quicker construction and lower building cost. On top of that, it is highly probable that a root barrier is not required as well. The author also stated that the concrete green roofs do not deteriorate over time and they are easy to maintain. Unlike the membrane system, cracks are easily detected through leakages and fixing them only requires an injection.

While the article identifies the advantages of using a concrete green rooftop, it fails to state the drawbacks of a green rooftop.

First, there are requirements that a building structure must fulfil to support a green roof. One of the factors is the thickness of the roofs. For the plants’ roots to grow properly, the roofs must be 6-18inches thicker than a conventional roof. The added thickness will increase the weight of the roof and the load bearing walls of some buildings may be unable to prop up the added weight. Moreover, the roofs can only be constructed on a flat surface. “It should have no more than a 20-degree slope, if not lower, ideally as flat as possible” (Glazer, 2015). This makes green roofs incompatible with some buildings.

The second drawback of a green roof is its cost. NRMCA (2011) asserts that green roofs are “financially viable, with less exposure risk for the owner and designer, which increases return on investment and project value”. The author further illustrates how a green roof reduces the temperature within the building as it reflects the sun’s heat rather than absorbing it. However, a white painted roof which is also known as a ‘cool’ roof, could produce similar results. “Green roofs might cost $25 to $30 a square foot; a cool roof would cost a fraction of that” (Strickland, 2009). The price of a green roof is almost twice the price of a conventional roof.

Finally, a green roof requires much more maintenance than what the main webpage claims. A green roof is practically known as a garden on the roof and gardens require regular upkeep (e.g. trimming, weeding). Furthermore, frequent inspections must be conducted to ensure that no leaks are present and to ascertain that the green roof is structurally sound. In most cases, finding a leakage can be a complex task. It requires an electronic device that sends out electrical charges to trace the path of the leakage. If any leakages are found, repair works can be rather exorbitant. These instances of maintenance works required for a green roof underscore the effort and recurrent costs involved.

In conclusion, I do not think that having a green roof is a viable investment and the biggest advantage of having one is its aesthetic value. However, in preserving its allure, there are numerous unforeseeable circumstances and additional costs involved. The advantages of a green roof do not justify its price.

References

Salter, A. (2018, September 18). Disadvantages of Green Roofs.

Retrieved from https://www.hunker.com/12003790/disadvantages-of-green-roofs

Galbraith, K. (2009, May 19). Green Roofs: Are They Worth the Expense? Retrieved from https://green.blogs.nytimes.com/2009/05/19/green-roofs-are-they-worth-the-expense/

Downton, P. (2013, July 29). Green roofs and walls.

Retrieved from http://www.yourhome.gov.au/materials/green-roofs-and-walls

Taylor, M. (2015, May 22). What a Green Roof Costs You on the Way to Saving Everything.

Retrieved from https://www.thestreet.com/story/13161050/1/what-a-green-roof-costs-you-on-the-way-to-saving-everything.html