READER RESPONSE (DRAFT 2)

The article “The Concrete Advantage” taken from the Green Rooftop website provides readers the advantages and disadvantages of concrete green roof. According to the article, the process of design, construction and maintenance will be shortened in projects using waterproof concrete as membranes are not required for the development . This in turn leads to higher work efficiency and  reduces the overall cost of the project. On the other hand, the main downfall would be  additional construction cost.

The article mentions that the waterproof concrete contains permanent ""built in"" waterproofing elements that cannot be damaged or torn during service.  This will lead to progressed construction schedule by several weeks and improve project feasibility. Cracks can also be repaired quickly with a simple inoculation from the bottom side of the green roof deck, which does not disrupt growing medium or plants. With lesser exposure risk for owners and designers, such green roofs are more economical which boost return on investment and project value. In addition, this hydrophobic technology removes dangerous element for the designer and owner of a green roof, increases financial viability, and enhances owner acceptance. In all, this project has higher sustainability and a lower life-cycle cost. While this may be true, the lack of analysis on the downfall of the product makes the article less reliable and incomplete.

The first reason is because the article only discusses the benefits of waterproof concrete. It does not state the limitations of the product. In addition, although this hydrophobic system may produce many positive results, it may still not be able to outperform under certain circumstances. For example, this product are not applicable to areas subjected to bending movement and vibrations as the materials used are not flexible (Cementitious Waterproofing (1996). Research studies have also discovered that concrete produced with hydrophobic chemical admixtures could theoretically resist some hydrostatic pressure. However, as not all pores are uniformly coated with the waterproof material, such concrete are not classified as permeability-reducing admixture exposed to hydrostatic conditions (Hooker, 2012).

This article is also incomplete as it did not mention the details on the different types of concrete waterproof admixtures. The benefits highlighted in this article could mainly be referring to a particular waterproof system. Research studies have shown that integral concrete hydrophobic systems generally consist of three kinds of admixtures, namely: densifiers, water repellents and crystalline (Yuers, 2011). Although these three waterproof materials might have the same functions, they each have their own limitations. By comparing all three, the article would leave the readers a better understanding of their characteristics respectively. 

Furthermore, the article did not provide any case studies of successful projects involving the use of integral waterproof concrete. Hence, there is no strong evidence to show the effectiveness of the product. Online research has shown that Waterproofing admix was used in the renovation and expansion of the Mark Jefferson Science Complex at Eastern Michigan University in Ypsilanti (Ken, 2012). Concrete containing crystalline admixture was used to build the green roof slab on the building as well as for a tunnel. Since then, there have been no leaks once the initial cracks were sealed by the admixture.

In conclusion, while this article provides the main advantages of waterproof concrete, it lacks of an analysis of the limitations and description of the system. It is important to know a product in detail so as to evaluate its efficiency and to allow for improvements. Generally, this system has more benefits than disadvantages hence, it is widely used worldwide.

References:

Cementitious Waterproofing.(1996). Retrieved September 25, 2016, from http://www.csibaltimore.org/index_files/Cementitious%20Waterproofing%20-%20Mar%201996.pdf

Hooker. (2012).Waterproofing admixtures for concrete. Retrieved September 25, 2016, from http://www.concreteconstruction.net/how-to/materials/waterproofing-admixtures-for-concrete_o

The Concrete Advantages. Retrieved September 20, 2016, from http://www.greenrooftops.org/advantage.html

Yuers. (2011).Understanding The Pros & Cons of Crystalline Waterproofing Retrieved September 22, 2016, from http://www.kryton.com/in-the-news/2011/04/05/understanding-the-pros-cons-of-crystalline-waterproofing/