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Life-cycle approach to material selection

Every day people around the world make important economic decisions that allow them to continue their daily lives. When it comes to these daily decisions something that many people do not know is that in some cases, cheap things mean higher costs. The quote, “I am not rich enough to afford cheap things,” is a clear representation of this notion. This quote portrays that people who are not rich cannot afford to buy cheap things, as they are more expensive over time. This is because cheap items tend to need to be replaced or repaired more frequently over time, resulting in higher costs. Unfortunately, many people still fail to see the ultimate expense of cheap things.

The same logic can also be applied to buildings. When building a structure, there are two approaches one can take. One commonly chosen option is to follow the conventional design model. A conventional design takes note of the upfront costs and tries to decrease them in order to make the cost fit within the budget allocated for the project. Most of the time, this means that lower quality materials are used to reduce costs. These cuts in the quality of materials can include anything from the quality of the paint, to even indispensable aspects of the structure itself such as the waterproofing system. Though using lower quality materials initially will help cut costs, in the long run, they will make the structure more expensive to maintain. Lower quality materials are less durable and as a result have shorter life span. This shorter service life results in the need for frequent repairs or replacements which will surely exceed the cost of using high quality materials in the first place.

For example, someone has two roofing options, option A which is $20,000 and option B which is $30,000. While option A will only last for approximately 20 years, option B will last for about 40 years. By paying an extra $10,000, 20 years of extra service life are bought. Furthermore, the cost per year for option A accounts to $1,000/year, whereas the cost per year of option B only accounts for about $750/year. Thus, although option A may seem more appealing upfront, the more economical choice is actually option B when considering the service life of the structure.

Due to the drawbacks of a conventional design, a new design model called a “sustainable design” has been developed. This kind of design not only reduces environmental impacts, but it also reduces costs over the structure’s lifespan. The primary economic goal for a sustainable design is to reduce life-cycle costs (LCC) through two distinct methods. LCC is defined as the sum of all recurring and one-time costs over the full life span or a specified period of an item, service, structure, or system. As shown before, the lifetime costs for high quality and more durable materials are lower, and they also possess another distinct characteristic. Materials that can be later reused or recycled have the potential to be resold in order to gain some of the money that went into their initial costs back. These materials are said to be taken from cradle-to-cradle. On the other hand, materials that cannot be recycled or salvaged do not have this benefit. Instead, they are termed as going from cradle to grave.

The construction industry has been undergoing a transition towards the development of more sustainable and green built structures because of the appealing characteristics of sustainable design. One of the products currently gaining the attention of customers because of its ability to conform to sustainable design principles is integral crystalline technology. This innovative waterproofing solution is added directly into the concrete mix making it permanently watertight. When added to concrete, the crystalline technology chemically reacts with water and components in the concrete mix to form insoluble crystals that fill capillary pores and micro-cracks in the concrete and block the pathways for water and waterborne contaminants. Integrally waterproofed concrete becomes watertight for the life of the structure avoiding costly leaks. This technology can potentially save builders money in reduced labour and maintenance costs, resulting in a durable and resilient structure for the long-term.

As construction trends continue to evolve, the importance of a robust consideration of life-cycle costs is increasing. Using a sustainable design that incorporates high quality materials, we can not only save money, but we can also reduce environmental impacts of construction. In short, we are hitting two birds with one stone.

Alireza Biparva currently holds the position of R&D manager /concrete specialist with Kryton International Inc. in Canada. His areas of responsibility include project planning and management, leading a staff of engineers and technicians, and liaising on a global level with universities, testing facilities, and engineering firms. 

Source: Construction Business