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Life Cycle Cost Design

Conventional Design vs Sustainable Design
By Alireza Biparva

Concrete, concrete, concrete, it really does make the world go round. Or, at least, allows us to go around the world as it makes up our roads, bridges, highways, tunnels, airport landing strips, and much of our infrastructure. Concrete also allows us to build astronomical structures, climbing higher than the eye can see and further underground than ever thought possible. The fact is concrete is all around us.

As of right now, concrete is the most used man-made material in the world. ln fact, twice as much concrete is used around the world than the total of all other building materials combined, including wood, steel, plastic, and aluminum. According to a 2007 United States Geological Survey, (Minerals Commodity Summary — Cement, nearly 3000 kg of concrete is used for every man, woman, and child on the planet every single year. The reason concrete is used so readily is that no other building material can match it in terms ofeffectiveness, price, and performance for most purposes. However, unfortunately, in many cases concrete is not made, placed, and/ or cured as it should be, in which it can lead to premature failures.

As seen throughout the world, concrete structures are deteriorating at an alarming rate and with that the economic pressures associated with maintenance, repair and replacement costs are stressing the financial vulnerability of cities, provinces and countries. Furthermore, when structures don’t achieve an optimal life span, or require regular maintenance and repair, the environment suffers through the depletion of natural resources, pollution from construction process, and adding to our ever increasing landfills.

Aside from mechanical failure, the most deadly force deteriorating concrete before a useful life span is water. In fact, water continues to damage or completely destroy more buildings and structures globally than war or natural disasters. That said, water ingress can be prevented with high quality waterproofing products. However, when initial project costs are cut, a project will suffer in the long term. On many occasions this has to do with the project design choice.

One common option is to go by a conventional design. A conventional design takes note of the upfront cost and tries to decrease it in order to make it correspond with the budget allocated for the project. The majority of the time, this means that lower quality materials or inappropriate systems must be used in order 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 a concrete waterproofing system. Through using lower quality materials initial costs will be cut; however, over the long run, it will be more expensive to maintain. Lower materials are less durable and as a result have a lower life span. A lower life span results in frequent repair or replacement costs.

For example, in the concrete waterproofing industry there are many different products to choose from using different applications and technology. Conventionally, surface applied membranes are used as the waterproofing measure for concrete projects the world over. They are inexpensive to initially buy; however, the lifespan of an externally applied membrane is far-less than that of an internal membrane using crystalline technology. This causes in maintenance repairs to concrete leaks, some of which are extremely tough and costly to get repaired. Further, the damage done to the concrete through the ingress of moisture will cause premature deterioration of a building, causing a replacement cost. The repair, maintenance and replacement costs not only add up financially, but will also harm the environment further. The more natural resources used, pollution released and unrecyclable products trashed, the worse off the planet will be.

Due to the drawbacks of a conventional design, a new method called a sustainable design’ has been developed to not only reduce environmental impacts but also reduce costs over the structure’s life span. The primary economic goal for a sustainable design is to reduce the life cycle costs (LCC) through two distinct methods. LCC is the sum of all recurring and one-time (non-recurring) costs over the full life span or a specified period of a good, service, structure, or system. The LCC includes the purchase price, installation cost, operating costs, maintenance and upgrade costs, and remaining (residual or salvage) value at the end of ownership or its useful life. Traditional building processes look only at design and construction costs, or first costs, and not LCC.

As noted before, the costs of the lifetime 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 then sold in order to gain some of the money back that went into their initial costs. On the other hand, materials that cannot be recycled or salvaged do not possess this benefit.

This is why construction projects globally are moving toward a sustainable design method. Products and materials are not chosen based solely on price, but more about effectiveness in creating a structure that will ensure an appropriate lifespan with minimal associated maintenance costs. Initial costs still become part of the equation; they aren’t just buying the most expensive products and materials, rather choosing the right products.

In conclusion, through 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, B.Sc., M.A.Sc., LEED Associate, is research and development manager/concrete specialist at Kryton International Inc.