Concrete Offers Strength, Beauty and Efficiency
Many owners of companies involved in light commercial building and commercial remodeling started out by diversifying from single- or two-family home construction. As a result, they are often most familiar with one aspect of concrete — its use in foundations and basements.
But there’s actually far more to this area of construction than some commercial builders realize — including a great deal of new technologies and materials. Even though concrete is the most widely used construction material on earth (and has been used to build structures that still stand after more than 2,000 years), the industry continues to evolve to meet the demands of builders.
At the same time, as I’ve learned through my service on NAHB's Concrete Home Building Council, many builders face a full-time job just keeping up with current projects and have little or no time to learn about new technologies and building systems. That’s where I, and my fellow council members, hope to help.
A New World of Possiblities
In response to industry demand, concrete and cement manufacturers have developed new materials, processes and systems to reduce the cost of doing business, speed up construction and increase profits.
What’s more, concrete technology can be essential for architects and builders seeking green building certifications for their projects, as well as a variety of antiterrorism, force protection and security applications.
Moving from smaller commercial construction to larger projects can require knowledge about a range of issues regarding concrete construction.
To name only a few examples, one may need to learn about new types of drawings, calculations, engineering specifications and permitting processes. There are also new work site processes to incorporate, including preplanning, forming techniques, staging areas and shoring systems required for multiple levels under construction at the same time.
The Portland Cement Association (PCA) has taken a proactive approach to serving NAHB members by participating on both the Commercial Builders Council and sponsoring the Concrete Home Building Council.
My role in these two groups is to serve as a resource for members seeking expertise on concrete technologies and systems, and to point the way to resources available at my organization and elsewhere.
Concrete Is Everywhere, and It Is Versatile, Too
In every big city, there are a few very tall, highly recognizable buildings — nearly all the rest are significantly smaller. In fact, less than 1% of all buildings exceed 15 stories and the vast majority of all commercial construction is in one-, two- and three-story buildings.
Unlike the concrete foundations poured for the typical home, nearly all of these structures feature engineered solutions involving concrete.
Even if you’ve never worked with engineered concrete, you’re probably familiar with the “old school” approach of using rebar to reinforce a slab of concrete. Today’s choices in engineered concrete offer a different and wider array of capabilities and benefits that require additional areas of expertise.
One of the remarkable things about concrete is its versatility — not only in the forms it can create (which include virtually any form that an architect can devise), but also in the benefits it provides to the project and the quality of the structure.
For example, concrete’s thermal mass slows a structure’s temperature swings and often lowers the peak energy load. This, in turn, can reduce the building’s energy usage as well as the size of the HVAC equipment required.
At the same time, concrete can provide aesthetic and security benefits.
Case in Point: The Power of ICF
To appreciate the potential of new concrete technology, consider insulating concrete form construction, or ICF.
This established and approved technology delivers huge benefits — including superior acoustics and resistance to mold and mildew, vibration and even hurricanes and earthquakes. This builder-friendly wall system has found its way into new construction projects in every region and price range.
Two basic types of forming systems are available. One uses hollow, interlocking polystyrene blocks, while the other uses panels or planks held apart by a series of plastic ties. After using the forms to construct a hollow wall with vertical and horizontal reinforcements, contractors pump concrete into the cavity to create a solid structural wall with insulation on both sides. Later, electricians and plumbers cut channels into the insulation for cables, wiring and water lines.
The process results in super-efficient insulated walls — from R-20 to R-56 — in a fraction of the time required with wood or steel framing.
What’s more, the insulation provided by the forms gives builders the ability to successfully place concrete even under extreme weather conditions. Very few weather conditions affect a pour because the form insulates the concrete — allowing it to cure almost regardless of ambient temperature or humidity.
What’s New in Concrete?
The cement and concrete industries offer a broad range of materials and systems. The following are a few of the newest and most popular applications.
- Shotcrete (a.k.a. “gunite” or “sprayed concrete”) — Concrete sprayed onto surfaces at high velocity. Ideal for curved or thin concrete structures and shallow repairs, shotcrete can be used to create swimming pools, grain silos, fire-proofing structural steel and many civil engineering structures such as bridges, tunnels, dams, tanks and earth retention systems.
- Tilt-up Concrete Construction — A method in which walls are cast in a horizontal position and then tilted into a vertical position and moved into place with a mobile crane. Frequently used for warehouses and office buildings of one to four stories, tilt-up concrete has also been used for condominiums and hotels as tall as 10 stories.
- Green Roofs — As the structural system of choice for vegetated roofs, concrete provides a continuous load-bearing absorptive surface for the potentially moist growing medium and plants. Lightweight concrete can be used to reduce deadload and create sloping decks for vegetated roofing.
Build Your Success on Concrete
Successfully incorporating appropriate concrete materials and systems into projects results in a win-win situation for builders, owners and tenants. Whether it’s a 50-story building, a smaller office building or a custom home, concrete delivers a high quality product, with wide flexibility in features and benefits.
As with any building process, the key is knowing the right approach to use for your particular end results and understanding which types of professionals and subcontractors you need to accomplish your vision.
Where to Learn More
For builders of every size and market focus, NAHB offers a range of courses and seminars that touch on various aspects of concrete construction. In addition, NAHB has incorporated material from PCA and other expert sources in a variety of brochures and literature that address specific areas of concrete construction.
For more immediate insights, visit the online resource PCA developed at www.concretethinker.com. This is a one-stop resource that helps design and construction professionals make sustainable design a reality using the durability, versatility and energy performance of concrete.
Members can also tap the resources and members of the Commercial Builders Council and the Concrete Home Building Council for more information.
Ed Alsamsam, PhD, PE, SE, LEED AP, is the general manager of buildings and special structures for the Portland Cement Association based in Skokie, Ill. His team develops publications, designs software, conducts seminars, provides technical support, performs feasibility studies and manages research and development projects. Alsamsam is an active member of NAHB, the American Concrete Institute, the American Society of Civil Engineers and the Structural Engineers Association of Illinois, and serves on various technical committees. He has authored, published and presented numerous papers and reports in the field of structural engineering. For more information, e-mail Alsamsam at PCA, or call him at 847-972-9080.