The New American Home 2008 was constructed with a relatively new concrete system and some of the most trusted concrete technology.  All the exterior structural walls were built with time-proven cast-in-place concrete and concrete masonry blocks and autoclave aerated concrete blocks, one of the newest concrete building systems used in the United States.

Other types of concrete home building systems include precast concrete forms and insulated concrete forms (ICFs). Each system provides its own unique design options while maintaining the many advantages of concrete construction.

Moreover, on all concrete homes, interior and exterior walls can be completed to meet the homeowner’s preference. The concrete itself can be finished to look like brick or other finish styles, or just as in traditional construction, homeowners can add vinyl or fiber-cement siding, stucco, brick, or stone to achieve the exterior appearance they desire.

Autoclaved Aerated Concrete
Although, autoclaved aerated concrete (AAC) systems consist of blocks held together by mortar like concrete masonry, the two systems are very different. AAC uses new, technologically advanced concrete and mortar to give builders and buyers a new range of advantages. AAC is made with all fine aggregates, nothing more coarse than a grain of sand, cement and a natural expansion agent that causes the concrete to rise like bread dough, with countless small air pockets. In fact, this concrete is 80% air.

ACC can be molded and cut it into precisely dimensioned units. While block-size is most common, it can also be cast into reinforced panels for walls, floors and roofs.

The Autoclaved Aerated Concrete Products Association champions the industry by creating and maintaining a dynamic network bringing together resources, knowledge, and innovation. For more information on this building system visit www.aacpa.org.

Removable Concrete Forms
Traditional concrete forming, also known as cast-in-place, is typically associated with basement foundations and commercial construction. However, in recent years a number of form manufacturers have utilized their products for the above ground walls and floors of single-family homes.

With conventional cast-in-place construction, a crew erects forms of plywood, steel, or aluminum that make a mold in the shape of the desired walls. After placing steel bars to reinforce the wall, the crew pours concrete inside the cavity. Once the concrete hardens, the crew strips the forms, leaving the reinforced concrete walls. For above ground walls, a layer of rigid foam insulation is attached on both or either side of the concrete, or within the inner cavity, to provide additional energy efficiency.

Some cast-in-place systems make it possible to use form liners or apply architectural finishes to the exterior surface of the concrete. On the interior, a thin layer of plaster is typically applied, with painting as the final step – it is not necessary to install drywall.

The Concrete Homes Council, an alliance organization of the Concrete Foundations Association and several other organizations including PCA, maintains a Web site at www.concretehomescouncil.org. This group is committed to advancing the use of removable concrete forms for above-grade residential applications.

Concrete Masonry
Common in school and other public construction for years, concrete masonry is also a viable option for homes. Using this time-proven technique, masons lay a series of courses, or rows of concrete block. Each course is set on a layer of mortar to bind the blocks and to ensure proper spacing. For added strength, the block walls are often reinforced with concrete that is pumped into the blocks. Builders can add insulation to the inside of the block, on the exterior walls or interior walls. New blocks are up to 25 percent lighter in weight than traditional blocks resulting in quicker installation than was possible in the past. Stucco is often applied to the exterior walls to complete a beautiful, secure home.

The National Concrete Masonry Association works to further the cause of masonry construction in North America. Visit www.ncma.org to learn more. The Portland Cement Association’s residential Web site, www.cement.org/homes also has useful information about concrete masonry.

Precast Concrete Forms
With precast technology large sections, or panels, of concrete walls are poured horizontally in a carefully controlled factory environment. Openings for walls, doors, electrical and plumbing lines are selected in advance of the pour. The factory setting ensures a very high level of quality, which is unaffected by weather or unexpected job site conditions. Once completed and cured, the panels are delivered by truck to the job site, lifted into place with a crane, and fastened together. Precast panel systems often incorporate a layer of foam insulation to greatly enhance the energy efficiency of the completed wall.

A textured orange peel finish and coat of latex paint are all that is needed to finish the interior panel. The combination of concrete and foam insulation delivers an aesthetically pleasing home with superior energy efficiency, durability and moisture resistance. A precast home can utilize virtually any blueprint design.
The Precast/Prestressed Concrete Institute maintains a Web site at www.pci.org.

Insulating Concrete Forms
One of the fastest growing methods of home construction in the United States involves the use of insulating concrete forms (ICFs). Two basic types of ICF systems are currently available. One uses hollow, polystyrene blocks that stack and interlock almost like children’s building blocks. The other uses panels or planks that are held a constant distance apart by a series of plastic or metal ties.

After using the forms to construct a hollow wall with vertical and horizontal steel reinforcement, contractors pump concrete into the cavity to create a solid structural wall with insulation on both sides. Unlike traditional concrete forms, the forms stay in place and the polystyrene insulation on either side of the concrete functions as the insulation for the home. Drywall is screwed into the fastening surface on the interior side of the forms. The result is a highly energy-efficient, disaster-resistant home that fits into any neighborhood.

The Insulating Concrete Form Association (ICFA), Portland Cement Association, and other allied organizations have produced a variety of technical, training and promotional tools concerning ICF construction over the last several years. For more information about ICFs, visit www.forms.org, www.cement.org/homes or www.icfweb.com.

About the Portland Cement Association
Based in Skokie, Ill., the Portland Cement Association represents cement companies in the United States and Canada. It conducts market development, engineering, research, education, and public affairs programs.