Precast concrete products protect home and building occupants.
By Dean A. Frank, P.E.
Hurricanes. Fires. Tornados. Floods. Bombings. All of these events are constantly bombarding us on television, in newspapers and online. Everywhere you look, a story recounts the world’s latest catastrophe. Consequently, many people feel that there is a loss of control in their lives, leading to a sense of reduced security and safety. A typical human response is to retreat into the home. People not only need to be safe, but they also need to feel safe – especially inside their homes. Fortunately, concrete addresses both of these issues, because concrete construction is one of the safest of building materials.
Concrete products are the best construction material to resist damage and destruction caused by catastrophic events. This became clear when damage assessment teams made their way through the ruins of the 2005 Gulf Coast hurricanes and flooding and found that homes constructed with concrete products remained standing and suffered comparatively minor damage. Precast concrete can stand up to the elements – both nature’s and human.
Hurricanes and tornados get a lot of attention – and for good reason. The impact of such events has a tremendous effect on the economy and the public psyche. In years past, the typical reaction by building code officials to catastrophic wind events has been to raise the basic wind speed used to design buildings. However, the problem is not wind speed, but rather windborne debris from substandard construction. Fortunately, concrete products are not only good at protecting building occupants from flying debris, but also are heavy enough to prevent them from becoming missiles themselves.
When hurricanes strike significant damage is often caused by water. Storm surges and massive amounts of rain cause widespread flooding, which can quickly destroy homes and buildings. Wind-driven rain also can be problematic for buildings and their occupants. The normal water-shedding capabilities of exterior walls can be overcome by water that is forced into and around building materials, leaking to interior flooding and problems with mold later on. Timber frame homes are havens for mold growth. Wood offers mold the vital food source for growth, but concrete lacks that food source and is resistant to mold growth.
Not only are concrete products strong, they provide the best fire resistance of any building material. Concrete is noncombustible – meaning that it neither burns nor supports combustion. Unfortunately, timber frame construction is highly susceptible to fire damage. Furthermore, concrete maintains structural integrity much longer than other materials used to construct homes and other buildings. It does not emit toxic gases or smoke, and does not melt or drip molten particles when exposed to fire.
Because concrete and its constituent materials offer poor thermal conductivity, the rate of heat transfer through it is relatively slow. As such, it protects the reinforcing steel embedded inside and also acts as a barrier to the fire, keeping it from spreading to adjacent rooms.
Concrete can also provide protection from the explosive force of bombs by either shielding the occupants from the blast or absorbing the blast force with sacrificial exterior surfaces.
Precast concrete can be made in any shape or form and with a very high degree of detail. For example, precast concrete can be made into radius shapes, a process virtually impossible to do with other building materials. Trim and components such as lintels, window sills, banding and door surrounds can all be cast into one piece. Precast concrete can also be used for the foundations, floors and even roofs of homes. Its design flexibility allows homeowners to reduce overall costs through repetition of products and speed of construction. A typical home can be erected and enclosed in a day or two.
Precast concrete has a distinct advantage over other building materials. It can be made to resemble diverse finishes like brick, stone, wood, smooth concrete, various textures and patterns, exposed aggregate and combination finishes. The possibilities are limited only by the imagination.
Construction using precast concrete can be completed much more quickly than conventional timber frame or cast-in-place concrete construction. Precast concrete products are manufactured off site in a quality controlled environment and delivered to the job site ready to install.
As a direct result of precast concrete’s high resistance to water, moisture, mold and insects, it is also a material that requires little maintenance. Wear and tear over time has negligible effect on concrete.
With so many advantages, concrete products are increasingly taking up residence in homes and buildings because of their inherent quality, value and permanence.