Article No: 171

2006-05-03 10:07:47
Tech Talk
By: Jim Baty


 

Part I: This article begins a six-part series to develop a better understanding of the detailed solutions that are offered in the above-grade concrete home industry delivered by removable concrete forms (RCFs). Since strongly entering the market nearly a decade ago, this method of construction offers an ever-expanding variety of architectural and practical construction solutions for today's homeowner and designer.

So, you want to build and own a concrete home. A great decision, for sure, as the market has proved over and over the durability, security and efficiency of concrete for homeowners. Couple that with the often understated beauty and sophistication of concrete homes and you have the recipe for a truly out-of-the-ordinary home that can be as ordinary in appearance as the house next to you or a unique statement of your own personality. However, simply making the decision to own a concrete home isn't the end of the process.

There are many design options to consider and forms this development can take. Will your home be constructed with exterior walls of concrete only or will it have interior walls that are also concrete? Will your home have a secure ceiling deck of concrete to protect you from the forces of nature that continue to ravish our regions? Will it seek the advantage and feel of concrete in other areas such as stairs and counters or floors and roofs? These are all questions that can be asked, and questions that can be easily answered, by the construction team that will deliver the final product. There are many more details that make these houses fashionable homes as well, but truly the decisions start by selecting the right system.

Concrete walls
The structural concrete wall is the first and primary noticeable difference between the construction of above-grade concrete homes and the more traditional method of wood framing. Drive down the streets of developments today and you will see row after row of homes in varying stages. You can see completely through the framework for weeks on end. The natural elements are already diminishing the quality of the home and the builder must work to "seal" these forces out for the comfort of the final product. To see a difference, drive down a street where a concrete home is underway. From the time the forms are placed, the home can no longer be viewed from the outside. Once the concrete is delivered, a monolithic, energy-efficient barrier is transformed from the most durable and flexible construction medium available to builders and owners today. The exterior of the home is the primary barrier to the natural and physical environments. It affects not only durability, but also security. What is often underestimated or not considered, however, is that the finished concrete can and does provide warmth and solitude, separating the interior space from the exterior environment.

For that reason, interior walls are also a key decision to consider for concrete. There are many reasons why a homeowner should look to separate a kitchen from a living room or from bedroom suites with concrete or separate bathrooms both semi-private and private from adjacent living and sleeping spaces. Unmistakably, concrete provides the highest level of fire protection and containment in construction, which may give valuable minutes to occupants. It also provides unparalleled sound control with the ability to turn the entire home into a haven of linked and separated spaces. We will talk about manipulating these walls to accommodate the myriad of needs homeowners have--but let's not get bogged down by those concerns at this point. What is important is that you select wall constructions that can deliver the quality of the space first and foremost.

Concrete decks
As with the walls, whether you are looking at a floor system or a ceiling system, concrete can be a primary opportunity when considering the desired performance of the overall space. Perhaps one of the most annoying aspects of past and current homes are floors that squeak, bounce or sag. Turning to concrete, a monolithic and reinforced slab eliminates all of these issues while adding a wider variety of finish opportunities and service potentials. Combined with exterior concrete walls, a concrete ceiling deck develops a monolithic shell providing the most secure structure available for complete protection of the home, its contents and the family living there. Designed for both impact and severe wind loads, structural fatigue can be prevented, contributing to sustainability of the designed quality.

Once the wall decision is made, completing the structural envelope by adding decks is a mere modification of the forming system to provide total protection. We will discuss some of the finer details of integrating deck systems with walls later in this series as we begin to understand more than just the security and durability of this added feature.

A hat for your house
As with the decision to wear a ball cap, a fedora or a hard hat, the decision for the roof to complete both the architectural and service design of your home can play a key roll in the selection of the overall construction system. The walls are concrete and the decks are concrete, but does the roof have to be a complicated sloping concrete roof as well? Certainly a decision merits consideration, but the answer is as flexible as the selection of these other components. Many homes are delivered secure in the maintenance of the interior spaces with concrete decks and therefore choose a traditional roof construction to complete the design. This allows for the myriad of complex framed roof concepts that place an exclamation point on today's homes. When faced with the forces of disaster that are protected from the interior by the concrete walls and decks, the roof, however, can often be considered a dispensable element. In other words, the roof can be removed by wind forces without damaging the contents and the safety of the home, protected by the concrete ceiling deck. Although this still results in insurance claims, it is one way to plan for trade-offs in the cost of construction versus impact to durability.

Still others may choose to complete the decision for concrete walls with a concrete shell through the roof. In these designs, the decision to employ a concrete ceiling deck may be excluded since the structure is continued well above it. Forming these roofs can also influence the complexity of the design. Many of these structural concrete roofs are seen in the entry level or mass housing markets. Still, as technology continues to play a large role in the success of above-grade housing, this too will see continued growth into traditionally higher markets.

Final thoughts
The residential market has been experiencing an exciting transition spurred by concerns for efficiency, durability and safety. The response to this transition developed in the RCF systems continues to open doors in markets from Michigan and Oklahoma, to Florida and points in between. As we talk about the details that make these systems work, we will see many of the reasons for resisting this trend turn to urges to get involved in the progress or take ownership of the state of the art in housing.

For more information about CFA, visit cfawalls.org or call (319) 895-6940. For more information about CHC, see concretehomescouncil.org or call (319) 895-0761.

Jim Baty is Technical Director of the Concrete Foundations Association and may be reached at (319) 895-6940 or noSpam("jbaty", "cfawalls.org"); jbaty@cfawalls.orgjbaty at cfawalls.org.