Findlay, Ohio, April 20, 2001 -- There are numerous ways to build a residential structure. For centuries, wood was the chosen material, first starting with logs and rough-hewn timber as the framing structure and then moving to the clean-cut 2X4s, 2X6s, and the pre-formed framing pieces of today. But in the 20th Century, engineers started experimenting with new types of building methods including steel framed buildings and concrete homes.

"In some areas of the country, most notably the southwest and southeast, concrete homes have enjoyed immense popularity," says Roy Reiterman, technical director for the Wire Reinforcement Institute. "Concrete offers a great flexible and durable way to construct a home. But the key to building a concrete home is using the correct type of reinforcement. There has been some misleading advertising in the concrete trade, primarily related to slabs, that has alluded to the viability of placing concrete without steel reinforcement. In fact, in some cases, the engineers and architects are specifying steel reinforcement but it is being removed at the construction site. The fact remains that there is no substitution for steel reinforcement and we're now finding out that projects done without steel reinforcement are prematurely failing."

When it comes to steel reinforcement for concrete, rebar has traditionally been the major shareholder in the United States. In fact, in 2000, the total U.S. market for steel reinforcement was close to 10 million tons. But savvy engineers and builders in the United States are using another form of concrete reinforcement. Welded Wire Reinforcement (WWR) is a technology that celebrates its 100th anniversary this year, but despite it's age only makes up about 3% of the structural reinforcement market.

"WWR is more commonly known as fabric or wire mesh," says Reiterman. "It is similar to rebar in that it provides structural reinforcement in concrete. But it is very different. First, WWR is cold-worked, which means it has a higher yield strength. Additionally, WWR comes in preformed sheets which means contractors don't have to waste jobsite time tying together the steel in a pattern like they need to do with rebar. This means the reinforcement is more properly spaced, the concrete placement is quicker, the inspections are made easier, and money is saved in labor."

So with these obvious advantages, why has WWR traditionally taken a backseat to rebar? Part of the problem is misconception and the other is a lack of knowledge about the product. Over the past 100 years, the technology of WWR has changed and the types of WWR offered have evolved.

"The fact is you can use WWR anywhere you use regular rebar," says Dr. Maher Tadros, a professor at the University of Nebraska and principal of Tadros Associates of Omaha. "The common misconception among architects and structural engineers is they think of WWR as the type of mesh that they can purchase at a hardware store: small wires and flimsy handling. While WWR does come in the smaller sizes, it isn't the material that would be used in major concrete structures. In fact, some WWR manufacturers can produce sheets made up of wire that is 1/2" to 5/8" and some to 3/4" in diameter. This directly translates into #6 rebars and larger. So in actuality, WWR can replace rebar in any project that calls for rebar from #3 to #6 and at the same time provide superior reinforcement properties as compared to rebar. Even if a larger than #6 rebar is specified, one can substitute the same sizes or smaller wire sizes and smaller spacing between wires. Small spacing is a great benefit that WWR offers at no extra cost. It is what structural engineers aim for in design but cannot afford to specify for field-tied rebar."

In fact, the ACI 318 Building Code has for a long time recognized welded wire and rebar as equal steel reinforcement. For many years, previous ACI Code cycles have allowed wire, welded wire and rebar yield strengths to 80,000 psi for flexural strength. But since the ACI 318-95 Code approved deformed welded wire to 80,000 psi in shear as well as flexure, there has been increased demand for structural WWR. WWR with 80,000 psi yield strength can be used in place of the more commonly used Grade 60 rebar. This represents a weight savings of around 25% over rebar. Thus, according to the ACI Code, one can reduce the cross-sectional area of WWR proportional to the strength increase.

Professor Tadros is so convinced of WWR's superiority in concrete reinforcement, that he has undertaken a project in Omaha that has him building a concrete home unlike any other using only WWR as reinforcement. Almost the entire home will be made up of WWR reinforced concrete panels from the floors to the walls to even the roof. The project is being developed with the participation of four groups: The University of Nebraska, Enterprise Precast of Omaha, homebuilder TFF Inc of Omaha, and Dr. Tadros himself.

"This project will really show off how WWR can be used in residential home construction. I'm hoping that other builders will be able to use it as an example of how they can improve their building projects," says Professor Tadros. "The house will be a raised ranch style home, built with precast walls. The envelope will be concrete, including the roof and the floor. The basement and foundation will also be concrete. All of the reinforcement will be WWR."

Professor Tadros says he is hoping that this home project will dispel some of the misinformation about WWR and convince engineers and architects of its viability.

"Whenever I'm speaking to someone in my area about the benefits of WWR, I invite them to one of our local precast producers so they can see how WWR is used in bridge girders," says Professor Tadros. "Some of the girders can be two meters or 6 foot-7 inches tall, and WWR appears not only in a grid pattern in the flanges, but also as vertical shear reinforcement at even spacing in the stem. WWR simply offers much more placement accuracy and structural efficiency than rebar. As a significant bonus for the precast concrete producer, labor to fabricate these large girders has been cut by 30 to 40 percent. It's always surprising to see the reactions because despite WWR being over 100 years old, people are shocked to find that WWR can be used for applications other than concrete driveways."

"When constructing a home that has concrete in either the walls, driveways or foundations, the most effective reinforcement is welded wire," says Dr. Tadros. "While my concrete house project may contain more concrete and reinforcement than your average residential home, it does illustrate the flexibility of the WWR product. My advice to those involved in building residential homes is to consider the use of WWR. If you have a wall, especially below grade walls, WWR is a superior product. Any cast-in-place or precast concrete walls can accept WWR. Welded wire reinforcement is one of the best concrete reinforcement products available today to help builders accelerate their projects, save money and build a better quality structure."

"The fact remains that we still need to educate people about the benefits of WWR," says Reiterman. "There has been lots of misinformation about wire and additionally many just aren't aware of all the advancements in technology that have occurred over the past few years. Simply put, welded wire reinforcement is a better alternative to rebar and builders that want to save time and money, whether they are building a concrete house or just placing a foundation, should consider it."

For more information on welded wire reinforcement, you can contact WRI at (800) 552-4WRI [4974]. Also, visit WRI's website at www.wirereinforcementinstitute.org.