If you are someone preparing to build a new home in a hurricane-prone region, you may be wondering which building material is best for a hurricane-proof home. When we ask that question, we are usually referring to the frame (skeleton) of the house. The decision of what material to use in the framing of a house is an important one, and there are several factors that go into that decision. Those factors include material cost, performance, and ease of construction. For those of us who live in a coastal area, material performance is of particular importance, but other factors must also be considered. This article compares two building materials for building a house in a hurricane-prone area. Most people will assume that wood is the only option for residential construction, but I encourage you to at least weigh the benefits of one concrete solution or another.
Wood
When we talk about wood construction, we are mainly referring to conventional wood construction using dimensional lumber and plywood. The frame is constructed of studs, beams, and joists. Conventional timber construction is done in situ (built with rods) or partially in a workshop (prefabricated). Examples of prefabricated wood construction include wood-frame or job-delivered, shop-built modular homes. The modular home industry is growing and is even being traded into the high end housing markets. Other wood construction methods include heavy wood framing and structural insulated panels.
The biggest benefit of wood construction is its relative cost. Houses can generally be built less expensively with wood than with other material options. This is the main reason why construction with wood is so prevalent. Wood has been around for years and has proven to be a viable building material to withstand the weather. However, like any building material, when not built or designed correctly, wood has fallen short in the face of hurricanes. So it is possible to build a house to withstand hurricane force winds, but some steps must be taken to ensure it is designed and built correctly. An employer once told me that the most important thing to consider when designing with wood was the connections. Connections are king when it comes to wood, so pay special attention to this area. Most building departments require some engineering to be done to ensure connections and other critical items are tested before a permit is issued for the house.
Concrete
When it comes to performance, there are many benefits to building a house with concrete. Concrete is strong, resistant to fire, decay, termites, and mold. This material is truly sustainable, and that includes withstanding a hurricane. This, of course, assumes that the material is designed and installed correctly. Concrete construction can be built using forms or using pre-formed units (also known as masonry or blocks).
The most basic method of installing concrete is to build plywood forms and then concrete walls and floors, which rest on a concrete base. The steel reinforcement is placed inside the formwork before the concrete is poured. Forming the concrete can be labor intensive and therefore cost prohibitive. Insulated Concrete Forms, or ICFs, are a solution that has been developed to make concrete a more viable option for residential construction. The forms consist of Styrofoam, which is lighter and easier to erect than plywood forms. Concrete masonry unit (CMU) construction consists of pre-formed hollow concrete blocks that are stacked in place, filled with steel reinforcement, and then grouted on-site. CMU is also commonly, and incorrectly, known as cinder block. This method is widely accepted in Florida for hurricane-proof construction due to its reasonable cost compared to the strength the material provides.
A slight deviation from CMU is AAC, which stands for Autoclaved Aerated Concrete. AAC is a lightweight aerated concrete that is also preformed into standard size blocks, which can be stacked in place and then filled with steel reinforcement and grouted on site. AAC is a construction material that is relatively new to the United States. AAC is gaining in popularity because it is lightweight, saves energy, and is relatively easy to cut and install. I have seen vendor details showing threaded rod systems used within the blocks, but I would not recommend this practice. Rebar designed to work with concrete should be used inside AAC units, not threaded rod.
I believe that concrete, whether it’s formed-in-place concrete or concrete masonry, has inherited strength benefits that naturally withstand hurricane force winds. In addition to a concrete option, it will bring other benefits such as resistance to mold, fire and termites, as well as energy efficiency. Any of these concrete options will likely be slightly more expensive than wood when evaluated based on initial cost. That being said, it should be noted that the cost over the life of the material must be considered, in addition to the initial cost. For example, a wooden house typically costs more to insure than a concrete house. Also, some states have tax deductions for the use of energy efficient materials like AAC. Finally, you must place some value on the increased risk that a wooden home may not perform as well in a hurricane as a concrete home.
When making your decision about which material to use to build your hurricane-proof home, you’ll likely compare cost, performance, and other factors. Don’t just assume that what everyone around you is doing will be enough for your home. Keep in mind that there are options to choose from, and it’s important to consider which option is best for your home and preferences. Lastly, remember that price is important, but building a house the wrong way can cost you down the line.