October 09, 2018

Five Flood-Resistant Building Materials

According to the Federal Emergency Management Agency (FEMA), there have been at least 26 significant flood events that have impacted Texas in the past 40 years, not including the high number of flash and river floods. To help combat these disasters, Texas builders are following FEMA’s guidance by creating flood-resistant structures whenever possible.

FEMA has issued a recommendation to build with flood damage resistant materials to minimize the time-consuming and costly process of rebuilding after flood damage. Building materials are considered flood-resistant if they can withstand direct contact with flood waters for at least 72 hours without being significantly damaged.

These five flood-resistant building materials are recommended by The Association of State Floodplain Managers to protect your next project and the people who live or work there.

1. Naturally Decay-Resistant Lumber

Photo: Windsor Plywood

The most common building material is, of course, lumber. While you may think wood and water don’t mix, there are actually several types of wood that are naturally resistant to decay.

For instance, western red cedar and redwood are naturally decay-resistant. Both types of wood, however, can split when driving fasteners into the wood. Also, both can bleed tannins that appear as stains around fasteners which can show through painted surfaces. To combat this, make sure to follow proper prepping procedures to ensure the wood will accept wood stains and clear finishes.

Cypress is another decay-resistant option that grows in swamps and accepts stains and clear finishes.

White oak is much less porous, decay-resistant and very strong. However, it does split easily like redwood and cedar, so you should predrill screw holes for fasteners.

Composites offer another option if you want the look of wood without the splintering issues wood can bring. Made from thermoplastic resins, wood flour and wood fiber, composites have no defects and do not compress like wood. It also doesn’t warp, crack or rot. Although composites come in a variety of colors, composite wood doesn't absorb paint and stain, so it can’t be as customized as wood.

2. Marine-Grade Plywood

Photo: J. Gibson McIlvain Company

Marine-grade plywood is hardwood plywood made with waterproof glue, which allows the wood to retain its integrity, so, if exposed to moisture, the glue won't fail and the wood layers won't fall apart.

Standard plywood products can be found at hardware stores, but even the best-rated plywood at a hardware store isn’t as high quality as marine-grade. Standard panels are generally made with thicker layers of softwood, which can create voids or holes in the center of the wood which is undetectable until you cut into the panel.

Marine plywood, on the other hand, is made from hardwoods. It’s created with thin layers of 100 percent hardwood to make it stronger, harder and with a finer grain. However, the wood itself is not naturally waterproof unlike the glue used to create it. When used in a flooding area, it must be protected by a strong water-resistant finish.

3. Closed-Cell Foam Insulation

Photo: Certain Teed

Spray foam insulation is commonly used to increase a home’s energy efficiency and maintain year-round comfort – all while offering quick application and ease of use in hard to reach spots. However, not all spray foam is created equal.

Closed cell foam is denser and offers higher R-values than other types of foam — around 6.0 per inch, although some higher performing formulations have R-values of 7.14 per inch and higher. Because of its increased resistance, closed cell foams feature better insulation and are more resistant to water degradation or penetration.

4. Metal Roofing

Photo: Drexel Metals, Inc

Heavy rains are often accompanied by strong winds. "Water penetration through or around otherwise intact openings from wind-driven rain can do a significant amount of physical damage, cause occupant displacement and business interruptions, and lead to extensive restoration expenses," cautions Dean Lewis, American Architectural Manufacturers Association. "It can also create a mold-friendly environment in unseen wall cavities and in spaces between exterior sheathing and cladding."

Fortunately, according to Mark Henry, a senior research engineer at Butler Manufacturing, wind-driven rain is usually not an issue for metal roof systems. "They are designed to be weathertight," he says. "The long interlocking roof panels do not provide a gap through which wind could drive rain into the building interior.”

5. Concrete

Photo: Bautex

What’s more solid than concrete? "With a single material, we can accomplish many things: energy efficiency, strength, durability, resilience, and safety," explains Dr. Jeremy Gregory, the executive director of the Concrete Sustainability Hub. Another benefit? Because of its chemical nature, concrete actually gets stronger over time, not weaker. There are four main types of concrete building systems used in the US:

●    Concrete Blocks: The traditional rectangular blocks are the most widely used concrete building system as they provide an affordable defense against hurricanes.

●    Removable Forms: Insulation and reinforcing steel are placed inside removable wall forms, made of aluminum, wood or steel, before concrete is poured into the forms. Once the concrete has cured, the forms are removed, leaving concrete walls filled with insulation and steel. This makes them especially resistant to high winds, as well as flooding.

●   Panel Systems: There are two types of panel system: precast concrete and site-cast concrete. With precast, the walls are made off-site, filled with steel, insulation and electrical wiring, before being moved to the project site and put into place with cranes. With site-cast concrete, the walls are created on site by pouring into a cast, but this method requires a very open area so the walls can be tilted into place once they are finished.

●    Insulating Concrete Forms (ICFs): ICFs are building blocks made of foam plastic or EPS-cement composite (a mixture of cement and expanded polystyrene) which makes a durable, energy efficient concrete block. The blocks are stacked and then filled with concrete. Some ICFs, such as Bautex Blocks, are FEMA rated against floods and hurricanes, as well as being energy efficient and fire rated (four-hour).

When you work in areas that see significant flooding, such as Texas, you need to be able to create buildings that will be able to survive water damage.  

To learn more about how the right building system can protect against floods, contact the experts at Bautex at [email protected] or sign up for updates on how Bautex Systems is transforming the built environment.