Flood-resistant construction in Florida is gaining traction due to new building codes, but it still faces many challenges and may only be practical for some.
What is Flood-Resistant Construction?
Flood-resistant construction refers to construction practices that aim to prevent flood water from entering a property or, if unavoidable, to minimize the damage to the property. You see these construction practices applied in flood plains and other areas at a higher risk of flooding via rainfall and rising sea levels.
Flood plains only tell part of the story. Federal Emergency Management Agency (FEMA) updates its maps to incorporate multiple flood risks. So it’s vital that individuals and construction professionals in Florida, even if they are not living or building on a flood plain, should start looking into flood-resistant construction.
Flood-Resistant Construction: Materials and Practices
The two main facets of flood-resistant construction are materials and construction practices. The construction practices may include:
- The structure is elevated above the flood level. One common way to do it is to build the home over stilts (pier foundations) that are tall enough to keep the structure above the floodline. They usually have ample space to let the flood water through, and even if there are walls, they are typically all-block with flood vents to provide a passage being elevated e to the water so that it doesn’t push against the walls with full force. The materials used to build these stilts are another point of consideration.
- It’s important to note that elevating the structure above flood level via stilts/piers is one of the dry flood-proofing techniques FEMA recommends. There are others, all adhering to the basic guideline that the lowest floor or flood-proofed area should be two feet above the Base Flood Elevation (BFE), available for different zones in FEMA’s Flood Insurance Rate Map (FIRM).
- Wet flood-proofing is more than just a construction practice and also covers temporary measures that apply to a structure to allow the flood water to pass through without damaging the interior or design much. The construction practices include protecting service equipment and plumbing from flood water, typically through installation above the flood line and insulation.
- Construction practices to avoid flood-related long-term damage, like mold.
The other important facet of flood-resistant construction is the materials used in the structure. Flood resistance is not just about the direct impact of flood water hitting the building. It’s also about flood water’s effect on facilities when it stands still in and around structures for weeks with no way to drain.
Many materials can withstand flood water with minimal damage if it just comes and goes (unless ample momentum and power are pushing it). Still, the damage can be significant if those materials are in contact with the water for days or weeks.
Florida Building Code Flood-Resistant Provisions
There are several provisions in the Florida building code pertaining specifically to flood-resistant construction practices and the usage of flood-resistant construction materials. Published in 2020; the latest edition applies to almost all buildings except detached one- and two-family homes and multi-family homes with less than three stories. The problem is that these exceptions include the bulk of the buildings in the state.
The code defers FEMA’s list of acceptable building materials published in 2008 for what’s permitted and items that are not approved. This list mentions two classes of proper flood-resistant construction materials and three classes of unacceptable materials. The two acceptable classes are:
● Class-5 - Highly resistant to flood water damage: It includes concrete, concrete blocks, clay tile, and marine-grade plywood.
● Class-4 - Resistant to flood water damage: It includes clay-brick, certain plywood classes, and most solid wood types.
It would be unfair to say that Florida’s building codes haven’t helped shape the construction industry for the better and triggered the correct flood-resistant construction practices and choices. It has kick-started the trend of “high-and-dry” construction, but that’s often detrimental to the surrounding/neighboring homes/structures that are often not at the same elevation.
Practical Considerations For Flood-Resistant Constructions in Florida
How practical flood-resistant construction is in Florida depends upon several factors, including the following:
Regardless of how impactful/valuable it is, most new buildings must adhere to the building codes requiring elevation and keeping the critical systems above the expected flood levels.
Considering the shifting focus on rising sea levels and its impact on the frequency and intensity of flooding, the building codes may become more comprehensive regarding flood-resistant construction.
It’s essentially a mandatory consideration, not a practical one, because most individuals/entities responsible for new construction must comply with the state’s flood-resistant construction requirements, which may be stricter in flood-prone areas.
Flood-resistant construction practices are more accessible on smaller structures like single-family and two-family homes and are more complex and expensive for oversized buildings. Elevating larger and heavier buildings above the expected flood levels without negatively impacting their structural integrity can be quite costly.
However, elevated flood-resistant structures are under construction, and even if there’s no way to upgrade them, more significant buildings can adopt other flood-resistant features like unique drainage systems and use denser concrete to resist flood damage.
However, it’s far more practical for smaller housing units, and we may see flood-resistant construction trends catching on in the construction of most new one to two-family homes and smaller multi-family buildings.
Wood and wooden construction materials are still prevalent in Florida because of easy availability, cost, and aesthetics, though the trend is shifting. Concrete is the natural alternative, but other flood-resistant materials, like 3D cementitious sandwich panels, have yet to catch on.
As newer technologies and materials become cheaper, more readily available, code-compliant, and properly adopted by construction professionals, flood-resistant construction (using them) may become more commonplace and practical in Florida.
The most significant consideration when it comes to flood-resistant construction is the cost. The best flood-resistant construction practices and materials cost the most and can significantly increase the overall construction cost. More builders will likely adhere to the bare minimum requirements of the building codes to keep costs low.
It may offer some resistance/protection against flooding. However, running an accurate cost-benefit analysis on how much damage these and the best-in-class flood-resistant construction practices and materials will prevent is challenging. In addition, this becomes even more complex if we consider the flood insurance variable.
Flood-resistant construction is catching on in Florida, partly because of the building codes and because developers realize it will be a significant selling point. However, costs and available technologies/materials are still an issue, and the building code may need a round of revisions for a more comprehensive flood-resistant practice.
Furthermore, even with a flood-resistant construction, you may still have to bear the astronomical costs of flood insurance, especially if you are in a high-danger zone. Still, it’s better to be safe on two separate levels (flood-resistant construction and insurance) than one, especially if the risk of flooding is high enough.
This article is for informational purposes only. It should not be considered financial, real estate, or legal advice. The market fluctuates; therefore, not all information will remain the same. Consult a financial or real estate attorney before making significant real estate decisions.