Design Techniques for Storm Resilient Communities
By: Kevin Paul, AIA, NCARB, LEED AP, CFM | Senior Vice President & Discipline Director, Private Sector Real Estate at H2M architects + engineers
Rising sea levels and worsening storms continue to pose major difficulties for Florida’s residential real estate market, with last year’s hurricanes—particularly Helene and Milton—causing tens of billions of dollars in property damage. Given the rapidly shifting priorities of Florida’s real estate market, developers are placing a greater emphasis on building new storm-resilient communities. Homes in these developments use a variety of technologies and techniques, including locating all utility lines underground and doing a better job securing homes to their foundations.
These innovative storm-resilient home designs are poised to help revitalize Florida’s residential real estate market in the wake of unaffordable insurance premiums and the recent record-high migration of Floridians into other states. Different communities will have different storm resiliency needs depending on factors such as topography, coastal exposure and ground surface permeability, but there are a few design measures that should always be taken when building storm-resilient residences and developments.
Elevate and Reinforce Your Property
For residential properties, one of the most universal precautions one can take to improve storm resiliency is to elevate their property’s primary function spaces (such as kitchen, living room, and dining room areas). The ideal elevation will differ from location to location, as it is largely dependent on flood risk. The Florida Building Code already requires that the lowest floor of every building be at least one foot above the base flood elevation (BFE), a metric of flood risk determined by the area’s historical flood data. However, as BFE only accounts for historical flooding, property owners are advised to raise their property above the design flood elevation (DFE), a higher elevation standard that accounts for additional factors that might contribute to flooding, such as water run up, wave action, and bridge openings. All mechanical equipment, ductwork, and electrical panels should also be set at or above the DFE.
Property owners should also secure any items sitting below the BFE or DFE, such as equipment in storage, to prevent them from becoming dangerous projectiles. Additionally, properties with elevated structural foundations, including decks, should be able to withstand at least 1,000 pounds of impact in the event that something does become a projectile. By adhering to the DFE and elevating important spaces and items above it, facility managers and homeowners can protect their most vital assets from both typical and atypical flooding events.
Implementing Floodproof Technology
Elevated, reinforced structures are still susceptible to damage from floodwaters; it is therefore equally important to invest in flood protection systems, which guard against floods by either blocking or redirecting the flow of water.
Systems designed to keep water out of a structure entirely are known as dry floodproofing measures and include technologies such as flood doors/windows and horizontal/vertical flood barriers. Both of these systems are capable of resisting the hydrostatic force of the floodwaters. In order to be classified as ‘wet floodproofed’, the system can allow no more than four inches of water to enter a space within a 24-hour period. Passive floodproofing measures require no human intervention, while active systems require advanced planning and implementation. Passive systems activate when rising floodwaters create enough pressure to raise a ‘floatation gate’ that seals against part of the permanent structure. As floodwaters reside, the ‘gates’ automatically go back to their pre-flood positions.
Dry floodproofing only works, however, if the walls and doors can actually withstand the large amounts of hydrostatic pressure placed upon them. Alternatively, wet floodproofing avoids this issue by utilizing vents and breakaway walls to redirect the floodwaters to spaces within the structure that are more resilient to water damage (such as a room with impermeable walls and floor). When floodwater is allowed to enter the structure, hydrostatic pressure equalizes both inside and outside, reducing the risk of structural failure from an overabundance of exterior pressure.
Per the U.S. Federal Emergency Management Agency, residential properties must be elevated and wet-floodproofed; owners of non-residential properties, however, have the option to implement either wet or dry floodproofing.
Consult with a Floodplain Manager
Consultants with a Certified Floodplain Manager (CFM) certification from the Association of State Floodplain Managers are adept at crafting flood resiliency plans based on factors such as topography, flood history, ground surface permeability, structural integrity, and any other specific needs the property owner may have. Even as these increasingly powerful storms threaten communities in Florida, there are a number of effective mitigation methods available to protect you, your family, and your property from the worst of it.