Hurricanes and storms leading to floods have caused damages worth billions of dollars across Florida, especially in the past decade. Florida local jurisdictions have been overseeing the management and planning of development in flood zone areas.
All developments in flood hazard areas are overseen by the Federal Emergency Management Agency (FEMA).
An owner, contractor, or authorized personnel intending to renovate, construct, repair, move or demolish any property or building is required by the code to apply to the building official to obtain the corresponding permit. An application should be accompanied by a site plan that details the scope of the construction/development, the location, information on whether the construction is for an existing structure or entirely new, the street grades, finished grades, flood hazard areas, and design flood elevations.
Specific requirements pertinent to preventing future flood damage have to be met to obtain the permit from the jurisdiction. This is where the Florida Building Code (FBC) plays a crucial role in helping the contractors and design professionals to address the required design and other applicable standards.
Minimum flood based plan review criteria for buildings
Site requirements: Flood hazard areas, flood zones, and design flood elevations
Structural requirements: Includes flood requirements aligning with Section 1612, lowest floor elevations, enclosures, and flood damage-resistant materials.
Design flood elevation for electrical, plumbing, mechanical, and gas
Design flood elevation is the elevation of the highest existing grade of the structure’s perimeter plus the depth number (in feet) as per the flood hazard map.
Structural requirements include flood hazard areas, flood zones, design flood elevations, lowest floor elevations, enclosures, equipment, and flood damage-resistant materials.
An elevation certificate must be submitted to the corresponding authority with jurisdiction for construction in a flood zone. Furthermore, a final certification for the lowest floor elevation should also be submitted as part of the final inspection.
The standards relating to construction also vary by the flood zone rating. The main flood zone ratings are type A flood zone and type V flood zone.
Type A Flood Zone: the areas that are a bit more inland from coastlines and expect a static rise in water levels are categorized as type A flood zone.
Type V Flood Zone: Areas with proximity to the coastline are V zoned. “V” stands for velocity that relates to the velocity or force of the breaking waves. V zoned areas have stringent building standards.
For permitting reasons, the Base Flood Elevation (BFE) levels are calculated. The BFE is the minimum height above the sea level floodwaters can rise. BFE forms the standard references for both the building elevations and flood insurance. Building codes usually require the structure to be at least one foot above the corresponding BFE value, called the Design Flood Elevation (DFE).
Construction norms in flood zones
According to BFE, the structure must be elevated to leave useable space between the ground and the house floor. This space is deemed non-habitable and may only be used for storage and parking.
There are specific criteria to be met while enclosing such habitat:
- Approved flood vents of proper size and design
- Construction featuring flood-resistant materials
- No interior finishes, for example, plywood flooring and drywall
- Space should be strictly used for only limited storage. Limited storage means storing small-sized equipment, including lawnmower, garden house, and tires, and does not apply to kitchen appliances, including refrigerators, freezers, furniture.
- Elevation certificates before, during, and post-construction
The construction in the V zone requires all the criteria featured for the A Zone construction plus the construction of Breakaway walls.
Breakaway walls are constructed to give way to high-force waves by preventing the force of the waves from being exerted on the whole building structure. Once the walls break away, water can roll back and forth with minimum pressure exerted on the building.
It is mandatory to keep the breakaway walls free from any attachments of fittings, especially electrical wires and plumbing pipes. It is also important to stack items against breakaway walls that would prevent the walls from breaking away.
There are multitudes of standards and building code requirements that need to be considered and met to obtain building permitting in flood zone areas. This makes the permitting application, planning, and design process complex. Even the smallest decision you make during the application process can impact the approval process with the corresponding jurisdiction and the insurance agency. This is why it is highly recommended to hire professionals to handle construction, renovation, or demolition in flood zone areas.