Floodproofing

Commercial Buildings [ASCE 24-14, Sec. 6 and C6]

Dry Floodproofing

Dry Floodproofing is surrounding a building with barriers and sealants to higher than expected minimum flood levels to keep water from entering a building.

Dry floodproofing consists of sealed walls and foundations, anti-buoyancy measures with specially constructed watertight metal panels for doors and windows. Such measures need to extend at least one foot above the minimum flood level for any particular location (the Base Flood Elevation or BFE).

Wet Floodproofing

Wet Floodproofing is designing a building to allow flood waters to freely enter and leave a building without causing damage.

Floodproof Versus Elevation

Only non-residential use buildings may be floodproofed in lieu of elevation, such as stores, offices, restaurants and etc. Such measures are usually applied to solid construction buildings, as wood-framed buildings are nearly impossible to floodproof to any acceptable degree. Floodproofing isn’t permitted for commercial buildings used for residential purposes, such as:

  • Apartments
  • Areas of hospitals/medical facilities where patients are housed
  • Child/elder day care
  • Motels and hotels
  • Sleeping rooms for rent/lease

A-Zones Only

Floodproofing isn’t permitted for buildings in or straddling "V" flood zones nor Coastal A Zones.

Florida Building Code

The floodproofing requirements/standards won’t be found within the 2010 Florida Building Code. This code incorporates a third-party standard, the American Society of Civil Engineer’s (ASCE) publication Number 24-14, Flood Resistant Design and Construction. The relevant floodproofing chapters are sections 6 and 6C. Due to copyright protections, the City isn’t permitted to publish this booklet online.

Local Floodproofing Review Process Update

February 10, 2015: With flood panel manufacturers withholding shop drawings and load calculations until the panels have been purchased, this created an obstacle for local permitting review. As a result, the City’s review process has been amended to show what documentation is needed during the two approval phases: Permitting and Final inspection. Now, the manufacturer’s documentation won’t be required until the project is completed and awaiting final inspection.

Floodproofing Approval Phase Requirements

Plan Review/Permitting Phase

  • Any soil or fill adjacent to the structure compacted and protected against erosion and scour
  • Building Plans w/general floodproofing overview, showing:
    • Relevant flood zones identified
    • Flood zones plotted on site plans
    • BFE, DFE and Grade elevations shown
    • Height of floodproofing relative to DFE
  • Elevation Certificate (original, not copy)
  • Emergency ingress/egress above floodproofing during flood conditions
  • Floodproofing Certificate (construction drawings phase; original)
  • Floodproofing Panels
    • Locations
    • Sizes
    • Types
  • Sewerage backflow prevention measures
  • Show materials below DFE - not protected by floodproofing - are resistant to salt water flood damage
  • Show that walls are substantially impermeable to the passage of water.
    • With load calculations
  • Show that walls, floors, and flood shields shall be designed and constructed to resist hydrostatic, hydrodynamic, and other flood-related loads to relevant elevation.
    • Including the effects of buoyancy resulting from flooding to the elevation.
  • Statement plans in accordance with ASCE 7 and 24-14
    • Satisfies "combination of loads" requirement

Final Inspection/Certificate of Occupancy Phase

  • Emergency Operation Plan
  • Floodproofing Certificate (finished construction phase)
  • Inspection and Maintenance Plan
  • Local agency review/inspection
  • Shop drawings for each flood panel type w/load calculations
    • Certified by a State of Florida licensed Engineer

Rejected Floodproofing Plans Update

Recently, Federal Emergency Management Agency (FEMA) rejected a couple of floodproofing plans for technical compliance issues. An excerpt is viewable here, so those designing floodproofing will know to address these concerns upon submission, so they aren’t rejected later for these same reasons.

Floodproofing Documents