Resilient Construction

Following the flooding from Hurricanes Helene and Milton in 2024, owners of flooded homes had to make the following decision; whether to:

1. Renovate the house and return it to its previous state and/or improve it 
   • This is subject to the FEMA 50% rule:  code does not allow you to spend more than 50% of the appraised or assessed value of a non-conforming structure per year without fully bringing it up to current building code compliance
2. Elevate the house, putting garage and storage space underneath 
   • This is an expensive option, but it is quicker and costs less than tearing down and rebuilding
3. Tear down the house and re-build a new elevated house or a slab-on-fill house
4. Sell the damaged house and let someone else deal with it

Regardless of the type of house, we encourage all homeowners to use waterproof materials in non-conforming spaces.  When renovating, try to conform with current building codes as much as possible.  Use pressure-treated framing and waterproof flooring, wallboard, doors, and trim.  Raise power outlets.  Elevate outside pool, HVAC, and other equipment.  The goal should be to recover from future flooding events as quickly (and inexpensively) as possible. 

There are two approaches to floodproofing:

1. "Wet Floodproofing" = allow water IN, through flood openings (vents), to equalize hydrostatic pressure, started being required in new residential construction in the late 1970's and incorporated in the Florida Building Code in 2002
2. "Dry Floodproofing" = keep water OUT, up to a certain height, allowed for commercial new construction (but not residential), requires:

• Reinforced walls designed to resist hydrostatic and hydrodynamic loads, certified by an engineer
• Wall sealants/membranes to prevent seepage
• Removable watertight shields that can be placed over windows and doors
• Heavy-duty sump pump with backup power to remove water that leaks through shields

​Why did flood openings (vents) start being required for new residential construction in the late 1970's? Because the forces exerted by flood waters were collapsing walls! Apparently, even a few feet of water can generate thousands of pounds of force per wall.

Since the 2024 hurricanes, there has been a lot of talk about installing temporary flood barriers to keep water out of existing residential and commercial structures. But, according to building code for new commercial construction, these removable shields by themselves are insufficient, and are not even allowed for new residential construction as an alternative to flood openings.

We know from 2024 that flood water over-topped window sills and came up through concrete floors and drains. So, by going through the effort and expense of purchasing removable flood barriers, installing the brackets to hold them in place, and storing the panels/shields:

• In the best case, flood water may still get into the structure. 
• In the worst case, the structural integrity of a home or building may be in jeopardy.

Flood Resistant Provisions in the 8th Edition Florida Building Code (2023)