Alternative A: Require Nonconversion Agreements for Enclosures Under Elevated Buildings

Enclosures Under Elevated Dwellings: Nonconversion Agreement, Prohibit Enclosures,Limit Size, Prohibit Partitions – local technical code amendments (FBC, Residential)

Alternative A: require Nonconversion Agreements for enclosures under elevated buildings (or dwellings)

Alternative B: limit the size of enclosures under elevated dwellings

Alternative C: prohibitpartitions in enclosures under elevated dwellings

Alternative D: prohibit enclosures under elevated dwellings

Description: The NFIP regulations and the Florida Building Code allow enclosing areas under elevated buildings with walls. Any enclosed area shall be limited to use for parking of vehicles, storage, and building access. Several requirements apply to the walls of enclosed areas, including specific requirements depending on the flood zone:

In Zone A, walls are required to have flood openings; and
In Zone V, walls are required to break away under certain flood loads.

NFIP flood insurance coverage (structure and contents) for enclosed areas is limited andis more expensive if enclosures are 300 square feet or more in area.

Nonconversion agreements: Communities may elect to require nonconversion agreements for all enclosures (i.e., independent of the other alternatives described here or combined with these alternatives). The objective is to reduce the likelihood that owners, including future owners, might convert enclosures to uses other than permitted uses. Please see the model nonconversion agreement developed by DEM and available on the building code resources webpage: However, please note that to qualify for the most CRS credits, the nonconversion agreement must include a statement that the owner agrees that the property can be entered and inspected at any time (note thatif this option is desired, the DEM model nonconversion agreement will need to be modified to accomplish this). Some CRS credits are provided for requiring nonconversion agreements even if the agreement does not include a statement regarding inspections.

Prohibiting enclosures: The benefits include lower flood insurance costs, less debris in floodwaters, fewer obstructions to the free flow of floodwaters, and no enclosed area that could be modified to a non-permitted use.

Limiting size: The benefits include lower flood insurance costs, less debris in floodwaters, fewer obstructions to the free flow of floodwaters, and smaller enclosed areas are less likely to be modified to a non-permitted use.

Prohibiting partitions: Enclosed areas without partitions are less likely to be modified to a non-permitted use. In addition, in Zone V, walls of enclosures are required to break away under flood loads and the presence of partitions may diminish or interfere with that performance.

How the FBC, Residential addresses enclosures: The FBC includes the basic, NFIP-consistent requirements for enclosed areas and walls below elevated buildings. Requirements for all flood zones are in R322.1, requirements for Zone A are in R322.2, and requirements for Zone V are in R322.3.

NOTE: The alternatives drafted below are only for the FBC, Residential and thus would apply only to one- and two-family dwellings and certain townhomes (see the scope of the residential code). These code amendments shown belowdo not affect buildings within the scope of the FBC, Building. Changes to FBC, BuildingSection 1612 would be necessary to extend these limitations to all buildings. Contact DEM if the intent is to apply these higher standards to all buildings.

Please see the General Instructions for Higher Standards. If you have questionsand to submit your draft ordinance for review, contact

ALTERNATIVEA. Use this amendment to require declarations of land restriction (nonconversion agreements) for enclosures. This is drafted to apply to all buildings in flood hazard areas that have any enclosures with more than {your selection} feet of “head room.” It may be modified to apply only to dwellings.

Step A-1. See the General Instructions to select the appropriate Whereas clause(s). Insert the following brief description of the higher standard:

to require declarations of land restriction (nonconversion agreements) for enclosures below elevated {select one: buildings / dwellings}

Step A-2. Add the following definition to the Floodplain Management Ordinance:

Declaration of Land Restriction (Nonconversion Agreement). A form signed by the owner and recorded on the property deed in Official Records of the Clerk of Courts, to agree not to convert or modify in any manner that is inconsistent with the terms of the building permit and these regulations, certain enclosures below elevated buildings.

Step A-3. Add the following to Section 3 of the ordinance where there are other local administrative amendments to the FBC. Note that requiring nonconversion agreements adds to items required to be submitted with permit applications which are reviewed by building officials. If theintent is to require nonconversion agreements only for dwellings, do not include the change to the list for commercial buildings:

107.3.5 Minimum plan review criteria for buildings.

Commercial Buildings: Building

8. Structural requirements shall include:

Flood requirements in accordance with Section 1612, including lowest floor elevations, enclosures, declaration of land restriction (nonconversion agreement), flood damage-resistant materials.

Residential (one- and two-family)

6. Structural requirements shall include:

Flood hazard areas, flood zones, design flood elevations, lowest floor elevations, enclosures, declaration of land restriction (nonconversion agreement), equipment, and flood damage-resistant materials.

ALTERNATIVEB. Use this amendment to limit the size of enclosures under elevated dwellings.

You may select the size limit – because NFIP flood insurance is more expensive for enclosures that are 300 sq ft or more in size, many communities elect to use a size limit of 299 sq. ft. (or less) to decrease the likelihood of enclosures being just slightly larger than the 300 sq. ft. trigger.
In Zone A, this also limits the size of crawlspaces, except crawlspaces that are less than a certain height (you may select the height; 4 ft seems reasonable). The intent is to dissuade future owners from excavating “taller” crawlspaces to add usable area, which would create basements, which are not permitted.
In Zone V, this additional language limits the size of all enclosures – even enclosures surrounded by insect screening or open lattice because they could be modified in the future to have solid walls.
To apply in only Zone V, the Whereas clause should be modified to replace “flood hazard areas” with “coastal high hazard areas” and then use only the text for R322.3.5 shown below.

Step B-1. See the General Instructions to select the appropriate Whereas clause(s). Insert the following brief description of the higher standard:

to limit the size of enclosures below elevated dwellings

Step B-2. Add a new Section 4 to the ordinance package to adopt local technical amendments to the FBC, Residential as follows. (Section 3 of the model ordinance package already contains local administrative amendments to the FBC, B.) Because these amend the FBC, you must retain underline and strikethrough as shown.

SECTION 4. The Florida Building Code, Residential is hereby amended by the following technical amendments.

R322.2.2 Enclosed area below design flood elevation. Enclosed areas, including crawl spaces, that are below the design flood elevation shall:

1.Be used solely for parking of vehicles, building access or storage.

2.Be provided with flood openings that meet the following criteria:

2.1. There shall be a minimum of two openings on different sides of each enclosed area; if a building has more than one enclosed area below the design flood elevation, each area shall have openings on exterior walls.

2.2. The total net area of all openings shall be at least 1 square inch (645 mm²) for each square foot (0.093 m²) of enclosed area, or the openings shall be designed and the construction documents shall include a statement by a registered design professional that the design of the openings will provide for equalization of hydrostatic flood forces on exterior walls by allowing for the automatic entry and exit of floodwaters as specified in Section 2.6.2.2 of ASCE 24.

2.3. The bottom of each opening shall be 1 foot (305 mm) or less above the adjacent ground level.

2.4. Openings shall be not less than 3 inches (76 mm) in any direction in the plane of the wall.

2.5. Any louvers, screens or other opening covers shall allow the automatic flow of floodwaters into and out of the enclosed area.

2.6. Openings installed in doors and windows, that meet requirements 2.1 through 2.5, are acceptable; however, doors and windows without installed openings do not meet the requirements of this section.

3. Be not more than {insert number} sq ft in area, except for crawlspace foundations that have a wall height less than {insert number} feet.

R322.3.5 Enclosed areas below design flood elevation. Enclosed areas below the design flood elevation shall be not more than {insert number} sq ft in area and shall beused solely for parking of vehicles, building access or storage.

ALTERNATIVEC. Use this amendment to prohibit partitioning of enclosures under elevated dwellings.

To apply in only Zone V, the Whereas clause should be modified to replace “flood hazard areas” with “coastal high hazard areas” and then use only the text for R322.3.4 and R322.3.5.

Step C-1. See the General Instructions to select the appropriate Whereas clause(s). Insert the following brief description of the higher standard:

to limit partitioning of enclosed areas below elevated dwellings

Step C-2. Add a new Section 4 to the ordinance package to adopt local technical amendments to the FBC, Residential. (Section 3 of the model ordinance package already contains local administrative amendments to the FBC, B.) Because these amend the FBC, you must retain underline and strikethrough as shown.

SECTION4. The Florida Building Code, Residential is hereby amended by the following technical amendments.

R322.2.2 Enclosed areas below design flood elevation. Enclosed areas, including crawl spaces, that are below the design flood elevation shall:

Be used solely for parking of vehicles, building access or storage. The interior portion of such enclosed areas shall not be partitioned or finished into separate rooms except for stairwells, ramps, and elevators. The limitation on partitions does not apply to crawlspace foundations.

Remainder unchanged

R322.3.4 Walls below design flood elevation. Walls and partitions are permitted below the elevated floor, provided that such walls and partitions are not part of the structural support of the building or structure and:

Electrical, mechanical, and plumbing system components are not to be mounted on or penetrate through walls that are designed to break away under flood loads; and
Are constructed with insect screening or open lattice; or
Are designed to break away or collapse without causing collapse, displacement or other structural damage to the elevated portion of the building or supporting foundation system. Such walls, framing and connections shall have a design safe loading resistance of not less than 10 (470 Pa) and no more than 20 pounds per square foot (958 Pa); or
Where wind loading values of this code exceed 20 pounds per square foot (958 Pa), the construction documents shall include documentation prepared and sealed by a registered design professional that:

4.1. The walls and partitions below the design flood elevation have been designed to collapse from a water load less than that which would occur during the design flood.

4.2. The elevated portion of the building and supporting foundation system have been designed to withstand the effects of wind and flood loads acting simultaneously on all building components (structural and nonstructural). Water loading values used shall be those associated with the design flood. Wind loading values used shall be those required by this code.

R322.3.5 Enclosed areas below the design flood elevation. Enclosed areas below the design flood elevation shall be used solely for parking of vehicles, building access or storage. The interior portion of such enclosed area shall not be partitioned or finished into separate roomsexcept for stairwells, ramps, and elevators.

ALTERNATIVED. Use this amendment to prohibit enclosures, including crawlspaces, below elevated dwellings.

To apply in only Zone V, the Whereas clause should be modified to replace “flood hazard areas” with “coastal high hazard areas” and then use only the text for R322.3.4 and R322.3.5 shown below.
Contact DEM if the intent is to prohibit enclosures in all Zone A for parking, storage, and building access, but to permit perimeter wall foundations (crawlspaces).

Step D-1. See the General Instructions to select the appropriate Whereas clause(s). Insert the following brief description of the higher standard:

toprohibit enclosures below elevated dwellings

Step D-2. Add a new Section 4 to the ordinance package to adopt local technical amendments to the FBC, Residential as follows. (Section 3 of the model ordinance package already contains local administrative amendments to the FBC, B.) Because these amend the FBC, you must retain underline and strikethrough as shown:

SECTION 4. The Florida Building Code, Residential is hereby amended by the following technical amendments.

R322.2.2 Enclosed area below design flood elevation. Enclosed areas, including crawl spaces, that are below the design flood elevationare not permitted.shall:

1.Be used solely for parking of vehicles, building access or storage.

2.Be provided with flood openings that meet the following criteria:

2.3. The bottom of each opening shall be 1 foot (305 mm) or less above the adjacent ground level.

2.4. Openings shall be not less than 3 inches (76 mm) in any direction in the plane of the wall.

2.5. Any louvers, screens or other opening covers shall allow the automatic flow of floodwaters into and out of the enclosed area.

R322.3.4 Walls below design flood elevation. Walls and partitions are not permitted below the elevated floor., provided that such walls and partitions are not part of the structural support of the building or structure and:

1Electrical, mechanical, and plumbing system components are not to be mounted on or penetrate through walls that are designed to break away under flood loads; and

2Are constructed with insect screening or open lattice; or

3Are designed to break away or collapse without causing collapse, displacement or other structural damage to the elevated portion of the building or supporting foundation system. Such walls, framing and connections shall have a design safe loading resistance of not less than 10 (470 Pa) and no more than 20 pounds per square foot (958 Pa); or

4Where wind loading values of this code exceed 20 pounds per square foot (958 Pa), the construction documents shall include documentation prepared and sealed by a registered design professional that:

4.1. The walls and partitions below the design flood elevation have been designed to collapse from a water load less than that which would occur during the design flood.

R322.3.5 Enclosed areas below design flood elevation. Enclosed areas below the design flood elevationare not permittedshall be used solely for parking of vehicles, building access or storage.

Higher Standard: Enclosure Limits (101413) 1