Resolution 234-20151
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MONROE COUNTY, FLORIDA
RESOLUTION NO. 234 - 2015
WHEREAS, Monroe County is currently a participating community in the National
Flood Insurance Program (NFIP) and is working on internal County policies to improve upon its
interpretation of NFIP regulations; and
WHEREAS, Monroe County desires to become eligible to enter FEMA's Community
Rating System (CRS); and
WHEREAS, Monroe County Code Section 122-2(c), in par� requires that in interpreting
other provisions • this chapter, the building official. shall be guided by the current edition of
FEMA's 44 CFR, and FEMA's interpretive letters, policy statements and technical bulletins as
9dopted by resolution from time to time by the board of county commissioners;
NOW, THEREFORE, BE IT RESOLVED BY THE BOARD OF COUNTY
COMMISSIONERS OF MONROE COUNTY, FLORIDA:
Section 1. Pursuant to Monroe County Code Section 122-2(c), the Board hereby adopt
FEMA Technical Bulletin I I "Crawlspace Construction" dated November 2001, a copy of whiii
�s attached hereto.
Section 2. The Clerk • the Board is hereby directed to forward one (1) certified copy of
this Resolution to the Building Department.
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PASSED AND ADOPTED by the Board of County Commissioners of Monroe County,
Florida, at a regular meeting held on the 16 Ih
• September, 2015.
Mayor Danny L. Kolhage
Yes
Mayorpro tem Heather Carruthers
Commissioner Sylvia Murphy
Commissioner George Neugent
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Commissioner David Rice
Yes
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Glossary at the end of this bulletin.
Key WordSubject Index Page
Any comments on the Technical Bulletins should be directed to:
Federal Emergency Management Agency
Eff few kUl-iVIN-i4
500 C Street, SW.
Washington, DC 20472
Wave design on cover based on the Japanese print The Great Wave Off Kanagawa, by Katsuchika Hokussai
(1760-1849), Asiatic Museum of Fine Arts, Boston.
National Flood Insurance Program Interim Guidance
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Wall Fie�t . ?jk Foundation Wail
Wall Height—j
r. Flood Vent
rawlspace
Interior Grade
Extoriw Grad
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Figure I Pr eferred crawlspace construction
Floor Joist
SF
Wall Height
h
Foundation Wall
Florid Vent
Lowest Adjacent
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Interior Gmde
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Figure 2 Below-grade crawlspace constriction.
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NFIEP Requirements for All Crawlspace Construction
Crawlspace construction is not permitted in V zones. Open pile or column foundations that
withstand storm surge and wave forces are required in V zones.
Any building utility systems within the crawlspace must be elevated above BFE or designed so that
floodwaters cannot enter or accumulate within the system components during flood conditions.
Ductwork, in particular, must either be placed above the BFE or sealed from floodwaters. For
further guidance on the placement of building utility systems in crawlspaces, see FEMA 348,
Protecting Building Utilities From Flood Damage.
Flood-resistant materials and utilities, access, and ventilation openings in crawlspaces are further
addressed in this bulletin.
F.To r K ITI MI,
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• Below-grade crawlspace construction in accordance with the requirements listed above will not be
considered basements.
Drainage considerations for below-grade crawlspaces are further addressed in this bulletin. For
additional information regarding this interim guidance, please contact the FEMA Regional Office or
State NFIP Coordinator. Local 1A regional offices are, listed in the &;�;,amtclM*iinted User's Guide
to Technical Bulletins and may be found at the www.fema.gov website.
Buildings in flood hazard areas may be subjected to a variety of flood-induced forces. During inundation
by standing or low-velocity floodwaters, a building must primarily resist hydrostatic pressures from
saturated soils and floodwaters. This situation is typical of broad, flat floodplains and floodways along
lower-gradient rivers and streams. During inundation by high-velocity floodwaters, a building must
also resist hydrodynamic forces and impact loads. High-velocity floodwaters are found in floodways
along steeper-gradient rivers, sheet flow down slopes, or coastal areas with storm surge and waves.
The community Flood Insurance Study contains a Floodway Data Table that includes data on mean
velocities (in feet per second) within the floodway at each cross section along the river or stream. The
mean averages the higher channel velocities with lower velocities in overbank areas that are within the
floodway. Generally, velocities at sites outside of the floodway are lower than the mean floodway
velocities listed in the Floodway Data Table. For example, if the mean floodway velocity at a cross
section is 4 feet per second, the velocities outside the floodway are likely less than that value. If in
doubt about the floodway velocity or in areas where the mean floodway velocity may exceed 5 feet
per second, contact an engineer knowledgeable in hydraulics and hydrology to determine flood
velocities at the building site.
Buildings located in areas subject to ponding or low-velocity flows must primarily address issues
related to hydrostatic loads on the crawlspace foundation, removal of floodwater and sediment from
the crawlspace area, and other NFIP floodproofing requirements, such as protecting or elevating
utilities and using flood-resistant materials.
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5 feet per second). Other types of foundations, such as open pile or column foundations, that allow
(loodwaters to flow freely beneath the building are recommended for these areas.
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Buildings that have below-grade crawlspaces will have higher flood insurance premiums than
buildings that have the preferred crawlspace construction, with the interior elevation at or above
the lowest adjacent exterior grade (LAG).
Best Practices for Crawlspace Foundations in SFHA
The NFTP preferred construction practice for excavated crawlspace construction is to backfill the
interior area so that it is level with or higher than the LAG. If trench construction is used to place
footings, the trenches should be backfilled to the level of the adjacent exterior grade, to avoid ponding
of water. A reinforced masonry or concrete foundation wall that is anchored to the footing and lowest
floor with connectors will provide the best performance in flood events. This type of construction will
better resist hydrostatic pressures against the foundation and limit the amount of water that will pond
under the building after a flood.
A community that chooses to allow the construction of below-grade crawlspaces should develop a
multi- hazard approach that also resists other loads from hazards such as wind and earthquake.
Crawlspace foundation walls must bear or resist all loads that may be experienced during their useful
service life.
Figure 4 Flood - related forces on a Crawlspace wall.
A significant issue associated with below-grade crawlspaces is drainage of the interior crawlspace are-,-�
after normal precipitation and flood events. Moisture damage to a building can be severe when water
Ef crawlspace access doors do not remain secured, standing water also presents a drowning hazard.
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Access and ventilation openings shall be provided to the crawlspace area according to the local
building codes and regulations. Access and ventilation requirements under the IRC 2000 include the
following:
allow access to mechanical equipment or building utilities located in this space.
• The minimum net area of required ventilation openings shall not be less than 1 square foot for each
150 square feet of enclosed crawlspace area. One such ventilation opening shall be within 3 feet of
each comer of the building. Ventilation openings shall be covered with an appropriate material.
f MIT 11019
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Ordering Information
your area. In addition,'kchrucal Buletins and other V.irl V1,LTumicanori =0 Tromilte
FEMA Publications Distribution Facility at 1-800-480-2520. The Technical Bulletins are also
available at the FEMA web site at www.j5:=xov.
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Further Information
WRWIF "INTO , " MR41 11 - - I . - PM1PV4#M_
Reinforced Concrete. Detroit, Aff.
American Society of Civil Engineers. 1998. SEVASCE 7-98. Mnimurn Design Loads for Buildings
and Other Structures. Reston, VA.
American Society of Civil Engineers. 1998. SEI/ASCE 24-98. Flood Resistant Design and
Construction. Reston, VA.
Federal Emergency Management Agency. 1986. F loodproofing Non-Residential Structures. FEMA
102. Washington, DC.
Federal Emergency Management Agency. 1•99. Protecting Building Utility Systems From Flood
Damage. FEMA 348. Washington, DC.
Flood-Prone Residential Structures. FEMA 259. Washington, DC.
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Requirements for Masonry Structures.
National Association of Home Builders Research Foundation, Inc. 1977. Manual for the Construction
of Residential Basements in Non-Coastal Flood Environs. Upper Marlboro, MD. March.
National Association of Home Builders Research Center, Inc. 2000. Residential Structural Design
Guide: 2000 Edition. Upper Marlboro, D.
Ease Flood — The flood that has a I -percent probability of being equaled or exceeded in any given
Vear (also referred to as the I 00-year flood).
Basement — Any area of a building having its floor subgrade (below ground level) on all sides.
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Community - Any state or area or political subdivision thereof, or any Indian tribe or authorized
WiN.0 f _&
iz 96ye wyanization, which has the authori
• adopt and enforce floodplain management regulations for the areas within its jurisdiction.
Federal Emergency Management Agency (FEMA) -'Me independent Federal agency that, in
addition to carrying out other activities, administers the NFER
Federa] insurance and Mitigation Administration (FIMA) - The component of FEMA direc
responsible for administering die flood hazard identification, floodplain management, and flood
insurance activities of the NFIR I
Flood Insurance Rate Map OFIRM) - The insurance and floodplain management map issued by
�mqgigiip
New construction/structure - For floodplain management purposes, new construction means
management regulation adopted by a community and includes subsequent improvements to the
structure. For flood insurance purposes, these structures are often referred to as "post-FIW'
Special Flood Hazard Area (SFUA) - Area subject to inundation by the base flood, designated Zol
A, Al-30, AE, AH, AO, V, VIN30, orVE.
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