Lowest Floor Elevation
Home Builder’s Guide to Coastal Construction
FEMA 499/August 2005
Technical Fact Sheet No. 4

Purpose: To discuss benefits of exceeding the National Flood Insurance Program 
(NFIP) minimum elevation requirements, to point out common construction 
practices that are violations of NFIP regulations and result in significantly 
higher flood insurance premiums, and to discuss the NFIP Elevation Certificate. 

Why Is the Lowest Floor Elevation Important?
In inland areas, experience has shown that floods damage areas of buildings not 
elevated above the flood level and destroy contents of those areas. In coastal 
areas, wave action causes even more damage, often destroying enclosed building 
areas below the flood level (and any building areas above the flood level that 
depend on the lower area for structural support). Once waves rise above the 
lowest structural member in a V zone or coastal A zone, the elevated portion of 
the building is likely to be severely damaged or destroyed.

Recommended Lowest Floor Elevations*
Because of the additional hazard associated with wave action in V zones and in A 
zones in coastal areas, it is recommended that the minimum elevation requirements 
of the NFIP be exceeded in these areas:
--It is recommended that the bottom of the lowest horizontal structural member 
of V-zone buildings be elevated 1 foot or more above the Base Flood Elevation 
(BFE), i.e., add freeboard. 
--It is recommended that the lowest horizontal structural member of A-zone 
buildings in coastal areas be elevated 1 foot or more above the BFE (i.e., add 
freeboard).

Note: NFIP minimum elevation requirements: A zone – elevate top of lowest floor 
to or above BFE; V zone – elevate bottom of lowest horizontal structural member 
to or above BFE. In both V and A zones, many people have decided to elevate a 
full story for below-building parking, far exceeding the elevation requirement. 
See Fact Sheet No. 2 for more information about NFIP minimum requirements in A 
and V zones.

What Does FEMA Consider the Lowest Floor?
--The “lowest floor” means the lowest floor of the lowest enclosed area, except 
for unfinished or flood-resistant enclosures used solely for parking of 
vehicles, building access, or storage.
--If the lowest enclosed area is used for anything other than parking of 
vehicles, building access, or storage, the floor of that area is considered the 
lowest floor. This will violate NFIP requirements and drastically increase flood 
insurance premiums.
--Note that any below-BFE finished areas, including foyers, will violate NFIP 
requirements, sustain unreimbursable flood damage, and increase flood insurance 
premiums. 
--The floor of a basement (where “basement” means the floor is below grade on 
all sides) will always be the lowest floor, regardless of how the space is used.
--Walls of enclosed areas below the BFE must meet special requirements in 
coastal areas (see Fact Sheet No. 27). 

Construction Practices and the Lowest Floor
Setting the lowest floor at the correct elevation is critical. Failure to do so 
can result in a building being constructed below the BFE. As a result, work can 
be stopped, certificates of occupancy can be withheld, and correcting the 
problem can be expensive and time-consuming.
--After piles have been installed, the intended elevation of the lowest floor 
should be checked before the piles are cut off.
--Alternatively, after piers or columns have been constructed, the intended 
elevation of the lowest floor should be checked before the lowest horizontal 
structural supporting members are installed.
--After the lowest horizontal structural supporting members have been installed, 
the elevation should be checked again, before any further vertical construction 
is carried out.

Do not modify building plans to create habitable space below the intended lowest 
floor. Doing so will put the building in violation of flood regulations and 
building codes.

FEMA Elevation Certificate
The NFIP requires participating communities to adopt a floodplain management 
ordinance that specifies minimum requirements for reducing flood losses. One 
such requirement is that communities obtain, and maintain a record of, the 
lowest floor elevations for all new and substantially improved buildings. The 
Elevation Certificate (see following pages) provides a way for a community to 
comply with this requirement and for insurers to determine flood insurance 
premiums.

Most communities require permit applicants to retain a surveyor, engineer, or 
architect to complete and submit the elevation certificate. Note that multiple 
elevation certificates may need to be submitted for the same building: a 
certificate may be required when the lowest floor level is set (and before 
additional vertical construction is carried out); a certificate will be required 
upon completion of all construction.

The Elevation Certificate requires that the following information be certified 
and signed by the surveyor/engineer/architect and signed by the building owner:
--elevations of certain floors in the building
--lowest elevation of utility equipment/machinery
--floor slab elevation for attached garage
--adjacent grade elevations
--flood opening information (A zones)

The Elevation Certificate is available on FEMA’s web site: 
http://www.fema.gov/nfip/elvinst.shtm
[two pages of the elevation certificate are attached]

[End of Fact Sheet No. 4]