Protecting Your Home
From Flood Damage
Mitigation Ideas
For Reducing Flood Loss
FEMA
Federal Emergency Management Agency
Table of Contents
Objective ........................................................................................................................................................................... i
The National Flood Insurance Program
(NFIP) and Building in the Floodplain .............................................................. 1
Flood Insurance A Good
Investment ............................................................................................................................. 2
Obtaining a Building
Permit ............................................................................................................................................. 3
Selecting a Contractor...................................................................................................................................................... 4
Tips for Repairing a
Flood-Damaged House .................................................................................................................. 5
Water-Resistant
Building Materials ................................................................................................................................. 6
Mitigation Steps You Can
Take ...................................................................................................................................... 7
Relocating Your House
................................................................................................................................................... 8
Elevating Your House
..................................................................................................................................................... 9
Elevating a Structure with
Crawlspace Foundation ....................................................................................................... 10
Elevating a Slab-on Grade
Wood Frame Structure ..................................................................................................... 11
House Elevation
Regulations ........................................................................................................................................ 12
Elevating a Mobile Home
............................................................................................................................................. 13
Elevating an Electrical
System ..................................................................................................................................... 14
Elevating Electric
Baseboard Heaters .......................................................................................................................... 15
Elevating or Relocating
the Electric Panel..................................................................................................................... 16
Elevating or Relocating
the Heating Plant ...................................................................................................................... 17
Suspending a Heating
System ..................................................................................................................................... 18
Elevating a Washer and
Dryer ..................................................................................................................................... 19
Relocating a Washer and
Dryer ................................................................................................................................... 20
Elevating or Relocating a
Water Heater......................................................................................................................... 21
Elevating an Air
Conditioning Compressor or Heat Pump ........................................................................................... 22
Anchoring a Fuel Tank
................................................................................................................................................. 23
Improving Interior Wall
Construction ............................................................................................................................. 24
Pumping Out a Flooded
Basement .............................................................................................................................. 25
Sealing Openings In Walls
........................................................................................................................................... 26
Installing
an Exterior Floodwall ...................................................................................................................................... 27
Installing
an Interior Floodwall ....................................................................................................................................... 28
Installing an Exterior
Foundation Drainage System ...................................................................................................... 29
Installing an Interior
Foundation Drainage System ....................................................................................................... 30
Sump Pumps ............................................................................................................................................................... 31
Installing a Backflow
Valve ............................................................................................................................................ 32
Installing a Floor Drain
Plug .......................................................................................................................................... 33
Index of Publications
................................................................................................................................................ 34-36
This
manual was developed to provide a broad range of information about flood
insurance, flood resistant construction techniques and water-resistant building
materials. It includes illustrations depicting floodproofing methods from
relocation and elevation to other less expensive alternatives.
If your home is
flood-prone or flood-damaged, you owe it to yourself to be as knowledgeable as
possible. If you choose to investigate some of these options or have any
questions, call the Federal Emergency Management Agency (FEMA) Mitigation
Office for your region at the number listed below.
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Region Office |
Telephone |
Region Office |
Telephone |
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1 |
617/223-9561 |
VI |
817/898-5127 |
|
1I |
212/225-7200 |
VII |
816/235-7002 |
|
III |
215/931-5502 |
VIII |
303/235-7830 |
|
IV |
770/220-5400 |
IX |
415/923-7177 |
|
V |
312/408-5548 |
X |
206/487-4678 |
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An index of publications is on pages 33-35. To
order publications call 1-800-480-2520.
Protecting
Your Home from Flood Damage, Revised 1997, 3rd Edition. Federal Emergency Management
Agency.
The National Flood Insurance Program and Building in the
Floodplain
What is the National
Flood Insurance Program?
The National Flood Insurance Program (NFIP) is a federal program enabling property owners and renters to purchase flood insurance. It is based on an agreement between your community and the federal government. The agreement states that if your community adopts and enforces floodplain management regulations which at least meet minimum federal requirements, the federal government will make flood insurance available in your community.
How do I know if I'm in
the floodplain?
The
floodplain is identified as a Special Flood Hazard Areas (SFHA) in your
community's Flood Insurance Study and the accompanying Flood Insurance Rate
Maps (FIRMs) published by FEMA. Your community's building officials or
floodplain
administrators
have these documents available for you to see. The flood level shown for these
SFHA has a 1 % chance of being equaled or exceeded in any one year. That
translates into a 26% chance of flooding over a typical 30-year mortgage period
as compared to a 1 % chance of fire damage over the same period.
What is substantial
damage?
Substantial
damage is damage of any origin to a structure where the cost of restoring the
structure to its before damage condition would equal or exceed fifty percent
(50%) percent of its pre-disaster value.
When does it affect me?
The
NFIP requires participating communities to regulate through building permits
any new or substantially improved structures during non-disaster periods and to
monitor and identify any substantially damaged structures as a result of a
disaster within the community's floodplain areas. Participating communities
adopt an ordinance requiring new buildings to be elevated at or above the Base
Flood Elevation (BFE) within the identified floodplain. Non-residential
buildings have the option of being dry flood proofed. Existing buildings that
are substantially damaged or improved (50% or more) must be elevated or
floodproofed to meet the same building code standard as a new building. When
you apply for a building permit, you will be informed whether or not you are in
a floodplain and what further steps are required to repair or reconstruct your
building if you are within this defined area. If your building was flooded but
not substantially damaged there is a wide range of inexpensive measures
described in this booklet that can help you reduce future flood damage.
How high will I have to
elevate?
Or floodproof?
The
elevation or floodproofing requirement is based upon the BFE as indicated in
the Flood Insurance Study of your community. This elevation may or may not be
comparable to the last major flood. Though you had ten feet of water in your
home during the last flood that may not mean you will need to elevate or
floodproof to that height. Your community's building official can assist you in
determining the elevation requirement for your structure.
What happens if I refuse
to comply?
Participating communities in the NFIP, agree to enforce its floodplain regulations. If you do not obtain a permit and do not elevate or floodproof when required, your community could take legal action against you. This may include stopping the development, revoking the permit, imposing a fine, or withholding a certificate of occupancy. If the structure is in violation of the regulations, flood insurance premiums could be extremely costly, possibly making the structure difficult to sell. Non-compliance could jeopardize your community's continued participation in the NFIP. Federally secured loans and federal disaster assistance are restricted in communities not participating in the NFIP that contain one or more SFHA which have been identified on a FIRM or Flood Hazard Boundary Map (FHBM) for at least one year prior to the disaster declaration. Additionally, structures located in the floodplain which are not elevated or floodproofed as required pose a threat to the health and safety of the occupants.
What if I have more
questions?
Your
building and floodplain management officials are responsible for implementing
the requirements of the local floodplain management ordinance, including the
substantial damage provisions. Following a disaster declaration, the
requirements pertaining to substantial damage will be presented to your
community officials in detail at meetings held in various locations in the
state. FEMA will work with building officials to help identify structures which
may qualify as substantially damaged. In addition, FEMA will provide technical
assistance to local building officials concerning the repair or reconstruction
of substantially damaged structures.
Flood Insurance-A
Good Investment
Flood
Insurance is a good investment for property owners and renters. A Flood
Insurance Policy:
·
Covers almost all flooding conditions.
·
Cannot be denied because of a structure's location
in a floodplain or its flood history. Will provide up to $500 to cover the cost
of moving your possessions to higher ground - including moving a mobile home.
·
Will cover replacement costs for primary
single-family residences with full coverage.
·
Will cover both structures and contents, if insured
for both.
·
Can pay a claim or partial claim within days of the
disaster even without a Presidential Disaster Declaration.
·
Premium can be reduced if appropriate mitigation
measures are taken.
·
Will pay to repair the flood-damaged part of your
building or contents in accordance with your policy terms and conditions.
·
Has a deductible, very much like other insurance
policies.
·
On policies effective June 1, 1997 and later, and
under specific conditions, will pay for additional costs for retrofitting to
meet LOCAL codes.
Flood
Insurance is available only to residents of communities participating in the
National Flood Insurance Program. (NFIP). For general information about flood
insurance and to learn if your community is participating in the NFIP, call
1-800-427-4661.
If items such as your furnace, water heater,
electrical fuse box, or other key elements were damaged consider using the
mitigation techniques in this book to reduce future flood damage. If undertaken
at the time you are repairing damage, or making some other major renovation to
your home, these retrofitting measures do not greatly increase the cost of
repairs
If there is a Presidential Declaration, other sources of funds may be available for mitigation. You may be eligible for a Minimal Home Repair grant, a Small Business Administration disaster loan, or Individual and Family Grant Program assistance. Ask those program officials about additional mitigation assistance to reduce future flood damage to the items they are helping to repair or replace. Information on these and many other funding sources is available at a Disaster Recovery Center (DRC). The location of the DRC in your area is available through the local news media-newspapers, radio and television-and through the Federal and State Community Relations personnel canvassing the disaster area.
Flooded? Here's what to do.
If you experience flood damage and are covered by flood insurance, these important steps will help you when filing your flood insurance claim.
1.
Save as many damaged articles as, possible. If
you must throw items out, take pictures to document your losses.
2. Contact your insurance
agent right away.
Once your insurance agent
has your claim:
Ř
The agent will file a Notice of Loss.
Ř
An adjuster will be assigned to your case.
Ř
Once the loss has been adjusted, a Proof of Loss
will be submitted, and payment can be made. Partial payment can be made to
claimants upon submission of a partial Proof of Loss .
Local
codes generally require a building permit before you repair or floodproof your
structure. Usually you need to get a permit for electrical work, plumbing and
repairs for structural damage, such as foundations and exterior walls. Because
your property may be located in a designated floodplain you will also
want to check with the permit department before constructing any floodwalls or
berms on your property. Your permit department will have maps called Flood
Insurance Rate Maps (FIRMs) that will show the floodplain in your community.
This area is known as the Special Flood Hazard Area (SFHA).
The
National Flood Insurance Program (NFIP), and most local and state building
codes require that a building in the floodplain that is substantially damaged
or substantially improved be treated as new construction. The lowest floor must
be elevated at or above the Base Flood Elevation (BFE). The BFE is also known
as the 100-year flood level. Substantial damage means that the cost to
restore your house to its "before damaged" condition would equal or
exceed fifty percent (50%) of the market value of your house before the damage
occurred. Substantial improvement means any reconstruction,
rehabilitation, addition, or other improvement of a structure, the cost of
which equals or exceeds fifty percent (50%) of the market value of the
structure before the start of construction of the improvement. Combining a
repair with an improvement where the total cost equals or exceeds fifty percent
(50%) of the market value of your house before the damage occurred will also
trigger the requirement to elevate.
If
your home is substantially damaged you may have no choice but to elevate or
relocate your house to meet NFIP standards. Some property owners have chosen
the option of relocating their house.
Failure to follow the local building code
can result in an order to stop construction, a fine, higher flood insurance
rates, denial of flood insurance, or all of the above.
Selecting a Contractor
Finding a good contractor
to handle difficult repair jobs or to rebuild is essential. Here are some tips
to help.
Sleuthing
If
you have been satisfied with work done before by a local licensed contractor,
use that firm. If you haven't used a contractor before, or if you were unhappy
with a previous experience, you may have to do some investigating to increase
your chances of getting a good one.
·
Ask the contractor for proof of insurance. This
should include a completion bond, disability and worker's compensation
insurance. Improperly insured contractors may expose you to liability for
accidents occurring on your property.
·
Check on the firm's reputation. Ask the local
Better Business Bureau, home builders association or building trades council.
They can tell you if the firm has had unanswered complaints filed against it.
·
Ask for references. Reputable contractors are
willing to provide names of their previous customers. Contact some of them and
ask how satisfied they were with the job and if they would hire that contractor
again.
Get it in writing
No
matter how well you know the contractor or how much you trust him/her, get
everything related to the job in writing.
·
Get a written estimate. It should include
everything you expect the contractor to do. Some contractors charge a fee for
an estimate.
·
Obtain a contract. The contract should be complete
and clearly state all the work, costs, and payment schedule. Never sign a blank
contract or one with blank spaces. It may be worthwhile to have your attorney
look it over if a lot of money is involved.
·
Ask for guarantees. Any guarantees from the
contractor should be written into the contract. It should include what is
guaranteed, who is responsible for the guarantee *(dealer, contractor,
manufacturer) and the length of time for which the guarantee is valid.
·
Get a final contract. A signed contract is binding
on both you and the contractor. Don't sign completion papers or make the final
payment until the work is finished to your satisfaction and approved by your
local building inspector.
Beware of Disreputable Business Activities
Areas
recovering from floods are often prime
targets for less-than-honest business
activities. Here are some points to help safeguard against such practices
Ř Beware
of "special deals" offered after a disaster by contractors you don't know.
Ř Beware
of unknown contractors wanting to use your house as a "model home."
Ř Do
not sign any contract under pressure by a salesperson. Federal law requires a three day
cooling-off period for unsolicited door-to-door sales of more than $25. If you
choose to cancel such a contract within three business days of signing it, send
your cancellation by registered mail.
Ř Beware if you are asked to pay
cash on the spot instead of a check made out to the contracting company. A reasonable
down payment is up to 30% of the total project cost.
Ř Your
contractor should call you or a qualified observer to inspect hidden work
(e.g., sewers or basement wall) before it is covered over. Most building
departments must inspect electrical and plumbing lines before the walls are
covered with wallboard or paneling.
Tips for Repairing a Flood Damaged Building
The most important thing -give your house
plenty of time to dry! Rushing to rebuild before everything dries
can cause many problems. The rule of thumb is, if it takes a week for visible
moisture to disappear, it will take at least another week for unseen parts to
dry. Here are some inexpensive measures you can take to make your recovery
easier after the next flood.
Utilities
Electrical: Move the main breaker or fuse box and utility meters at least 12" above the Base Flood Elevation (BFE) for your house. (BFE is also referred to as the 100 year flood level). Label each circuit. If the electrical code allows, raise the electrical outlets and switches above the flood level.
Equipment:
Relocate or elevate all equipment at
least 12" above the BFE. If
you plan to replace a flooded furnace, water heater, or air conditioner,
install the new one on a higher floor. If your new air conditioner or heat pump
will be outside, install it on a raised platform. An updraft furnace in a
basement can be replaced with a downdraft furnace on an upper floor. Place
heavy appliances on raised platforms. Make sure washers/ dryers will not
vibrate off the blocks or platform during use. A one or two foot waterproof
floodwall around appliances will protect them from shallow flooding.
Walls
Wash
and disinfect the studs and sills if the wallboard and insulation were removed.
If rebuilding, consider metal studs and sills as they are less damaged by water
than wooden ones. Pressure-treated wood resists mildew and wood-eating insects
but may swell when soaked. Warning: Some pressure-treated wood should not be
used inside the house. It depends on the chemicals used to treat them. Ask your
lumber company for consumer information that gives specific precautions.
Wallboard
If you install the wall board horizontally (four feet high), you'll only have to replace half the wall if the next flood is less than 4 feet deep.
Leave
the wall open 1 inch above the sill. The baseboards will hide the gap, but all
you have to do after the next flood is remove the baseboard and the wall cavity
will drain freely and air will circulate better. (Not applicable if local code
requires a fire wall.)
Greenboard
or other moisture-resistant wallboard may be more sturdy than regular
wallboard, but replacement is still often recommended as it presents the same
health hazards when soaked with floodwaters.
Floors
Particle
board or plywood fall apart when wet for lengthy periods. Floor joists and some
wood floors regain their shape when naturally dried. Use screws or screw nails
on floors and stairs to minimize warping. Completely dry subflooring before
laying new flooring or carpeting. Renail, then sand or place a new underlayment
for a new floor.
Paints
Completely
dry the surface before painting. This may take several weeks, but paint will
peel if applied over a damp surface. Coat concrete surfaces with penetrating
sealer for easier future cleanup. Coat water-stained areas with shellac or
commercial stain killer first or the stains will bleed through the paint. Dryproofing
requires thick plastic or rubberized sheeting. Waterproofing paints do not keep
out floodwaters.
Windows
and Doors
When
appropriate, replace flood damaged windows with vinyl or metal framed windows.
Hollow core or polystyrene foam filled metal doors are water resistant. Metal
in both windows and doors may rust slightly but that is easily repaired.
Water Resistant Products
Ř
Concrete, concrete block, or glazed brick
Ř
Clay, concrete, or ceramic tile
Ř
Galvanized or stainless steel nails, hurricane
clips, and connectors (in areas subject to saltwater flooding)*
Ř
Indoor-outdoor carpeting, synthetic backing (not
fastened down)
Ř
Vinyl, terrazzo, or rubber floor covering, with
waterproof adhesives
Ř
Metal doors and window frames, vinyl window frames
Ř
Polyester-epoxy paints (Warning: do not use
mildew-resistant paint indoors as it contains a toxic ingredient.)
Ř
Stone, slate, cast stone with waterproof mortar
Ř
Mastic, silicone, polyurethane formed-in-place
flooring
Ř
Polystyrene plastic foam insulation D
Water-resistant glue
*
See Technical Bulletin 8-96, Corrosion Protection for Metal Connectors in
Coastal Areas
Water-Resistant Building Materials
|
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Marine plywood |
The most
water-resistant plywood; it can be used for floor and exterior-wall
sheathing. |
|
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Exterior-grade plywood |
Meant to
resist low-level moisture, humidity. Not for water saturation conditions. |
|
|
Greenboard |
Manufacturers
do not consider greenboard (moisture-resistant dry wall) to be a
floodproofing material. It can be submerged for several hours without
extensive deterioration and it is only slightly more expensive than normal
plasterboard. |
|
|
Rigid (closed-cell) insulation |
Will not deform
or lose its insulative properties when wet. Can be dried out and
reinstalled in wall or floor cavity. Use instead of fiberglass insulation. |
|
|
Synthetic baseboards |
Use instead
of wood base. |
|
|
Galvanized nails |
Will
not rust after being in floodwaters.
Use at all locations up to three feet above the Base Flood Elevation. |
|
|
Metal doors and frames |
Will
not warp if saturated. May rust in spots, but this can be sanded out and
repainted. Use at all doorways, especially exterior. |
|
|
Metal and vinyl windows |
Will
not warp if saturated. |
|
|
Sheet vinyl flooring or tile |
Adheres
to marine or pressure treated plywood underlayment with waterproof adhesive. |
|
|
Indoor and outdoor carpet |
Use with
synthetic carpet pad. Do not permanently fasten down. |
|
|
Galvanized drywall screws |
Will
not rust and allow easy removal and reassembly of interior walls. Use instead
of standard drywall nails. |
|
|
Brick, concrete |
Not
damaged by water saturation, but must be used in conjunction with a
waterproof membrane. |
|
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Plastic wood |
Made
of recycled plastics. Waterproof and dimensionally stable. Check building
code for acceptable uses. |
|
|
Pressure-treated lumber/plywood |
Relatively stable
in water saturation conditions. Will not sustain heavy damage but may warp.
Plywood second only to marine plywood in water-resistance. Use at all
flood-levels. Moisture-resistant material below the Base Flood Elevation.
(Note: If treated lumber is used, protective gloves must be worn during
installation, and a protective barrier such as drywall must be placed between
the treated lumber and living space.) |
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Building Materials to Avoid When Floodproofing
Fiberglass or cellulose installation
Cork or corkboard
Gasoline, motor oil, weed killer, pesticide,
lye, drain dear, swimming pool and other chemicals
Linoleum
Particle
board, plywood, chipboard, fiberboard, paperboard, strawboard, Masonite paneling
Wallboard,
plasterboard, drywall, gypsum
Wallpaper
There
is a wide range of flood protection measures for buildings that can eliminate
or reduce the risk of future flood damage. Buildings can be relocated out of
the floodplain area or elevated above the projected flood levels. There are also
a number of relatively inexpensive flood mitigation techniques that can be used
to protect specific elements of a building. This booklet provides illustrations
of many flood loss reduction techniques and highlights some important basic
building code requirements for building or repairing homes located in a
floodplain.
√ Relocate
√ EIevate
√ Other Options
Please note: Throughout this booklet you will see the terms Base Flood Elevation (BFE) and 100-Year Flood Level. These terms are interchangeable. Base Flood Elevation is the term used in most NFIP and Floodplain Management documents. The 100-year Flood Level may be more commonly known.
It
is possible, and sometimes necessary, to move your house to a new location
outside the floodplain. Moving your home out of the floodplain area is the
surest way to protect it and yourself from flood damage, but it can be costly.
You may need to purchase a new lot unless your present lot is large and has a
good building location on higher ground.
To relocate a building, it is detached from the
original foundation, placed on a heavy-duty truck bed, transported to the new
site and set on a conventional foundation.
Unless
there is a hidden structural defect, most homes and small commercial buildings
in good structural condition can be moved with no more damage than occasional
slight cracks in the plaster or wallboard joints. Single-story frame houses
over a crawlspace or basement are easiest to relocate. Multi-story,
slab-on-grade, and brick buildings can also be moved.
Moving
a house is a complex operation that requires a professional house mover. Before
you choose a house mover, obtain bids from several companies and contractors.
Before choosing the lowest bid be certain
the contractor or mover has the experience and resources to complete the
project at the quoted price. Be certain that they have liability insurance to
cover the move.
Construction Steps
Involvedin Building Relocation
·
Locate a new building site.
·
Check the transportation route
to the new location. Is it adequate to move the house?
·
On the building site, construct
a new perimeter and interior foundation to fit the existing house. Stub in new
utilities to as needed.
·
Disconnect, elevate and move the house to the new
location.
·
Lower and anchor, the building onto the new
foundation.
·
Connect the new utilities.
Most
types of homes, including wood frame, brick veneer, slab-on-grade, crawlspace
or homes with basements can be elevated above floodwaters. This is a reliable
floodproofing method and requires little human intervention to prepare for a
flood. Elevation requirements vary with local codes and ordinances but the new
first floor elevation should be at or above the 100-year-flood level. You may
wish to exceed the code requirements. Some buildings may be elevated high
enough for the new lower level to serve as a garage. All elevated homes need
new stairs and porches built to the new height. Elevating a home requires the
services of plumbers, electricians, house movers and contractors. Because the
new foundation will be in the floodwaters, it is important that it be
structurally designed to withstand lateral (sideways) forces like fast-flowing
currents and the impact of waterborne debris. A structural engineer can help
you design your new foundation and obtain a permit from your building department.
Basic Steps in Elevating a
Building:
·
Have appropriate professionals disconnect
all utilities.
·
Hire a professional house mover to disconnect your house
from the existing foundation, jack it up to the new height and provide
a temporary foundation.
·
Have the utilities temporarily reconnected so the
house is liveable while foundation work is done.
·
Build a temporary access stair to meet the new
height.
·
Build a new, permanent foundation.
·
Have the house mover lower the house onto the new
foundation and connect them together with anchor bolts.
·
Have the utilities permanently reconnected.
·
Build a new, permanent access stair and landing
Elevating a Structure with Crawlspace Foundation
Elevating a Slab-on-Grade Wood Frame Structure
Substantial Damage
Substantial damage is
structure damage from any cause where the cost of restoring the structure to
its "before damage" condition would equal or exceed fifty (50)
percent of its pre-disaster value.
NFIP Housing Elevation Regulations
Within communities
participating in the NFIP, certain requirements apply when building a new home,
when substantial damage has occurred to an existing home, or when substantial
improvements to an existing home are planned.
·
In A-Zones, the top of a building's lowest floor,
including basement, must be elevated to the Base Flood Elevation (BFE) plus any
additional height above the BFE your community may require.
A Zones -
Riverine and coastal areas subject to flooding with waves less than 3 feet in height.
·
In V-Zones, the lowest portion of the horizontal
structural members supporting the lowest floor must be elevated to the BFE plus
any additional height above the BFE your community may require.
V-Zones - Areas adjacent to the beach subject to unusually high
tides with wind driven, velocity waves of three ft. or more.
·
Building materials located below the BFE, must be
resistant to flood damage.
·
Any enclosed area below the BFE must be constructed
to prevent flotation, collapse, and lateral (sideways) movement of the
structure. In A-Zones, exterior walls must have sufficient openings, or be
designed, to allow the equalization of the hydrostatic forces on the walls. For
V-Zones only, the walls of the enclosed area must be constructed to breakaway.
Solid breakaway walls are not an integral part of the structural support of a
building and are intended through their design and construction to collapse
under specific lateral loading forces, without causing damage to the elevated
portion of the building or supporting foundation. An area so enclosed is not
secure against forcible entry.
·
Construction of basements (enclosures with floor
levels completely below ground level) is not permitted below the BFE.
·
All machinery and equipment servicing the building
must be elevated to or above the BFE or designed to prevent water from entering
or accumulating during flooding. Such machinery/equipment includes but is not
limited to furnaces, heat pumps, hot water heaters, air-conditioners, washers,
dryers, refrigerators and similar appliances, elevator lift machinery, and
electrical junction and circuit breaker boxes.
·
All space designed for human habitation, including
bedrooms, bathrooms, kitchen, dining, living, family and recreation rooms, must
be elevated to or above the BFE.
·
Uses permitted in spaces below the BFE are
restricted to vehicular parking, limited storage, and building access (stairs,
stairwells and elevator shafts).
Foundations, cross bracing and tiedowns are the three basics of
the proper elevation and anchoring of a manufactured home. Each is essential
for a safe and secure mobile home installation.
Foundations
A poured concrete footing, reinforced with rebar, gives maximum stability. Extend rebar from the footing and up into the steel reinforce concrete or concrete block pier. Solidly fill each concrete block with concrete. Cast threaded anchor bolts into the top of each pier to anchor the mobile home frame to the foundation. Posts attached to piers with special connectors cast into the concrete are also effective. In areas with soft ground, post foundations may be able to achieve the required foundation strength. Drive posts into the ground down to a rock foundation, or to a depth specified by an engineer. Backfill posts with concrete for maximum strength.
Cross-bracing
Diagonal bracing reduces foundation twisting and the potential
of collapse in flooding or high winds. Brace foundation posts with 2-inch
nominal lumber bolted to the piers, or with steel rods fitted through drilled holes,
fastened with nuts and tightened with turnbuckles.
Tie-down straps
Tie-down straps are used at the base of the manufactured home
and can be tied over the top. The most common failure is pullout of the ground
anchor. For maximum pullout resistance, cast the anchor into a concrete
deadman.
Note: In order for
manufactured/mobile home owners located in Special Flood Hazard Areas to be eligible
for NFIP flood insurance,
their manufactured/mobile home
must be able to resist
floatation, collapse or lateral movement either by: 1.) Over the top or frame ties to ground anchors; 2.) or in accordance with
the manufacturer's specifications;
3.) or in compliance with the
community's flood plain management requirements unless it is a
manufactured/mobile home on a permanent
foundation continuously insured by the NFIP on the same site since 9/30/82.
(Source: NFIP Standard Flood Insurance Policy, Article 6, Paragraph H)
Elevating an Electrical System
The
surest way to protect your valuable electrical system is to keep it from
getting wet. When rebuilding after a flood, or repairing by wet floodproofing,
move all wiring at least one foot above the 100-year flood level. All outlets,
switches, light sockets and junction boxes, as well as the main breaker or fuse
box and electric motors, should be out of danger of getting wet.
Run
wires overhead. If a wire has to run into the areas that could get wet use a
wire rated for underground use. No wire should end in the flood zone and all
junctions should be in approved junction boxes. If a wire has to terminate
below the 100-year flood level it should be specially marked in the panel box
and turned off at the time of a flood warning.
Change all outlets to
ground fault interrupters (GFI). Be sure all electrical wiring is done by a
licensed electrician and approved by the local building department.
Elevating Electric Baseboard Heaters
Protect your electric
baseboard heater system by elevating it at least one foot above the 100-year
flood level. Use waterproof wall construction materials and techniques for the
wall area below the baseboard units.
Elevating
or Relocating the Electric Panel
Elevate
or relocate your electric panel above the 100-year flood level to help prevent
damage. All relevant permits must be obtained before work begins, and all work
must conform to state and local building codes.
Elevate
Relocate electric
panel to a recommended minimum 12" safety margin above the base flood
elevation or the highest known flood level if you are outside of any known
flood zone. The maximum panel height is regulated by code.
Relocate
Relocate the electric panel to available space
above the first floor to protect it from flooding.
Certain repairs are not
permitted for substantially damaged buildings. Check with your local building
official or floodplain administrator before beginning repairs.
Elevating
or Relocating the Heating Plant
When
relocating or raising the heating plant be sure it will have a 12 inch safety
margin above the 100-year flood level. If the existing ductwork for your
furnace is below the 100-year flood level (e.g. inside a slab or crawlspace
beneath the home) it should be relocated so that it distributes heat from at
least one foot above the 100-year flood level. Your local building department can
help you determine your 100-year flood level. If you locate the furnace on an
upper floor or attic it will require the installation of a
"downdraft" furnace, which is slightly different from a standard
model. If you are replacing your furnace ask your supplier for information on a
downdraft system.
Certain repairs are not permitted
for
substantially damaged buildings. Check with your local building official or floodplain
administrator before beginning repairs.
Certain repairs are not permitted for substantially damaged
buildings. Check with your local building official or floodplain administrator
before beginning repairs.
Suspend the
heating system with a safety margin of at least 12" above the 100-year
flood level and in a manner that conforms to the manufacturer's specifications
and all applicable state and local building codes.
Certain
repairs are not permitted for substantially damaged buildings. Check with your
local building official or floodplain administrator before beginning repairs.
Elevate your washer and
dryer on a masonry or pressure treated lumber base to at least a 12"
safety margin above the 100-year flood level.
Certain repairs are not permitted for substantially damaged buildings. Check with your local building official or floodplain administrator
To protect them from flood damage, relocate washer and dryer to a floor at least 12 inches above the base flood elevation.
Elevating or Relocating a Water Heater
When relocating or
raising the water heater be sure that it will be at least 12 inches above the
100-year flood level. Consult your local building department for details.
Elevating an Air Conditioning Compressor
or Heat Pump
Unanchored fuel
tanks can tip over or float. Escaping fuel may result in spills and fires. To
prevent this, anchor your fuel tank. Use non-corrosive metal structural
supports and fasteners. The type of
anchorage, including slab dimensions, will vary depending on the size of the
tank. Keep the fuel tank topped off to increase the tank's weight and to
reduce it's tendency to float.
Note:
·
Check with the fuel
tank manufacturer for recommendations on anchoring.
·
Be sure all work
done conforms to state and local building codes.
·
For rented tanks,
check with the fuel supplier before making any modifications to the tank.
Improving Interior Wall Construction
Pumping Out a Flooded Basement
If your basement is flooded, don't rush
to pump it out.
Water in the
ground outside your house is pushing hard against the outside of your basement
walls; and the water inside your basement is pushing right back. If you drain
your basement faster than the water outside drains out of the ground, the
outside pressure will be greater than the inside pressure. This unequal
pressure may cause the floor to crack then buckle and the wall to crack and
possibly collapse.
How to Safely
Pump Water
Out of Your Basement
·
Never go into a flooded basement unless you are
sure the electricity is off.
·
Start pumping the water out of the basement when
floodwaters no longer cover the ground.
·
Gasoline engines create deadly carbon monoxide
exhaust fumes. Don't use gasoline-powered pumps or generators indoors.
·
Pump the water level down 2 to 3 feet. Mark the
level, and wait overnight.
·
Check the water level the next day. If the water
level went back up over your mark, it is still too early to drain your
basement. Wait 24 hours, then pump the water down 2 to 3 feet again. Mark the
level and check it the next day.
·
When the water stops rising, pump down another 2 to
3 feet and wait overnight. Repeat steps 4 and 5 until all water is pumped out
of the basement.
What to Do After Draining Your
Basement
·
Disinfect the floors and walls to remove bacteria
left from the floodwaters.
·
Before turning the power back on, check any
electrical service that may have been damaged. Replace any wiring, switches,
outlets that were wet during the flood.
·
Remove heating and air conditioning vents or
registers as soon as possible and hose out the ductwork. Flooded ducts contain
mud and bacteria.
·
Check your water system for loose pipes and leaks.
·
Check your water supply to be certain it is not
contaminated. Check all other utilities and drains for damage from the
floodwaters.
If your house is being flooded by flowing
waters entering through windows, doors or other openings, you can temporarily
seal those openings to keep the water out.
Make or purchase metal or wooden shields to
fit the openings. Secure the shields to the openings with bolts or slide them
into special positioning channels. Seal the shields to the opening with a
special rubber gasket or a bead of caulking to make them water tight. Also,
sandbags can be stacked in doorways or window wells and vents to make the
openings water resistant.
Note: Shield height generally should not exceed
11/2 feet above ground level.
Exterior water
deeper than 11/2 feet could push' the walls In if there is no water inside to
push back with equal force.
Installing an Exterior Floodwall
An exterior
floodwall can protect a window well or stair against low level flooding.
Constructed of concrete or masonry the walls should be supported by and
securely tied into a footing so they will not be undercut by scouring.
Understanding your particular flood situation and soil conditions is important
in order to properly evaluate if a flood wall is the right solution for you.
Floodwalls are not effective when the ground becomes saturated.
Construct a
watertight flood wall around the perimeter of the opening. The wall should not
exceed three feet in height and must be constructed of steel reinforced poured
concrete or steel reinforced concrete masonry units to prevent failure under
flood conditions. Install a proper footing and anchor the floodwall to existing
walls. Install a watertight, spring-loaded steel access door and watertight
gaskets on sides and bottom of frame at any necessary opening. Be sure all work
conforms to State and local building codes.
Installing an Interior Floodwall
An interior flood
wall can protect against low level flooding. The wall must enclose the
utilities and be at least one foot above the 100 year flood elevation. To
resist the pressure of the floodwaters, construct the wall of either steel
reinforced concrete blocks or steel reinforced poured concrete. Connect the new
wall to the existing basement wall and floor with properly embedded reinforcing
steel. For best protection, do not install gates which open into the
enclosure.
Installing an Exterior Foundation Drainage System
All
houses need a well-developed drain system to collect and carry away
groundwaters. This means installing drains around all footings. Use perforated
pipe surrounded by a filter fabric and covered with rounded drain rock to drain
water that seeps through the ground. These drains should slope to a low point
from which a single line should carry the water away from the house, either to
a drain line in the street or to a drywell on your property. Do not drain water
toward a hillside. Doing so may create concentrations of water that can trigger
landslides.
A
4" deep bed of gravel under the lab should allow water to run to a central
collection pint where there is a sump pump with a continuous power source. If
you have a lot of water under the slab, you may need to install perforated pipe
drain lines to carry the water to the sump pump.
As with other retrofitting systems, a sealed
house will usually need a sewer backflow protection device.
Exterior
Foundation Drain System
Installing
an Interior Foundation Drainage System
Some
homes need a basement foundation drain system to collect and carry away
groundwater. This may involve cutting the floor slab, excavating a trench and
installing drains along the inside perimeter of all footings. These drains
should slope to a low point from which a single line can carry the water away
from the house, either to a drain line in the street or a drywell on your
property. Do not drain water toward a hillside. Doing so may create
concentrations of water that can trigger landslides.
The basement
drainage retrofit depicted below is a simple, generic system utilizing
perforated drain pipe, wrapped in filter fabric, and imbedded in rounded drain
rock. Other, more sophisticated systems, some of which are patented, are
available to correct serious basement drainage problems. Consult an architect,
engineer or licensed specialty contractor for specific information and
recommendations regarding system alternatives.
Interior Basement Drain System
Sump:
A hole designed to collect water.
Sump Pump: A pump used to remove water from basements and other low areas.
A sump consists of
a perforated liner set in a hole lined with coarse stone. The stone helps
collect water and filter out fine particles. A filter cloth may extend the life
of the sump by preventing if from silting up. Perforated water-collection pipes
draining to the sump make it more effective. In some homes, all lower level
waste water is pumped up and out by a sump pump.
A
sump pump is usually either the submersible type with a motor and impeller
under water, or the pedestal type with the impeller under water and motor on
top. Both types have an automatic switch. Both types will work until the
electricity is shorted by the water. With the submersible type, this happens at
the end of the electrical supply wire. With the pedestal type, it happens when
the water reaches the motor on top of the pedestal. Both types should have a
one-way valve that will not allow the water to flow back into the discharge
hose or pipe.
Caution!
Electricity and
water are a hazardous combination. The sump pump must be wired into a grounded
receptacle that only allows one plug. A second nearby outlet should be equipped
with a ground fault circuit interrupter (GFCI). This second outlet should be
handy so that people working near the sump pump will not be tempted to unplug
it to use the outlet, thereby placing themselves in danger.
If
you drain your basement too quickly, the pressure outside the walls will be
greater than the pressure inside the walls and that may make the walls and
floor crack and collapse, causing serious damage.
To
avoid this situation, follow these steps when you pump the water out of your
basement: Never go into a flooded basement unless you are sure the electricity
is off.
Start
pumping the water out of the basement when floodwaters no longer cover the
ground. Gasoline engines create deadly carbon monoxide exhaust fumes. Don't use
gasoline-powered pumps or generators indoors.
Pump
the water level down 2 to 3 feet. Mark the level and wait overnight. Check the
water level the next day. If the water went back up (it covered your mark), it
is still too early to drain your basement. Wait 24 hours. Then pump the water
down 2 or 3 feet again. Check the level the next day.
When the water stops
going back up, pump down another 2 to 3 feet and wait overnight. Repeat steps 4
and 5 until all water is pumped out of the basement.
Note: Removal of
water from a basement where there is flooding or high
groundwater may cause the basement walls
to
collapse. Basements should not
be pumped out until the
floodwaters subside.
The sewage/septic
system is designed to remove sewage from a house. If flood water enters the
system, the sewage can backup and enter your home. To help prevent this,
install a backflow valve in the sewer line. The backflow valve is opened by the
flow of sewage exiting your home, but closes when the flow reverses preventing
sewage from backing up into your home. Check with your local building official
for permitting and code requirements. It is recommended that this work be done
by a qualified, licensed contractor.
Certain repairs are not
permitted for substantially damaged buildings. Check with your local building official or
floodplain administrator before beginning repairs.
The easiest way to stop sewer
backup is to plug the opening where the backup can first enter the house. The
sanitary system's lowest opening in the house is the floor drain. Commercial
plugs are available that can be placed in the floor drain below the grate.
Bolts on metal end pieces are tightened, causing a rubber gasket to expand and
seal the plug in the pipe.
A plug not only stops water from entering
the house but it prevents it from leaving the house as well. Because of this,
it may be best to put the plug in place only during heavy rains.
You may install a plug with a float. The
float allows water to drain out of the basement. When the sewer backs up, the
float rises and plugs the drain. A float plug permanently installed will not
interfere with the floor drain's normal operation.
Caution
·
Float plugs
may be blocked open by even small amounts of debris.
·
Floor drain
plugs do not stop backup from coming out of the next lowest opening, for
example a laundry tub or basement toilet.
·
In older
houses the sewer lines under the basement floor may be clay tile. A build up of
water pressure can damage the sewer lines.
Certain repairs are not permitted
for substantially damaged buildings. Check with your local building official or
floodplain administrator before beginning repairs.
Federal
Emergency Management Agency
Flood Program
Publications and Videos
|
|
|
|
|
Item # |
Publication |
|
|
3-0107 |
FEMA-1 5 |
Design Guidelines for Flood Damage
Reduction General
information on flooding and how to properly design and build in flood-prone
areas. |
|
8-0390 |
FEMA-54 |
Elevated Residential Structures Proper design and
construction methods for elevated buildings. |
|
8-0373 |
FEMA-55 |
Coastal Construction Manual Design and
construction techniques for construction in coastal high hazard areas. |
|
8-0497 |
FEMA-85 |
Manufactured Home Installation in Flood
Hazard Areas How to properly
install a manufactured home in a flood hazard area with emphasis on design of
elevated foundations. |
|
3-0125 |
FEMA-1 00 |
Unified National Program for Floodplain
Management A conceptual
framework to guide local, State, and Federal decision makers toward a balanced
consideration of alternative goals, loss reduction strategies, and tools.
(See FEMA-248 for an
update to this publication.) |
|
3-01326 |
FEMA-102 |
Floodproofing Non-Residential Structures Describes a
variety of floodproofing strategies for commercial and industrial structures. |
|
3-0127 |
FEMA-1 14 |
Design Manual for Retrofitting Flood-prone
Residential Structures Presents
floodproofing techniques that can be used for existing residential
structures. |
|
3-0131 |
FEMA-116 |
Reducing Losses in High Risk Flood Hazard
Areas: A Guidebook for Local Officials A guidebook to
help local governments improve their floodplain management programs for high
risk flood areas. |
|
3-0142 |
FEMA-165 |
Alluvial Fans Hazards and Management A booklet
describing flood hazards on alluvial fens and suggested approaches to hazard
management. |
|
3-0164 |
FEMA-213 |
Answers to Questions about Substantially
Damaged Buildings Guidance on NFIP
regulations governing substantially damaged structures. |
|
3-0178 |
FEMA-234 |
Repairing Your Flooded Home Repair manual for
homeowners on how to repair your home after a flood. |
|
|
FEMA-248 |
A Unified National Program for Floodplain
Management Updates the
information in FEMA-100. |
|
|
FEMA-257 |
Mitigation of Flood and Erosion Damage to
Residential Buildings in Coastal Areas Profiles
floodproof retrofitting in coastal states and communities. |
|
|
|
|
|
Item # |
Publication |
|
|
|
FEMA-258 |
Guide to Flood Maps A How-To booklet
for reading Flood Insurance Rate Maps (FIRMS). |
|
|
FEMA-259 |
Engineering Principles and Practices for
Retrofitting Floodprone Residential Buildings A comprehensive
technical manual with specific guidance on financial, engineering determination of
methods, and design practices for many floodproof retrofitting techniques. |
|
3-0180 |
FIA-22 |
Building Performance: Hurricane Andrew in
Florida Recommendations,
observations, solutions to building problems incurred during Hurricane
Andrew. |
|
3-0181 |
FIA-23 |
Building Performance: Hurricane Iniki in
Hawaii Recommendations,
observations, solutions to building problems incurred during Hurricane Iniki. |
|
3-0183 |
FIA-TB-0 |
Technical Bulletins: User's Guide with Key
Word and Subject Index Provides a list
of available technical bulletins, a key word-subject reference index for all
the bulletins, and information about how to obtain copies of the bulletins. |
|
3-0184 |
FIA-TB-1 |
Technical Bulletin 1: Openings in
Foundation Walls Guidance on the
NFIP regulations concerning the requirement for openings below the Base Flood
Elevation foundation walls for building located in Zones A, AE, A1-A30, AR,
A0, and AH. |
|
3-0185 |
FIA-TB-2 |
Technical Bulletin 2; Flood-Resistant
Materials Requirements Guidance on the
NFIP regulations concerning the required use of flood damage-resistant
construction materials for building components located below the Base Flood
Elevation in Special Flood Hazard Areas (both A and V Zones). |
|
3-0186 |
FIA-TB-3 |
Technical Bulletin 3: Non-Residential
Floodproofing - Requirements and Certification Guidance on the
NFIP regulations concerning watertight construction and the required
certification for floodproofed non-residential buildings in Zones A, AE, A1-A30,
AR, A0, and AH whose lowest floors are below the Base Flood Elevation. |
|
3-0187 |
FIA-TB-4 |
Technical Bulletin 4: Elevator
Installation Guidance on the
NFIP regulations concerning the installation of elevators below the Base
Flood Elevation in Special Flood Hazard Areas (both A and V Zones). |
|
3-0188 |
FIA-TB-5 |
Technical Bulletin 5: Free-Of-Obstruction
Requirements Guidance on the
NFIP regulations concerning obstructions to floodwaters below elevated
buildings and on building sites in coastal high Hazard Areas (Zones V, VE,
and V1-Y80). |
|
3-0189 |
FIA-TB-6 |
Technical Bulletin 6: Below-Grade Parking
Requirements Guidance on the
NFIP regulations concerning the design of below grade parking garages beneath
buildings located in Zones A, AE, A1 A80, AR, A0, and AH). |
|
3-0202 |
FIA-TB-7 |
Wet Floodproofing Requirements Guidance on the
NFIP regulation concerning the design of wet floodproofing which is not
recognized for residential homes, only for non residential structures. |
|
|
|
|
|
Item # |
Publication |
|
|
|
FIA-TB-8 |
Corrosion Protection for Metal Connectors
in Coastal Areas Guidance on the
NFIP regulation concerning the use of metal connectors in structures located
in coastal Special Flood Hazard Areas. |
|
3-0124 |
|
NFIP Regulations for Floodplain Management
and Flood Hazard Identification 44CFR Regulations
that pertains only to the-Floodplain Management Program. |
|
3-0132 |
L-153 |
Retrofitting Flood-Prone Residential
Structures (Brochure) A companion
brochure summarizing FEMA-114 |
|
3-0174 |
L-1
97 |
Unified National Program for Floodplain
Management Brochure A companion
brochure summarizing FEMA-100 |
|
3-0179 |
L-198 |
After a Flood: The First Steps (Brochure) A brochure that
pulls pertinent first step information from FEMA-234, |
|
3-0172 |
FF 81-78 |
Residential Basement Floodproofing
Certificate (7192) A form provided
to communities that have been granted a basement exception through FEMA
Headquarters. |
|
|
FF 81-31 |
Elevation Certificate A form provided
to communities participating in the NFIP for proper recording of elevated
buildings. |
|
|
FF 81-65 |
Floodproofing for Non-Residential
Structures A form provided
to communities participating in the NFIP for proper recording of
floodproofing non-residential buildings. |
|
|
Poster-15 |
Repairing Your Flooded Home
(English/Spanish) Poster for use in
public buildings with English on one side and Spanish on the other. |
|
Videos |
|
|
|
|
Best Build I |
Constructing a Sound Coastal Home |
|
|
Best Build II |
Construction in a Riverine Floodplain |
|
|
Best Build III |
Protecting a Flood-Prone Home |
To order publications,
contact: FEMA
Publications
P.O. Box 2012
Jessup, MD 20794-2012
1-800-480-2520