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

Objective

 

 

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.

 

 

 

 

Region Office

Telephone

Region Office

Telephone

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

 

 

 

 

 

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 .

 


Obtaining a Building Permit

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

 

 

Marine plywood

The most water-resistant plywood; it can be used for floor and exterior-wall sheathing.

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.

 

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.)

 

 

 

 

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

Mitigation Steps You Can Take

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.


Relocating Your House

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.

Elevating Your House

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

 


House Elevation Regulations

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).

Elevating a Mobile Home

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.

 


Suspending a Heating System

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.

Elevating a Washer and Dryer

 

 

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.


Relocating a Washer and Dryer

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


Anchoring a Fuel Tank

 

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.

 

Sealing Openings In Walls

 

 

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 Pumps

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.

Installing a Backflow Valve

 

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.


Installing a Floor Drain Plug

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