Property Protection

Flood protection can involve a variety of changes to your house and property – changes that can vary in complexity and cost.  Some changes you can do yourself.  But complicated or large changes and those that affect the structure of you house or its electrical wiring and plumbing should be done only by a professional contractor licensed to do the work.

The following are ways you can protect your property.

Deciding Which Method Is Right for Your Home

Your decision will be based primarily on legal requirements, the technical limitations of the methods, and cost.  Other considerations might include such things as the appearance of the house after retrofitting and any inconvenience resulting from retrofitting.  Making a decision involves four steps.  Click here for a Checklist

Determining the hazards to your home is generally based on historical information about your home or neighborhood.  Example; if you are not sure if your home has previously flooded, check with neighbors that have lived in the area for awhile.  They can provide information to events that have occurred.  Also, talk to the Office of Emergency Management, they generally will have records of disasters that have occurred in the community.  Additionally, if you recently bought your home and obtained a loan for the mortgage, the lender is required by law to notify you whether your home is in a Special Flood Hazard Area, and requires flood insurance.

If your home is in an area which is subject to one or more of these hazards, your retrofitting project should take the additional hazards into account.  Depending on the nature of the hazards and your choice of retrofitting methods, State and local regulations may require that additional changes be made to your house, beyond those necessary for flood protection.

Before you check with your local officials or consult a design professional and contractor, you should inspect your home, taking into consideration the characteristics mentioned above and the retrofitting project planned.

Construction Type

The construction type of most homes will be frame, masonry veneer, masonry, modular home, manufactured home, or a combination of two or more of these types.  The following generalizations can be made about the effect of construction type on retrofitting:

The most appropriate elevation technique for frame homes, and manufactured homes usually is to elevate on extended foundation walls or open foundations.

The most commonly used elevation technique for masonry homes usually is either (1) to extend the walls of the home upward and raise the lower floor or (2) abandon the lowest floor and move the living area to and upper floor.

Frame homes, masonry veneer homes, and manufactured homes are easier to relocate than masonry homes.

Masonry and masonry veneer homes are usually easier to dry floodproof than other types of homes, because masonry is a more flood-resistant material than the materials used in other types of homes.

Foundation Type

Most homes of the construction types mentioned above are built on a basement, crawlspace, slab-on-grade, or open foundation or on a combination of two or more of these types.  The following generalizations can be made about the effect of foundation type on retrofitting.

Slab-on-grad homes are more difficult to elevate than houses on basement or crawlspace foundations.

Elevating homes on basement foundations normally involves elevating or relocating utility system components usually found in basements, such as furnaces and hot water heaters.

Homes on basement foundations should not be dry floodproofed or protected by levees or floodwalls unless an engineering evaluation conducted by a design professional shows that it is safe to do so.  This precaution is necessary because neither dry Floodproofing nor the construction of levees or floodwalls prevents saturated soils from pressing on basement walls.  This pressure, which is unequalized because water is not allowed to enter the basement, can damage basement walls or even cause them to fail.

For some homes on basement foundations, the same type of engineering evaluation is a necessary part of a wet floodproofing project.  If the home is in an area where saturated soils begin to press on basement walls before water enters the basement, the unequalized pressure may damage walls or cause them to fail.  If wet Floodproofing is to be used in this situation, the engineering evaluation must show that the basement walls can resist the expected pressure.

Lowest Floor Elevation

The “lowest floor” of your home, as defined in the floodplain management section of the City Ordinance, is not necessarily the first or finished floor.  For example, the lowest floor could be the floor of a basement or the floor of an attached garage.  The location of your lowest floor can vary with foundation type.  For homes that are elevated, wet floodproofed, or dry floodproofed, the difference between the elevation of the lowest floor and the Flood Protection Elevation (FPE) determines how high the home must be elevated or how high the wet or dry floodproofing protection must reach.  In general, as the difference between the lowest floor elevation and the FPE increases, so does the cost of elevating, wet floodproofing, or dry floodproofing.  This difference is particularly significant for dry floodproofing.  Even masonry walls should not be dry floodproofed higher than 3 feet unless a structural evaluation by a design professional shows that it is safe to do so.

The elevation of your lowest floor can be established by a survey, which may be necessary as part of your retrofitting project.  But even if you do not know your lowest floor elevation, you can estimate the difference between it and the FPE.  If you haven’t yet decided on an FPE, don’t worry.  Your conversations with your local officials, contractors, and design professionals will help you determine the level of flood protection you should provide.

Remember, if your house has been substantially damaged or is being substantially improved according to the City Ordinance, your FPE must be at least equal to the Base Flood Elevation (BFE).

Condition

Your design professional or contractor should conduct a detailed inspection of your home before any retrofitting work.  You can help by first conducting your own assessment of the condition of your home and recording of any information you have about past or current damage.  This information may also be helpful to community officials who advise you about floodplain management and building code requirements and appropriate retrofitting methods.

If your home has been damaged by a flood, high-wind event, earthquake, fire, or other disaster, make note of the extent of damage, when it occurred, and whether it was repaired.  If repairs were made, make a note of who made them and describe what was done.  Any structural damage and repairs to walls, floors, foundations, and roofs is particularly important.  You should also describe any damage resulting from other causes, such as foundation settlement, dry rot, and termite damage.  Your goal is to give your design professional and contractor as much information as possible so that they can determine how the condition of your home will affect your choice of a retrofitting method.

Other Considerations

In addition to construction type, foundation type, and lowest floor elevation, you should make note of interior and exterior service equipment that must be protected as part of your retrofitting project.  Interior service equipment must be protected if you wet floodproof you home.  This equipment includes furnaces, heating and air conditioning ductwork, hot water heaters, large appliances, and electrical system components such as service panels, outlets, and switches.  Exterior service equipment must be protected if you elevate, wet floodproof, or dry floodproof and, in some situations, if you build a levee or floodwall.  This equipment includes air conditioning and heat pump compressors and electric and gas meters.

In a home that is dry floodproofed, all openings below the FPE must be sealed, including not only doors and windows but also the openings for water pipes, gas and electric lines, dryer vents, and sump pump discharge pipes.  In a home that is dry floodproofed, wet floodproofed, or protected by a levee or floodwall, backflow valves must be installed on all water and sewer lines with openings below the FPE.  These valves prevent flood waters and wastewater from backing up into your home.

This is a particularly important step.  The Planning Department and Office of Emergency Management have copies of the Flood Insurance Study (FIS) and Flood Insurance Rate Map (FIRM) published for the city by FEMA.  They will be able to tell you whether your home is in a regulatory floodplain and, if so, the BFE at the location of your home.  They may also have information about flood conditions near you home, including flow velocity, the potential for wave action and debris flow, rates of rise and fall, warning time, and duration of inundation.

The Planning Department will inform you of Federal, State, and local regulations, codes, and other requirements that can determine what retrofitting methods you will be allowed to use and how changes can be made to your home.  They can also tell you about Federal, State, and local programs that might provide financial assistance for homeowner retrofitting projects, and they can help you determine whether you are eligible for such assistance.

Remember that your goal is to find out what you can legally do to retrofit your home, identify the requirements you must comply with throughout the retrofitting process, and eliminate retrofitting methods that do not meet your needs.  You may find that the restrictions and requirements of Federal, State, and local regulations will eliminate some retrofitting methods from consideration.  Ultimately, your decision will be based on technical limitations of the methods, cost, and other considerations, such as the effect that retrofitting will have on the appearance of your home.

Your next step, whether you have chosen one method or are considering tow or more, is to consult a properly licensed, bonded, and insured design professional and retrofitting contractor.

You will probably need the services of a contractor regardless of the retrofitting method you select.  The type of contractor you hire will depend on the method you select.  You will probably also need to consult a design professional, such as a structural engineer.  Alternatively, you can hire a general contractor who will arrange for all the necessary services, including those of a design professional.  Knowing the types of services required for your retrofitting project is important, but so is making sure that your design professional and contractor are reputable and competent.

If you have used a licensed design professional and a licensed contractor in the past and were satisfied with the work, use them again.  Even if they do not provide the types of services you now need, they may be able to recommend someone who can.  Otherwise, you can check the Yellow Pages or call or write to the professional association that represents the types of specialists you are looking for.  Before you hire a design professional or a contractor, you should check with the Better Business Bureau, consumer protection agency, or licensing authorities.  These organizations can tell you whether there have been any complaints about the quality of the design professional’s or contractor’s past work, including whether the work was completed on time.

Next you will need to meet with the contractor and design professional to discuss your project.  At the meeting, be sure you do the following.

• Provide the information you collected in Steps 1, 2, and 3.
• Ask the questions listed on the checklist, as well as any others you may have.
• Verify that the contractor is licensed, bonded, and insured as a required by State law.
• Verify that the design professional is licensed and registered with the State.
• Ask for proof of insurance.  If the contractor or design professional does not have disability and worker’s compensation insurance, you may be liable for accidents that occur on your property.
• Ask for references.  Reputable contractors and design professionals should be willing to give you the names of previous customers.  Call some of them and ask how well they were satisfied with the work.  Ask if they would hire the contractor or design professional again.
• If you are trying to decide between two or more retrofitting methods, discuss your preferences and ask for more information.

Any contractor or design professional you hire will need to conduct a site visit to inspect your home and determine how the work should be carried out.  During the visit, you should expect your contractor or design professional to check the structural condition of your home and determine what changes will be required by the retrofitting method you choose.  If you agree on a method and decide to proceed with the project, be sure to do the following.

• Get a written, signed, and dated estimate.  It should cover everything you expect to be done.  (Some contractors and design professionals will charge a fee for this service).
• Decide whether you, the contractor, or the design professional will obtain the necessary permits.
• Ask for a warranty or guarantee.  Any warranty or guarantee from the contractor or design professional should be written into the contract.  The contract should clearly state the terms of the warranty or guarantee, who is responsible for honoring it (such as a manufacturer or the contractor), and how long it will remain valid.
• The written contract should be complete and clearly state all work to be done, the estimated cost, the payment schedule, and the expected start and completion dates for the work.

! Warning

Areas recovering from floods or other types of disasters are prime targets for less than honest business activities.  Here are some pointers that can help you avoid problems:

• Beware of “special deals” offered after a disaster by contractors you don’t know.
• Beware of unknown contractors who want to use your home as a “model home” for their work
• Do not sign any contract under pressure by a sales person.  Federal law requires a 3 day cooling off period for unsolicited door-to-door sales of more than $25.
• Beware if you are asked to pay cash on the spot instead of with a check made out to the business.
• Never sign a blank contract or one with blank spaces.  You may want to have your attorney check the contract if a large amount of money is involved.

Other Retrofitting Options

Sewer Backflow Valves

In some floodprone areas, flooding can cause sewage from sanitary sewer lines to back up into homes through drain pipes.  These backups not only cause damage that is difficult to repair but also create health hazards.

A good way to protect your home from sewage backups is to install backflow valves, which are designed to block drain pipes temporarily and prevent flow into the home.  Backflow valves are available in a variety of designs that range from the simple to the complex.  The figure below shows a gate valve, one of the more complex designs.  It provides a strong seal, but must be operated by hand.  So the effectiveness of a gate valve will depend on how much warning you have of impending flooding.  Among the simpler valves is a flap or check valves, which open to allow flow out of the home but close when the flow reverses.  These valves operate automatically but do not provide as strong a seal as a gate valve.

Keep these points in mind if you have a backflow valve installed:

• Changes to the plumbing in your home must be done by a licensed plumber or contractor, who will ensure that the work is done correctly and according to all applicable codes.  This is important for your safety.
• Some valves incorporate the advantages of both flap and gate valves into a single design.  Your plumber or contractor can advise you on the relative advantages and disadvantages of the various types of backflow valves.
• Valves should be installed on all pipes that leave the home or that are connected to equipment that is below the potential flood level.  So valves may be needed on washing machine drain lines, laundry sinks, fuel oil lines, rain downspouts, and sump pumps, as well as sewer/septic connections.
• If you have a sump pump, it may be connected to underground lines, which may be difficult to seal off.

Estimated Cost

Having a plumber or contractor install one backflow valve will cost you about $525 for a combined gate/flap valve or about $375 for a flap valve.  These figures include the cost of excavation and backfilling.

Raise Electrical System Components

Electrical system components, including service panels (fuse and circuit breaker boxes), meters, switches, and outlets, are easily damaged by flood water.  If they are inundated for eve short periods, they will probably have to be replaced.  Another serious problem is the potential for fires caused by short circuits in flooded systems.  Raising electrical system components helps you avoid those problems.  Also, having an undamaged, operating electrical system after a flood will help you clean up, make repairs, and return to your home with fewer delays.

As shown in the figure below, all components of the electrical system, including the wiring should be raise at least 1 foot above the 100 year flood level.  In an existing home, this work will require the removal of some interior wall sheathing (drywall, for example).  If you are repairing a flood damaged home or building a new home, elevating the electrical system will be easier.

Keep these points in mind when you have your electrical system components raised:

• Electrical system modifications must be done by a licensed contractor, who will ensure that the work is done correctly and according to all applicable codes.  This is important for your safety.
• Your contractor should check with the power company about maximum height that the electric meter can be raised.
• If your home is equipped with an old style fuse box or low amperage service, you may want to consider upgrading to a modern circuit breaker system and higher amperage service, especially if you have large appliances or other electrical equipment that draws a lot of power.

Estimated Cost

Raising the electrical service panel, meter, and all of the outlets, switches, and wiring in a 1,000 square foot, single story home will cost about $1,500 to $2,000.  If this work is performed during the repair of a damaged home or construction of a new home, the cost may be much lower.

Raise or Floodproof HVAC Equipment

Heating, ventilating, and cooling (HVAC) equipment, such as a furnace or hot water heater, can be damaged extensively if it is inundated by flood waters.  The amount of damage will depend partly on the depth of flooding and the amount of time the equipment remains under water.  Often, the damage is so great that the only option is replacement.

In floodprone homes, a good way to protect HVAC equipment is to move it from the basement or lower level of the home to an upper floor or even attic.  A less desirable method is to leave the equipment where it is and build a concrete or masonry block floodwall around it.  Both of these methods require the skills of a professional contractor.  Relocation can involve plumbing and electrical changes, and floodwalls must be adequately designed and constructed so that they are strong enough and high enough to provide the necessary level of protection.

Keep these points in mind when you have your HVAC equipment raised or floodproofed:

• Changes to the plumbing, electrical system, and ventilating ductwork in your home must be done by a licensed contractor, who will ensure that the work is done correctly and according to all applicable codes.  This is important for your safety.
• If you are having your existing furnace or hot water heater repaired or replaced, consider having it relocated at the same time.  It will probably be cheaper to combine these projects than to carry them out at different times.
• Similarly, if you have decided to raise your HVAC equipment, consider upgrading to a more energy efficient unit at the same time.  Upgrading can not only save you money on your heating and cooling bills, it may also make you eligible for a rebate from your utility company.
• If you decide to protect your HVAC equipment with a floodwall, remember that you will need enough space in the enclosed area for system repairs and routine maintenance.  Also, depending on its height, the wall may have to be equipped with an opening that provides access to the enclosed area.  Any opening will have to be equipped with a gate that can be closed to prevent flood waters from entering.

Estimated Cost

Having your furnace and hot water heater moved to a higher floor or to the attic will cost about $1,500.  The cost of a floodwall will depend partly on its height and length.  A 3 foot high wall with a perimeter length of 35 feet would cost about $1,000.

Anchor Fuel Tanks

Unanchored fuel tanks can easily be moved by flood waters.  This can be hazardous to you, your family, and your home, but also to public safety and the environment.  An unanchored tank outside your house can be driven into your walls, and it can be swept downstream, where it can damage other homes.  When an unanchored tank in your basement is moved by flood waters, the supply line can tear free and your basement can be contaminated by oil.  Even a buried tank can be pushed to the surface by the buoyant effect of soil saturated by water.

As shown in the figure below, one way to anchor a tank is to attach it to a large concrete slab whose weight is great enough to resist the force of flood waters.  This method can be used for all tanks, both inside and outside your home.  You can also anchor an outside tank by running straps over it and attaching them to ground anchors.

Keep these points in mind when you anchor a fuel tank:

• If you prefer not to do this work yourself, you can have a handyman or contractor anchor your tank.
• Extend all filling and ventilation tubes above the 100 year flood level so that flood waters cannot enter the tank.
• Close all connections when flood warnings are issued.

Estimated Cost

Anchoring a 1,000 gallon fuel tank to a concrete base will cost you about $300 to $500.  Using straps and ground anchors will cost about $300.

Adding Waterproof Veneer to Exterior Walls

Even in areas where flood waters are less than 2 feet deep, a house can be severely damaged if water reaches the interior.  The damage to walls and floors can be expensive to repair, and the home may be uninhabitable while repairs are made.

One way to protect a home from shallow flooding is to add a waterproof veneer to the exterior walls and seal all openings, including doors, to prevent the entry of water.  As shown in the figure below, the veneer can consist of a layer of brick backed by a waterproof membrane.  Before the veneer is applied, the siding is removed and replaced with exterior grade plywood sheathing.  If necessary, the existing foundation footing is extended to support the brick.  Also, because the wall will be exposed to flood water, changes are made to the interior walls as well so they will resist moisture damage.  In the area below flood level, standard batt insulation, and any wood blocking added inside the wall cavity is made of exterior grade lumber.

Keep these points in mind if you plan to have waterproof veneer added to the exterior walls of your home:

• Adding a waterproof veneer is appropriate in areas where the flood depth is less than 2 feet.  When flood depths exceed 2 feet, the pressure on waterproofed walls increases greatly, usually beyond the strength of the walls.  If greater flood depths are expected, consult with a licensed civil or structural engineer before using this method.
• Changes to the foundation of your home must be done by a licensed contractor, who will ensure that the work is done correctly and according to all applicable codes.  This is important for your safety.
• If your home is being remodeled or repaired, consider having the veneer added as part of the remodeling or repair work.  It will probably be cheaper to combine these projects than to carry them out separately.
• If your home has brick walls, you can still use this method.  The new brick veneer and waterproof membrane are added over the existing brick.
• If your home is flooded by groundwater entering through the floor, this method will not be effective.

Estimated Cost

If you have a contractor add a waterproof brick veneer to your home, you can expect to pay about $10 per square foot of exterior wall.  For example, a 3 foot high brick veneer on a house measuring 60 feet by 30 feet would cover about 540 square feet and would cost about $5,400.  This figure does not include the cost of sealing doors and other openings or extending the foundation.

References

Homeowner’s Guide to Retrofitting – Six Ways to Protect Your House From Flooding, FEMA 312 (6/98)

Protecting Your Property from Flooding, FEMA (1994)

Other Sources of Information

Repairing Your Flooded Home, FEMA 234 (1992)

Flood Emergency and Residential Repair Handbook, FIA-13 (1986)

Retrofitting Flood-Prone Residential Structures, FEMA 114, (1986)