Why does a flooded house need to be torn down?

Flooding after Hurricane Katrina. See more storm pictures.
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­Although water is essential for life, it can be destructive -- particularly when it comes in the form of a f­lood. Scien­tific and historical evidence suggest that a flood was one of the most massively cataclysmic events in human history. Today, we still struggle with periodic floods that continue to wreak havoc on communities. And when a flood strikes your home, the decision of what to salvage and what to let go of is particularly heart-wrenching.

To understand the damage a flood can cause, let's take a look at some of the common problems and hazards associated with a flooded home. Like the famous phrase, "water, water everywhere but not a drop to drink," floodwater is particularly dangerous. Because it picks up unsafe chemicals, mud and refuse, floodwater is very unclean. Not only is it unsafe to drink, but it also contaminates everything it touches -- and in a flood situation, that means almost everything in your home.

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­Even tap water isn't safe immediately after a flood: You'll need to strain, boil and add bleach to tap water to decontaminate it. But to make a flooded home safe enough to live in at all, you'll have to hose down all walls and hard floors using­ soap and water. Other things in a flooded house are even more difficult to clean. For instance, mattresses and wallboard can soak in contaminants that are almost impossible to get rid of. This is why experts advise disposing of things you suspect are contaminated.

To protect against future flooding in a flood-prone area, you'll also need to floodproof your home during renovations. This might mean adding waterproof seals, installing backflow valves in drains and getting shields for doors and windows [source: FEMA].

On top of all these precautions, structural damage in your home could call for significant repairs. Considering all these factors, you can understand how it might be cheaper -- and certainly safer -- to tear down a flooded home. Local regulations may even require it.

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Structural Flood Damage and Demolition of a Flooded House

Destroying the house is easy. Getting rid of the debris is more of a challenge, however.
Destroying the house is easy. Getting rid of the debris is more of a challenge, however.
©iStockphoto/Sonja Miokovic

­Even if your house isn't hit by impact loads, such as waves, floods can still impart lasting damage on your home. When your house is flooded, renovation is complicated by the fact that the inside of your home can remain waterlogged while the water outside your home subsides. For instance, your home may retain water that gets swept away outside. It could also happen if you pump out the water from your basement prematurely while the soil around it remains saturated with heavy floodwater [source: Rogers]. This causes hydrostatic loads that press toward the side of your house with the lower water level, causing walls and floors to collapse or crack. Hydrodynamic loads, which result from floodwaters flowing against and around the house, can not only cause similar physical pressures, but can also inundate your house with silt and soil tha­t can weaken the foundation.

If you see sagging ceilings and cracks in the basement or in foundation walls, they'll probably need to be replaced. As you can imagine, replacement of such fundamentals is usually costly and difficult. This is when tearing down a flooded home rather than repairing it might be more advantageous.

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Although it's a difficult decision, you may not even have a choice. Some local regulations won't let you repair the structure if damage exceeds half of the market value of your home. Other regulations may require that you raise your house higher off the ground and fill in the basement. The costs of complying with local regulations add to the benefits of demolition over repair.

This isn't to say that demolition comes cheap. Fortunately, flood insurance could cover at least some (or perhaps all) of the costs of demolition, elevating the home or floodproofing the structure under the Increased Cost of Compliance (ICC) coverage, which is designed to restore a home to regulation. So check your insurance policy to see what's covered before you make any rash decisions.

If demolition turns out to be the best option, you should know what to expect in the process. First, obtain any necessary permits you need for demolishing a house. Then, consider all the utility lines that are connected to your home, such as gas, water and electricity. You'll need to contact the utility companies to turn these off. Make sure your contractor disconnects or caps the connections as well before going forward with demolition. You'll need to dispose of asbestos and other dangerous materials properly before demolition. Check federal, state and local regulations for the legal ways to get rid of these materials [source: FEMA].

During the actual demolition, the contractor uses a bulldozer to knock everything down. Oddly enough, the physical tearing down of the structure is often the easiest and cheapest part of this process. The hard part is next: disposing of the debris. You might be able to get a permit to bury debris at the site, but many communities have policies against uncontrolled burials as a precaution for keeping soil uncontaminated [source: EPA]. Instead, you might need to have it hauled to a designated site and pay a fee for dumping it there. Although it depends on how much debris there is after demolition, disposal is usually the priciest part of demolition -- no matter what method you use.

As if deciding to tear down home sweet home wasn't hard enough, even more difficult decisions follow after demolition.

After Demolition of a Flooded House

After the demolition of your home, you have a few options. For one, you could decide to stay put and rebuild your home on your property's newly clean slate. Another option is to simply pick up and move out of a flood-prone area. Each choice has its own pros and cons.

The decision to rebuild on the same site rehashes some of the problems associated with repairing a flooded home. This includes floodproofing the home and local regulations that might require you to forego building a basement. You'll also have to build the structure at the proper elevation. One term to look out for when rebuilding is the base flood ele­vation (BFE). The BFE is the elevation that a 100-year flood is expected to reach (see sidebar). The first floor of your home should lie at or above the BFE to anticipate and curtail flood damage. You can accomplish this by planting the house on posts or columns, or you could build it on extended walls (of concrete, usually) with designated holes cut out to allow floodwater through [source: FEMA].

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One inherent disadvantage to rebuilding, though, is that you will need a temporary place to live during construction. Another obstacle is that you'll need to obtain yet another permit from the local authorities (in addition to the demolition permit) for rebuilding. Despite the disadvantages of rebuilding, it will allow you to design a house according to your preferences (as long as they fall within regulation). It will also avoid the problem of uprooting your family to a new area.

This brings us to your other option: moving. If you move to a different home in a new area, preferably out of the floodplain, you can leave behind all the stresses and building regulations of the old area. But, as appealing as this may sound, it also comes with some significant disadvantages. Most importantly, you'll have to consider what to do with the land you're leaving behind. If it's situated in a floodplain, selling it will be difficult. After all, not many people will be anxious to take on the problems that have driven you out. This is why federal, state or local programs may offer to help take the land off your hands [source: FEMA].

Most importantly, however, you can't abandon the land and wash your hands of it that easily. Although aid may be available to relieve you of your flood-damaged property, local regulations usually stipulate that you restore the old site before you leave. Restoration may include taking out any hardscaping, such as patios or driveways, and planting grass. The requirements also often stipulate that you restore the landscape that was damaged during demolition of the house. You should also check to see if you need a permit for restoration of a flooded site.

If you're lucky enough to have a large property with a portion that falls outside of the floodplain, you could take the middle road and rebuild your home there without the complicated floodproofing and regulatory requirements. However, you'll still need to find a place to live while you rebuild, and you'll have to restore the old site according to local regulations.

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Sources

  • American Red Cross, FEMA. "Repairing Your Flooded Home." American Red Cross, Federal Emergency Management Agency, 1992. (Dec. 9, 2008). https://americanredcross.com/static/file_cont333_lang0_150.pdf
  • CDC. "Flood: A Prevention Guide." Centers for Disease Control. Jan. 1, 1994. (Dec. 10, 2008). http://wonder.cdc.gov/wonder/prevguid/p0000371/p0000371.asp
  • EPA. "Planning for Disaster Debris." U.S. Environmental Protection Agency. Updated Dec. 11, 2008. (Dec. 16, 2008). http://www.epa.gov/osw/conserve/rrr/imr/cdm/pubs/disaster.htm
  • FEMA. "Other Ways to Make Your House Floodproof." Federal Emergency Management Agency. Nov. 20, 1998. (Dec. 10, 2008). http://www.fema.gov/news/newsrelease.fema?id=10678
  • FEMA. "Resource Record Details: Homeowner's Guide to Retrofitting." Federal Emergency Management Agency. June 1998. (Dec. 10, 2008). http://www.fema.gov/library/viewRecord.do?id=1420
  • Rogers, Craig D., P.E. "Structural Damage Due to Floods." Rimkus. (Dec. 16, 2008). http://util.rimkus.com/files/NEWS%20Structural%20Damage%20Due%20to%20Floods.pdf