Often it’s not the wind from a hurricane that does the most damage, it’s the water, particularly when a storm lingers and dumps huge amounts of rain over one area. But sometimes, a waterlogged house can be saved.

“A high water depth doesn’t mean the home is destroyed,” said Claudette Hanks Reichel of Louisiana State University’s Agricultural Center, who has written disaster recovery material for the U.S. Department of Housing and Urban Development. “But if a house was already structurally compromised by decay, termites or very poor construction, then the flood could be the last straw.”

So what does a major deluge do to a house?

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Flooded home

Flooded home

Flooded home

Cracks the foundation

Serious foundation damage is common in areas where the soil is mostly clay and where most homes are built on concrete slabs. Many coastal areas fit this description. Saturated clay expands unevenly and lifts parts of a slab, causing it to crack or break. Embedded pipes can rupture, exterior walls can crack, the roof can sag. As the soil dries and shrinks, it all gets worse. Sometimes, moving water erodes the soil from below the slab, and a poorly secured house will simply float off its foundation. No one should enter a house that looks cracked or off-kilter before a structural assessment.

Jams (or breaks) windows and doors

Jean-Pierre Bardet, a geotechnical engineer and dean of engineering at the University of Miami, said one of the first signs of foundation damage is that doors and windows won’t open or close because their frames have become distorted by the shifting house, sometimes so much so that the glass twists and breaks. Glass could also be broken by floating debris.

Weakens drywall

Hurricane Harvey aftermath, 2017 (Jabin Botsford/The Washington Post)

Water weakens regular drywall, and the paper facing provides food for mold. If drywall is soft, crumbly or moldy, it has to be replaced. Plaster and other materials may dry, but walls and ceilings that were in contact with water still need to be gutted down to the framing so that the insides can be cleaned and dried to prevent mold.

Soaks insulation

Most insulation used in homes is made of fibers or foams that hold water, so it has to be replaced if it gets wet. But other types, such as closed-cell foam, don’t absorb water and can survive a flood.

Degrades sheathing

Many common types of structural sheathing — the large panels between the framing and the outside of the house — are a composite of wood chips or other porous material. Those will absorb water, swell and lose strength. Plywood sheathing probably will be fine after it dries out.

Temporarily swells framing

Here’s some good news: Most homes are framed with solid wood lumber, which usually withstands flooding quite well unless it sits in water for weeks or was already damaged. Even if the wood soaks up some water and swells, it should return to shape and maintain its structural integrity. All framing has to be cleaned thoroughly and dried quickly to prevent mold, which flourishes in warm, moist areas.

Wrecks (some of) the electrical system

Hurricanes can cause flooding from two types of water: freshwater (rain) and saltwater (storm surge). Electrically speaking, rain is better, because saltwater is corrosive. Any outlets and switches that were underwater need to be replaced regardless. But some of the wiring may survive, pending a building inspector’s approval.

Ruins appliances

Hurricane Harvey aftermath, 2017 (Win McNamee/Getty Images)

Reichel said that insulated appliances, such as refrigerators and ovens, are almost never salvageable because water penetrates the insulation. Washers, dryers and microwave ovens may be usable after they are examined by a professional.

Contaminates furniture

Hurricane Harvey aftermath, 2017 (Michael Robinson Chavez/The Washington Post)

Most upholstered furniture, mattresses and draperies should be tossed. Floodwater from a storm is a nasty soup of microorganisms from sewage leaks, chemical spills and everyday contaminants. Properly cleaning all but the most valuable pieces would probably cost more than replacing them. Soaked particle-board furniture will fall apart, but pieces made of hardwood, metal, concrete, plastic and glass should be fine after they are thoroughly cleaned.

Spoils (some) flooring

Hurricane Harvey aftermath, 2017 (Michael Robinson Chavez/The Washington Post)

Any carpet and padding that was covered in water will have to go because it’s just too hard to clean. Laminate flooring will usually peel apart. Hardwood floors may survive with a lot of TLC, such as removing a few boards here and there to let the others expand so that they don’t warp. Some tile may just need to be cleaned, but even usable flooring may need to be temporarily removed to clean and dry out the subflooring.

Homes that took the brunt of a hurricane’s winds or were caught in fast-moving floodwater are likely to be damaged beyond repair.

However, some flooding involves relatively calm water that simply rises higher and higher until homes are inundated but not destroyed. This means many homeowners will have to do a painful calculus: Is the house worth saving?

“The deeper the water, the more extensive and expensive the restoration project,” said Reichel. “It’s not just the cost, it’s the ordeal, and the time and competing for contractors and materials. It’s a horrendous, stressful situation.”

People who choose to fix their homes have a chance to make their houses more resistant to future floods. Here are a few recommendations from the LSU AgCenter:

  • Rebuild the house at least two feet higher off the ground than the area’s zoning requires. (It is also pricey but possible to raise an existing house.)

  • When restoring walls, use closed-cell foam insulation and flood-damage resistant sheathing and wallboard. Leave drainage space so that water or mud can be cleaned out without tearing up the walls.

  • Choose flooring for the first level of the house that is made of ceramic tile with water-resistant mortar, interlocking tile, concrete or other nonporous material.

  • Elevate important items, such as major appliances and HVAC components, off the ground.

Reichel said these measures cost more initially but can save money and headaches if another flood occurs. “If you can’t afford to do everything,” she said, “anything you do will reduce your damage next time.”

About this story

Originally published Sept. 1, 2017.

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