June 27, 2008

Recent flooding and heavy rains have many Midwesterners cleaning and drying out homes, basements and crawlspaces. However, next time heavy rains hit, the potential for water and flood damage can be reduced, a UNL housing and environment specialist said.

Draining water away from the foundation, moving items up and out of harm's way, allowing materials to drain and dry faster, and making repairs easier all can help reduce flooding potential and time spent cleaning up the mess, said Shirley Niemeyer, UNL housing and environment specialist.

"By planning for a potential water or flood event, you can prevent some damage to interior contents and reduce the loss of important items," Niemeyer said.

Be sure to check with local housing and code officials about local codes before making changes.

To be sure water drains away from the home and foundation: 

• Have a 5-10% slope away from the home or about 1 inch per foot for a minimum of 10 feet. This will help reduce foundation leakage. Continue to slope away from the house to drain the water.
• Clean and repair gutters, downspouts and extenders. A minimum of one-sixteenth inch slope for every 10 feet of gutter length is needed to carry water to downspouts. Downspout extenders should empty the water well away from the foundation or to about 6 to 10 feet. Add gutters and downspouts if there are none. If gutters overflow, consider larger gutters or adding more downspouts to remove the water.
• Fill in any low spots around the foundation and make sure the soil is compacted.
• Use a hose on the foundation exterior to find water entry locations. Repair foundation cracks and holes.
• Window wells should have drains linked to the foundation drains. A drain pipe filled with gravel is a common way to create this drain. If there is no drainage system in the window well, make sure water flows well away from the well. Consider making a modified roof over the window well to reduce water entry. Windows should be carefully caulked and weatherstripped.

Hire a professional to move key utility and other equipment out of harm's way.

• Raise the main breaker or fuse box and the utility meter above the potential flood level for your home or to a higher floor.
• Raise outlets and switches to higher levels in rooms if allowed by local or state codes.
• Install ground fault circuit interrupters to prevent electrical hazards.

These items also can be raised to avoid damage:

• Heating equipment and air conditioners can be put on higher levels or a higher floor or possibly in the attic. Floor reinforcements may be needed to handle the extra weight.
• Outside air conditioners can be installed on a higher platform above potential water levels.
• Washers, dryers and water-conditioning equipment can be relocated to higher floors or raised onto secure platforms about 12 inches above the projected flood levels inside lower levels. Provide spillage pans and overflow drains to prevent water damage from leaks. Floor reinforcement may be needed.
• If equipment can't be moved to higher levels, construct sturdy platforms and raise them up from the existing floor level.
• Interior lower floodwalls can be built around equipment to protect against shallow water if the equipment can't be raised. A concrete or block floodwall can be made water resistant using plastic or water sealant products. However, the exterior water pressure may collapse the floodwall and water still may seep through.

To make repairs easier and to allow for faster drying:

• Use non-paper gypsum wallboard or cement board. Place it horizontally on the wall to make it easier to remove. If the water level is less than a few feet, the lower wallboard and insulation may only need to be removed. Wicking frequently will wet wallboard above the initial water level. Mold can occur within a wet wall cavity.
• Leave a gap between the lower and upper horizontal wallboards to allow for drying and to prevent wicking between the two. However, this may reduce the energy efficiency of the wall materials. Caulk the gap to reduce moisture wicking from one wallboard to the other. Cover the gap with a trim or railing that is easy to remove for faster drying.
• Leave a gap at the bottom of the gypsum wallboard to allow for drainage and drying. Attach floor moldings for easy removal and to allow inner wall cavities to drain and dry.
• Metal studs and sill plates that are corrosion resistant may be easier to clean.
• Use flooring materials, such as tiles and concrete, that resist water damage. If you think you must use soft coverings (carpet), use area rugs that can be rolled up and removed before the water enters. Rugs also are easier to clean because they can be moved outside to dry and to be cleaned professionally. Installed carpets and pads usually should be removed and disposed of after a water or flood event unless the water is clean or it is a minor water event.

To reduce water and flood damage in homes:

• Install check valves or back-flow valves in plumbing and sanitary sewer lines to prevent floodwater from backing up into the drains.
• If items must be stored in the lowest levels, store them high off the floor where they will be less likely to be damaged by water.
• Keep valuable items out of basements and off the first floor if it is subject to flooding.
• Keep copies of valuable documents and photos at another location, in a safety deposit box, or with relatives or friends outside the area.
• If you have a flood warning and have sufficient time, consider temporarily moving those items that are most meaningful to another location outside the high-risk area.

For more information about disasters and floods, go to www.eXtension.org and click on disasters and floods.