What are Flood Resistant Buildings?

Senior Associate John Squerciati explains flood resistant buildings in about 180 seconds.

Hi, I'm John Squerciati. Today I'd like to talk to you a little bit about flood resistant building techniques. These are techniques that we use to reduce or eliminate the risk of future flood damage to buildings.

The first most effective technique is to simply locate the building outside the floodplain. For new construction, this can be accomplished by checking the flood maps and then not building within the floodplain. But for existing buildings that are located in the floodplain, we can acquire the building and then demolish it, or in some cases we can physically relocate the building outside the floodplain. In either case, we would deep restrict the site so that no future development could occur there and we would make sure the site is restored to its natural condition.

The next best flood resistant building technique is to elevate the building above the flood level. For new construction, this can be done by designing the building so its lowest floor is located at or above the flood level. And for existing structures, there's a couple of different ways to accomplish this. We can physically lifted building and build an elevated foundation system underneath it. We can abandon a lower floor, or in some cases, we can demolish the building entirely and build a new elevated building in accordance with local codes and standards.

If neither of these approaches are feasible, then wet or dry flood proofing can reduce the risk of flood damage. Dry flood proofing techniques essentially make the building watertight by adding sealants to the walls, shields to the openings and secondary drainage and pumps to remove the water that seeps inside the building. This technique is good for concrete or masonry construction with low levels of flooding. But it does require significant levels of maintenance.

By contrast, wet flood proofing techniques allow the water to enter the structure but they use flood damage resistant materials, hydrostatic openings and protection of key equipment and contents to limit the damage. Wet flood proofing can be an effective and low cost technique. However, there is still a significant amount of posts flood cleanup that will need to be done.

The last flood resistant building technique is to place a permanent barrier around the structure to prevent flood waters from reaching it. This can be done by the use of a floodwall constructed of concrete or masonry, or using a levy constructed of compacted layers of soil with an impervious core. Both floodwalls and levies do require significant maintenance. In addition, levies will require significant amount of land as well as usable soil materials to construct them.

Remember, you can check if you're building is located in the floodplain by going to FEMA's Maps Service Center website and entering the property address. If you're building does turn out to be located in the floodplain, then it's important to check with the local floodplain management administrator as some community regulations may restrict or prohibit certain building techniques.

On behalf of Dewberry Explains, I'd like to thank you for your attention and listening to our discussion of flood resistant building techniques.