Severe storms, including hurricanes, strong winds, and floods are one of the biggest threats to housing and businesses. As climate change accelerates, so do the likelihood of these storms, their severity, and the effects of their damage. Although there are no more storms than there were in the past, the storms we have today are more severe, with more rain and higher winds.
One of the biggest problems caused by major storms today is flooding. Although flooding can also be caused by rising tides and continental drift, one of its main causes in the US is severe storms. Flooding can make houses unlivable, destroy businesses or even entire neighborhoods, and seriously devalue what was once prime building land. The question is, how can we adapt to more frequent flooding?
The basic types of flood resistance
This is the simplest and direct way to avoid flood damage. The goal here is exactly what it sounds like — moving your home/property away from the floodplain and to a place out of harm’s way. This is a simple enough solution, but simply not an option for many.
The idea behind wet floodproofing is that floodwaters will actually enter the building. This may seem counterintuitive, but it makes sense. As the floodwaters inside the building match the outside of the building, the hydrostatic pressure is greatly reduced. Hydrostatic pressure is the pressure from the floodwater outside the house pressing in on it. When this pressure is equalized, the loads held up by the house are more balanced and the likelihood of structural damage is seriously decreased.
Wet floodproofing requires the following:
- An entry and exit point within the home for the floodwaters that does not require pumping.
- The floodwaters must rise and fall at the same rate as the outside floodwaters.
- The areas of the home that are below the level of the floodwaters must not be too damaged. Basements and lower floors will require some kind of protection.
- Important equipment must be kept out of the waters or protected. Equipment like electrical fuse boxes, boilers, furnaces, and more must be elevated or waterproofed to prevent damage.
- High-value items must be kept out of the flooding area of the building.
- All parts of the house that will accommodate floodwaters must be designed to be resistant to water damage and flood damage.
This type of floodproofing can be a lot of work. Not only does the building have to be built to hold and release floodwaters, but it must also be built to easily be cleaned afterward. Materials used must be flood-resistant, and the modifications made on the home are typically extensive.
Dry floodproofing is when the outside of the building is sealed off to prevent the entry of floodwaters. It is good for areas with frequent flooding of small amounts (2-3 feet of floodwaters). It is also only viable on structurally-sound enough constructions, typically made from concrete or masonry. The area at and below the floodwaters is sealed, and the walls of the house resist the hydrostatic pressure.
Dry floodproofing requirements:
- The exterior lower part of the home must be sealed off.
- Openings below the ground floor, such as basement windows, pipes, and more need to be covered or sealed.
- The sealing must be strong on the outside and existent on the inside to prevent water from seeping in.
- Equipment outside the building must be protected. Electrics like transformers, power lines, and any other important equipment must either be elevated or sealed to prevent damage from floodwaters.
Dry floodproofing does have some drawbacks. It is only viable for sturdy buildings with little area below floodwaters. There is often seepage when a building is surrounded by floodwaters. This means a pump and cleaning will be required afterward to remove any water inside the house. Dry floodproofing also requires extensive work be done to modify the house as well.
For more in-depth reading on both dry and wet floodproofing, the FEMA homeowner’s guide to floodproofing has plenty of good advice.
If you’ve ever seen sandbags piled up by a river to prevent flooding, you’ve seen a floodwall. Floodwalls can be constructed on the spot with sandbags, or they can be built permanently to surround a home, business, or entire area. Permanent floodwalls often require approval from zoning commissions/city/local/national governments. One of the reasons for the red tape is that floodwalls just push the water further down the floodplain, making it another person’s problem.
Other Floodproofing Methods
This technique dates back to ancient times, but has fallen out of favor in the modern era until recently. Most commonly, you will see this manifest as buildings built on stilts. A house/business built 10-12 feet above a flood plain on stilts will have significant resistance to high floodwaters.
- This option is most viable for houses. Businesses are often too big to be built entirely on stilts.
- The home must be built on stilts from the first stages of building. Homes can not usually be remodeled and placed on stilts.
Fortunately, another option to using stilts is to build the home on an artificially constructed mound of earth that raises it out of the floodplain. This option is good, but building a solid, raised foundation is expensive and time-consuming.
Some new buildings are built with foundations that work as rafts. Again, like elevation, it works better for smaller buildings like houses than it does for large businesses. The house must also be built on a raft foundation from the start, it’s not a modification that can be performed later.
Looking to floodproof?
Reliable Commercial has got your back. We work on constructions, remodeling, renovation, and more. Our 35 years of experience, large team, and work ethic mean no job is too big or difficult. If you are looking for construction contractors who will be straight-up, cost-effective, and smart, look no further. We can help you assess your flood risk, perform floodproofing work, and build flood-resistant buildings. Get in contact with us today to see what we can do for you.