Elevate Your Home Above Grade
05/03/2023
Plan | Stay Safe • Floods | Tsunamis
Why does it matter?
If you live in a tsunami risk zone, elevating your house above grade can help reduce the risk of property damage and protect you and your family better if you are unable to evacuate in time. Tsunami waves can reach heights of 100 feet or more, but many tsunamis have waves less than 10 feet in height. Prepare your home for these more common tsunamis.
What do I need to know?
- Contrary to common belief, a tsunami is not one large wave, but a series of waves.
- Tsunami waves can travel at speeds up to 450 miles per hour.
- Smaller tsunami waves are just as destructive and dangerous as the larger ones.
Where Do I Start?
- For your existing home, consult an engineer to evaluate the condition of your home and suggest actions to make it more resistant to tsunamis. There may be ways to divert potential waves and floodwaters. Improper methods of diverting waves and water could make things worse, so consult a professional.
- In new construction, consider elevating your coastal home on piers or pilings like homes in the FEMA NFIP V-Zone. (link to Know Your Flood Zone)
- Having an elevated home allows the tsunami waves and related storm surge to pass underneath the house and thereby reduce potential damage.
- Talk to your local officials, such as in the building department, floodplain management, or hazard mitigation office, to determine expected waves heights for your specific location.
- An engineer can design the structure to resist the waves forces as well as scour, which can affect the pilings.
- Consider building any new structure out of concrete instead of wood due to the reinforced qualities.
- If the property layout allows, consider orienting the structure at an angle to the shoreline so any future wave impacts will not be direct impacts on the building.
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