Case Study:
Move Up and Move Back

Existing structures that are threatened with coastal flooding or erosion often can be moved up. If you are located in a flood zone, your town may require that the lowest structural part of your house be a minimum of one foot above the base flood elevation (this is typically the minimum standard).

If your structure is older and has been flooded and does not meet current standards, or any time you are doing substantial improvements to your structure, consider the cost of elevating the structure using a flow-through foundation or a pile foundation, especially if structure improvements meet or exceed 50% of the value of the structure.

Flow-through foundations are typically block or poured cement foundations with adequate spacing for floodwaters to flow through the foundation without damaging the supports. These structures are acceptable in the A-zone areas of back dune environments that are not considered to be Erosion Hazard Areas.	Pile foundations are typically used in more active flooding areas along open ocean coastlines, and provide much more open space for floodwaters to travel through. Piles are required in the frontal dune and in areas of the back dune classified as Erosion Hazard Areas.

The concept behind both foundation types is that water, sediment, and debris travel through the foundation, instead of applying pressure and lateral force to the foundation which can cause structural failure. Both foundation types can significantly reduce potential flood damage to a structure.

In some areas, fill can be added below a foundation to increase the elevation of the structure to meet floodplain standards. This technique is not recommended, as it can result in potential increased flood hazard impacts to adjacent properties.

Many of the state requirements regarding elevation of structures, including a review of techniques, are outlined in Chapter 5 of the Maine Floodplain Management Handbook. Your town may have additional requirements that meet or exceed minimum state standards. Contact your local Code Enforcement Officer for more information.

You may also want to review the FEMA Coastal Construction Manual and the FEMA Home Builder’s Guide to Coastal Construction Technical Fact Sheets. The Coastal Construction Manual is available as a CD or in print copy by calling FEMA Publications Distribution Facility at 1-800-480-2520, and should also be available for review at your local town office or public library.

Refer to Chapter 305 (Permit by Rule), Chapter 310 (Wetlands) and Chapter 355 (Coastal Sand Dune Rules) for additional requirements relating to impacts to coastal sand dunes associated with elevating structures.

If you consider elevating your structure, think about making other improvements to make your home more storm and flood resilient. Also, consider elevating your structure over and above the elevation required by your floodplain ordinance, in order to take into account expected rates of sea-level rise and higher future floodplain elevations. The State of Maine has adopted an expected rise in sea level of 2 feet over the next 100 years.