My house is in a floodplain. What do I do if I want to build an addition or otherwise improve it?

If the value of the addition or improvement to the residential structure is less than 50% of the market value of the existing structure, you need only make sure that the improvement meets or exceeds the standards that were used in constructing the existing structure (assuming the existing structure was built in compliance at the time it was constructed). Additions or other improvements valued at 50% or more of the market value of the existing structure are considered substantial improvements. In such cases, the entire structure must be brought into compliance with the elevations on the map in effect at the time the improvement begins.

Under certain circumstances, only the addition needs to be elevated to the flood elevations shown on that map. Please note, however, that there may be more stringent state or local requirements that take precedence over those stated here. Regardless of whether your building is substantially improved, you will likely need a building permit to make the improvement and need to contact your local building official.

Create a FIRMette of my property.

Show All Answers

1. What factors determine flood insurance premiums?
2. My house was not in a floodplain according to the old map, but the new map shows it as being in a floodplain. Will I have to purchase flood insurance now?
3. I have flood insurance, and my house is in a floodplain according to the old map. The new map, however, shows my house as being outside the floodplain. Do I need to continue carrying flood insurance?
4. My house was built to the flood elevation on the current/previous map. On the new map, my house remains in the floodplain, but the flood elevation will increase. What happens to my insurance premiums?
5. My house was built to the flood elevation shown on the previous map. On the new map, my hose remains in the floodplain, but the elevation decreased. What will happen to my insurance premium?
6. My house was in a floodplain on the old map. On the new map, my house remains in the floodplain, but the flood elevation increased. Is my house being considered to be in violation of NFIP regulations?
7. My house is in a floodplain. What do I do if I want to build an addition or otherwise improve it?
8. Was my property affected by the new FIRM maps?