If a new story is added that doubles a house's size and value, what must be done to the existing first floor?

When a new story is added to a house, effectively doubling its size and value, it typically triggers regulatory requirements under floodplain management standards, especially in flood-prone areas. One key requirement often involves elevating the structure to reduce the risk of flood damage.

In this context, elevating the existing first floor is necessary to ensure that the entire building complies with floodplain management regulations. This is crucial because structures need to be built or modified in a way that protects them from flood risks. Elevating the first floor helps to minimize potential damage by placing it above expected flood levels.

Maintaining the first floor as is, demolishing it, or merely remodeling it would not address the fundamental concern of meeting the floodplain management standards that aim to protect properties and lives from flooding hazards. Therefore, elevating the first floor effectively aligns with the goal of reducing flood vulnerability and complying with local floodplain management regulations.