Three different places, depending upon what measurement is needed.
- Building Envelope (physical size of the building): From the bottom of the building (usually bottom of the floor joists) to the highest part of the building. Note: If the area under a building - including freeboard area - is enclosed more than 299 square feet, this becomes the lowest floor and contributes to building size.
- Flood Elevations: If built incorrectly, a concrete slab in a V-zone could be ruled the lowest horizontal supporting crossmember and the entire building would then be considered below flood; regardless of how high the first floor was built. Ask before you build. Types of flood zones:
- Type "A" Flood Zones: From sea level (NGVD) to the top of the first finished floor.
- Type "V" Flood Zones: From sea level (NGVD) to the bottom of the lowest horizontal supporting cross-member.
- Building Height: From the crown-of-the-road (at the highest point of the closest street adjacent to the building) to the uppermost part of the building