An Overview ofAn Overview ofA-Zones vs. V-ZonesA-Zones vs. V-Zones

M. Sean Welsh, CFMAssistant Flood Plain Administrator

Galveston County

OverviewOverview

This presentation will be broken up into 3 parts.• Part 1 will be explaining what an A-Zone is and

what building regulations apply to them.• Part 2 will be explaining what a V-Zone is and

what building regulations apply to them.• Part 3 will be talking about what the similarities

and differences between A and V Zones in regard to construction practices and uses below the BFE.

What is an A-Zone?What is an A-Zone?

• An A-Zone is an area on the flood map that has been determined by FEMA to have a 1 percent chance of having a 100 year flood in any given year.

• This area of flooding would have wave heights of less than 3 feet during the 100 year flood.

A-ZoneA-Zone

• How high does the first floor of the structure have to be?

• Where is it measured from?

Elevation of a Structure in an Elevation of a Structure in an A-ZoneA-Zone

• Fill or Pilings?

• Either may be used as long as it meets the elevation and resists flotation and lateral movement.

A-ZoneA-Zone

• Can you have an enclosure below the BFE?

A-ZoneA-Zone• Yes, you may have an

enclosure below the BFE as long as it is vented with at least 1 square inch of open space per square foot of enclosed area. This open space should be divided between at least 2 different walls and the openings start within 12 inches of the floor.

A-ZonesA-Zones• Are there any restrictions in the use of the

area in the area below the BFE?

• Yes. Parking, Storage and Building Access.

V-ZonesV-Zones

• What is a V-Zone?

V-ZoneV-Zone

• A V-Zone is an area on the flood map that has been determined by FEMA to have a 1 percent chance of having a 100 year flood in any given year. This area of flooding would have wave heights of 3 feet or more during the 100 year flood.

V-ZoneV-Zone

• How high do you have to build in a V-Zone?

V-ZoneV-Zone• The bottom of the lowest horizontal structural

member has to be at or above the BFE. The structure also has to be able to sustain the simultaneous effects of wind and water loads during the 100 year event.

V-ZoneV-Zone

• Can you have an enclosure below the BFE?

V-ZoneV-Zone

• Yes. It must have break away walls.

• A break away wall is a wall that will collapse with 10 to 20 pounds of pressure put on the wall without damage to the elevated portion of the building.

V-ZoneV-Zone• Are there any restrictions in the use of the

area below the BFE?

• Yes. Parking, storage and building access.

Questions?Questions?