Constructing Buildings to Withstand Floods

Building materials that endure direct or prolonged contact with floodwater for at least 72 hours without significant harm are deemed flood damage-resistant. These materials are crucial for constructing elements like walls and floors in areas prone to floods, especially those below the base flood elevation (BFE) or the 100-year flood level.


Classifying Flood Damage-Resistant Materials

To ensure resilient construction, the National Flood Insurance Program (NFIP) establishes minimum design criteria for buildings in special flood hazard areas (SFHAs). Below, we explore flood damage-resistant materials classified by NFIP regulations:

Different Flood Damage-Resistant Materials

Floor Materials Wall and Ceiling Materials Other Materials
1. Concrete, concrete tile 1. Brick, metal, concrete 1. Hollow metal doors
2. Latex or bituminous, ceramic blocks, stones, cement board 2. Cabinets
3. Pressure-treated lumber 2. Polyester epoxy paint 3. Foam or closed-cell insulation
4. PT wood and cold-formed steel 3. Decay-resistant wood

Understanding Flood Damage Classes

NFIP, along with FEMA, categorizes materials into five classes based on their resistance to floodwater damage. This classification depends on the base flood elevation (BFE), the height of the base flood concerning a specified datum. Construction below the BFE requires flood-damage-resistant materials.


Determining Flood Damage Resistance

Flood damage resistance varies based on application and floodwater characteristics. Classes 1, 2, and 3 are unsuitable for flood-resistant buildings. Class 4 and 5 materials, suitable for construction under the BFE level.


Ensuring Compliance and Standards

Materials used below the BFE must comply with standards from organizations like ASTM, ACI, TPI, AF&PA, and others. Fasteners and connectors involved in flood-resistant construction must meet NFIP requirements. ASCE 24 provides specifications for these components.


Regulatory Requirements for Flood Damage-Resistant Construction

The International Building Code (IBC), ASCE 24 Flood Resistant Design and Construction, and the International Residential Code (IRC) mandate the use of flood damage-resistant materials in the construction of flood-resistant buildings. These regulations aim to enhance the resilience of structures in flood-prone areas.


In conclusion, selecting the right flood damage-resistant materials is crucial for building structures that can withstand the challenges posed by floods, ensuring the safety and longevity of the built environment.