The Constructor

Flood Damage-Resistant Building Materials

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Building materials that can withstand direct or prolonged contact with flood water for at least a period of 72 hours without significant damage are considered flood damage-resistant building materials. 

Common flood damage-resistant materials are concrete, ceramic tile, pressure-treated and marine-treated plywood, pressure-treated lumber, latex or bituminous, bricks, metals, etc. The type of flood-resistant material used for floor and walls vary.

Flood damage-resistant materials are used for building elements like walls, floors, or other buildings that are constructed below base flood elevation (BFE) or 100-year flood level. The BFE refers to the elevation associated with the "100-year flood," or a flood with a 1% chance of occurrence in any given year. 

This article discusses the flood damage-resistant materials used to construct buildings in special flood hazard areas (SFHAs).

Classification of Flood Damage-Resistant Materials

The National Flood Insurance Program (NFIP) regulations include minimum building design criteria for new, existing, and repair of highly damaged buildings in SFHAs. 

A few examples of flood damage-resistant materials used in construction are given in the table below:

Floor Materials
1. Concrete, concrete tile, and pre-cast concrete 
2. Latex or bituminous, ceramic, clay, terrazzo, vinyl, and rubber sheets and tiles 
3. Pressure-treated (PT) or decay-resistant lumber 
4. PT wood and cold-formed steel 
Wall and Ceiling Materials
1. Brick, metal, concrete, concrete blocks, stones, cement board
2. Polyester epoxy paint
3. Decay-resistant wood
4. Foam and closed-cell insulation
Other Materials
1. Hollow metal doors
2. Cabinets
3. Foam or closed-cell insulation
Table-1: Different Flood Damage-Resistant Materials

NFIP regulations and the Federal Emergency Management Agency (FEMA) describes five classes (Table-2) of materials categorized from those highly resistant to floodwater damage to those without resistance to flooding based on their applications in construction. 

The classification is based on base flood elevation (BFE), the height of the base flood in relation to a specified datum, usually the National Geodetic Vertical Datum of 1929 or the North American Vertical Datum of 1988. As per NFIP, all construction below BFE is susceptible to flooding and must be constructed using flood-damage-resistant building materials.

Note: Special Flood Hazard Area (SFHA)¬†is the area delineated on a FIRM as being subject to inundation by the base flood and designated as Zone A, AE, A1-A30, AR, AO, AH, A99, V, VE, or V1-V30. Flood Insurance Rate Map (FIRM) ‚ÄĒ is the official map of a community on which FEMA has delineated both the special flood hazard areas (SFHAs) and the risk premium zones applicable to the community.

Table-2: Class Description of Materials Based on Their Resistance to Flood Water Damage Source: fema.gov

The flood damage resistance depends on the application and the characteristics of the floodwater. Based on the probable contaminants present in the water, a proper judgment of materials is made. Classes 1, 2, and 3 are not used for flood-resistant buildings.

The table below shows a consolidated list of class 5 and class 4 materials used for floor, wall, or ceiling construction under the BFE level.

Table-3: Examples of Structural and Finishing Materials for Flood-Resistant Floor and Wall Construction

A more detailed list of materials is given in the technical bulletin fema.gov. 

The Masonry and wood products used below the BFE must comply with the applicable standards published by the American Society for Testing and Materials (ASTM), the American Concrete Institute (ACI), the Truss Plate Institute (TPI), the American Forest & Paper Association (AF&PA), and other appropriate organizations. 

Fasteners and connectors involved in flood-resistant construction must be made of flood-damage-resistant materials to comply with the NFIP requirements. The specifications of fasteners and connectors used in buildings in SFHAs are given in ASCE 24.

The International Building Code (IBC ), according to ASCE 24 Flood Resistant Design and Construction, the International Residential Code (IRC) require flood damage-resistant materials for constructing flood-resistant buildings. 

FAQs

What are flood damage-resistant building materials?

Building materials that can withstand direct or prolonged contact with flood water for at least a period of 72 hours without significant damage are considered flood damage-resistant building materials. 

What are the different classes of flood damage-resistant materials?

NFIP regulations and the Federal Emergency Management Agency (FEMA) describes five classes-Class 1,2,3,4 and 5 of materials categorized from those highly resistant to floodwater damage (5 and 4) to those without resistance to flooding (3, 2, and 1) based on their applications in construction. 

What are the best flood damage-resistant materials for wall construction?

Concrete, gypsum products, and cement boards are some of the flood-damage materials for building wall construction.

Read More

Design and Construction Requirements for Flood Prone Building Structures

Measures to Increase Ductility of Reinforced Concrete Structural Members

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