BASC Search | Building America Solution Center

Moisture can migrate from below the foundation to the basement wall and insulation cavity in a conventional blanket insulation installation

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Right – This floor system on a column foundation is insulated using closed-cell spray foam rather than fibrous insulation

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Rigid foam provides the code-required insulation values for this floor and wall assembly so that fibrous cavity insulation can be avoided, reducing risk of floodwater damage

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This floor assembly above a vented crawlspace controls vapor and heat transmission by using foil-faced isocyanurate rigid foam insulation installed underneath the floor joists and fiberglass insulation in the floor joist cavities

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This flood-resistant masonry wall design with metal framing and rigid foam insulation will limit moisture damage in exterior walls.

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Right – The floor and wall system on this open-foundation home use rigid foam rather than fibrous cavity insulation to reduce risk of water damage.

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FEMA recommends techniques like open lower wall cavities with exterior rigid foam insulation and paperless drywall for flood-resistant, dryable wall interiors.

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For homes built on an open foundation, provide a continuous air barrier by sealing all joints between the rigid insulation, floor support beams, rim joist, and bottom wall plate

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Closed-cell spray foam insulates the floor above an open foundation; a protection board made of fiber cement is screwed in place under the floor joists to keep out pests

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Closed-cell spray foam insulates the floor above a vented crawlspace; a protection board made of fiber cement is screwed in place under the floor joists to keep out pests

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A dormer with an openable window (not shown) can provide access to the roof if flood waters rise too high and too quickly; the dormer should be properly insulated, flashed, and air sealed

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Green Coast Enterprises built this New Orleans home on piers so that the floor is 1 foot above the base flood level; borate treated framing and closed-cell spray foam insulation add to the home's moisture resistance.

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This raised-slab poured concrete foundation includes flood-resistant features such as a sloped grade, capillary break under the slab (gravel or sand), vapor retarder under the slab (rigid insulation), and capillary break at the top of the foundation wall

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Flood-Resistant Pier, Pile, Post, and Column Foundations

Guide

Guide describing how to construct flood-resistant homes using pier, pile, post, or column foundations.

Flood-Resistant Crawlspace Foundations

Guide

Guide describing how to design or retrofit a crawlspace to reduce the risk of damage during a flood event.

Roof Escape Openings for Flood-Prone Areas

Guide

Guide describing options for providing access to the roof via openable skylights, dormer windows, or roof hatches, for occupants of homes in areas prone to severe flooding.

Flood-hardy, drainable, dryable wall

Video

Video explaining a design option for homes in the case of a flood that would negate the need for gutting the home post-flood. Recommendations from LSU AgCenter.

Air Sealing Doors Adjacent to Unconditioned Space

Guide

Guide describing how to air-seal doors that are next to unconditioned spaces.

Flood-Resistant Raised-Slab Foundations

Guide

Guide describing ways to construct a raised-slab foundation to increase a home's resistance to floods.

Site Drainage Practices to Minimize Localized Flooding

Information Guide

Information guide describing steps that builders can take to reduce the likelihood of standing water and localized flooding around the foundation of a home during rainy conditions.

Design and Retrofit for Flood Protection

Information Guide

Information guide describing flood protection measures to minimize damage and increase structural resilience of homes during a flood.

Final Grade Slopes Away from Foundation

Guide

Guide describing how to properly grade a site so water will flow away from the foundation.