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Polyethylene sheeting covers the aggregate and extends down and under the footing to provide a capillary break between the ground and the slab and monolithic footing

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Right - The existing basement slab is retrofitted by installing a dimple plastic drainage mat, rigid foam insulation, and a floating subfloor.

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Right - This poured concrete basement wall is insulated on the exterior and under the slab with rigid insulation; footing details include interior and exterior footing drain pipe.

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Wrong – Drain pipe has been cut and foundation penetration has not been properly sealed

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Right – Polyethylene sheeting is laid over aggregate and over footing to provide a capillary break between the ground and the slab and between the footing and the stem wall

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2021 IECC Climate Zone 1A: Flat Roof, Unvented, 2x6 Wall, Monolithic Slab on Grade (with notes)

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2021 IECC Climate Zone 2A: Flat Roof, Unvented, 2x6 Wall, Monolithic Slab on Grade (with notes)

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2021 IECC Climate Zone 2B: Flat Roof, Unvented, 2x6 Wall, Monolithic Slab on Grade (with notes)

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Exterior Insulation for Existing Foundation Walls

Guide

Guide describing how to insulate a new foundation wall or an existing foundation wall by adding rigid insulation to the exterior side.

IECC Climate Zone 1A: Unvented Attic with Spray foam at Roof Deck, 2x6 Wall-CMU Wall, Elevated Slab

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Install termite shields and use solid concrete or filled concrete block for the top of foundation walls to deter termites and other pests

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IECC Climate Zone 2A: Unvented Attic with Spray Foam at Roof Deck, 2x6 Wall/CMU Wall, Elevated Slab

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IECC Climate Zone 2A: Unvented Attic with Spray Foam at Roof Deck, 2x6 Wall/CMU Wall, Elevated Slab

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2021 IECC Climate Zone 2A: Unvented Attic with Spray Foam at Roof Deck, 2x6 Wall-CMU Wall, Elevated Slab

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Flood-Resistant Crawlspace Foundations

Guide

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

This home is heated with in-floor hydronic radiant heating tubes that were installed on top of the R-20 rigid foam under-slab insulation.

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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.

Rigid insulation and water control layers are installed on the exterior of a flat foundation wall; spray foam insulates the rim joist

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Right - Potential locations for basement insulation in new construction, slab insulation should always be underneath, with walls insulated (a) inside, (b) outside, (c) sandwiched inside, or (d) inside and outside of walls.

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Right – Two inches of rigid foam was installed on the ground before pouring the basement floor slab while precast, pre-insulated concrete panels comprise the basement walls.

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Pest protection measures include a termite shield under the rim joist and extending out on either side of the stem wall, insect screening under the furring air gap, and brick veneer to protect slab-edge insulation.

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An anchor side plate is used to connect the concrete foundation to the sill plate from the exterior as part of a seismic retrofit when the sill plate is not accessible from the interior of the home

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Right – The raised-slab, CMU block stem wall, above-grade walls, and roof of this house use flood damage-resistant materials, integrated water, vapor, and air control layers, and construction methods which promote good drainage and rapid drying

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Right – The raised-slab, poured-concrete stem wall, above-grade walls, and roof of this house use flood damage-resistant materials, integrated water, vapor, and air control layers, and construction methods which promote good drainage and rapid drying

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Right – The raised-slab, brick-and-block stem wall, above-grade walls, and roof of this house use flood damage-resistant materials, integrated water, vapor, and air control layers, and construction methods which promote good drainage and rapid drying

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Rigid Foam Board Interior Insulation for Existing Foundation Walls

Guide

Guide describing how to insulate closed crawlspace walls and band joist areas with rigid foam board insulation.

No Vapor Retarders on Interior Side of Air-Permeable Foundation Insulation

Guide

Vapor retarder plastic should not be installed over fibrous insulation on basement or crawlspace walls; rigid foam or spray foam should be installed directly against the concrete, behind the blanket insulation.

Right – The foundation of this ICF home was constructed of ICFs that were set in place on a gravel bed, then 3.5 inches (R-36) of closed-cell spray foam was sprayed directly onto the gravel, providing an effective air, vapor, and thermal barrier.

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Increase Seismic Resistance and Thermal Performance of Basement, Crawl Space, and Crawl Space with Cripple Wall Foundations

Guide

Guide describing different options for providing seismic and thermal resistance for homes with basement foundations, crawlspace foundations, or crawlspace foundations with a "cripple" wall.

Good water management practices like sloping grade away from house, and installing gutters, perimeter drain pipe, a capillary break, and free-draining soils or drainage mat protect the foundation from water saturation.

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