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Drainage techniques for slab-on-grade foundations

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Poor drainage conditions can enable water to pool around the home.

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Right - Basement slab with a capillary break of either gravel or a drainage mat.

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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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Spray foam extends down the foundation wall to the slab, which has been retrofitted by adding dimple plastic drainage mat and rigid foam insulation.

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Spray foam extends down the inside of the foundation wall to the uninsulated slab; because the wall lacked exterior perimeter drainage, the slab was cut and an interior footing drain was installed.

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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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Spray foam insulation extends down the foundation wall to the slab, which has been retrofitted by cutting the slab to install drainage mat against the wall and a new perimeter footing drain, along with rigid foam plastic above the slab.

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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 Insulation Installed over Existing Foundation Slabs

Guide

Guide describing how to insulate an existing slab floor by adding rigid foam insulation over the slab then installing a floating subfloor.

Insulating Crawl Space Floors in Existing Homes

Guide

Guide describing how to upgrade a crawlspace floor in an existing home by adding insulation.

Slab Edge Insulation

Guide

Guide describing how to insulate slabs on grade in climate zones 3 and higher.

Capillary Break Beneath Slab - Polyethylene Sheeting or Rigid Insulation over Aggregate or Sand and Geotextile Mat

Guide

Guide describing how to install a capillary break under a slab foundation using either polyethylene sheeting or rigid insulation installed over aggregate or over sand and geotextile matting.

Sump Pump Cover Gasket

Guide

Guide describing how to install an airtight cover on a sump pump in the basement or crawlspace of a home to minimize humidity in the home.

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.

Patio Slabs, Porch Slabs, Walkways, and Driveways Slope Away from House

Guide

Guide describing how to slope solid surfaces outside of a home so rainwater flows away from the home.

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.

Capillary Break at Crawlspace Floor - Polyethylene Sheeting under Concrete Slab

Guide

Guide describing how to install a capillary break to help manage moisture in foundations.

Exterior Edge Insulation for Existing Foundation Slabs

Guide

Guide describing how to install slab edge insulation when retrofitting existing slab-on-grade foundations.

Radon Fan

Guide

Guide describing how to install a radon mitigation fan to actively remove radon from the home.

Flood-Resistant Raised-Slab Foundations

Guide

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