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Evaluation of Crawlspace Retrofits in Multifamily Buildings

Reference

Report analyzing results in crawlspace retrofits in multifamily buildings.

Moisture Control for Residential Buildings

Reference

Report providing extensive guidance on controlling moisture in building envelopes through proper selection and installation on air, water, thermal, and vapor barriers.

New Light in Crawlspaces, BSI-009

Reference

Building science insight into crawlspaces.

Moisture problems must be dealt with before sealing and insulating a crawlspace

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Right – Foundation drainage mat was installed over the waterproof membrane that covers the sealed crawlspace window

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Flood vents allow floodwaters to enter and exit the crawlspace without causing hydrostatic pressure differences

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Right – A sump pump with a perforated sump pit was installed in the crawlspace slab to reduce water accumulation under the slab

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Provide a continuous air barrier from the rigid foam below the crawlspace floor joists to the rim joist to the exterior wall above

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An exhaust fan pulls damp air out of a retrofitted sealed crawlspace while drawing in dry air from the living space

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Before sealing and insulating the crawlspace, the windows were sealed, the window wells backfilled, and sumps pumps were installed that discharged to the gutter downspouts

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Wrong – This vented crawlspace has standing water because steps were not taken to address site conditions that led to bulk water flow into the crawlspace

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Wrong – A poorly sealed window and window well allow bulk water to enter the crawlspace from ground that slopes toward the structure

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Water-proof materials cover the exterior side of crawlspace windows in a crawlspace retrofit, while foil-faced rigid foams seals and insulates the inside face of the openings

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Right – Foil-faced insulation was added after the crawlspace was dried and sealed by diverting water runoff, sealing off crawlspace windows and vents, and adding sump pumps and exhaust fan ventilation

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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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Right – This crawlspace window was completely sealed off on the inside and outside with air barrier and water-proof materials and the window well was filled in to an above-grade height to prevent bulk water from entering the crawlspace

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Radon vertical ventilation pipe system – crawlspace construction

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Understanding Basements, BSD-103

Reference

Information sheet with methods for constructing or retrofitting basements to reduce moisture issues.

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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Comprehensive water management features include a capillary break (≥ 6-mil polyethylene sheeting) at all crawlspace floors

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Crawlspaces – Either In or Out, BSI-115

Reference

Article discussing whether or not to seal and insulate crawlspaces.

Taping polyethylene sheeting at interior pier footings

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Drain or Sump Pump Installed in Basements or Crawlspaces

Guide

Guide describing installation of sump pumps in the basement or crawlspace of a home.

Conditioned Crawl Space Construction, Performance and Codes, BA-0401

Reference

Report outlining how conditioned crawlspaces perform better than vented crawlspaces in terms of safety, health, comfort, durability and energy consumption.

Comprehensive above-grade water management details for a crawlspace foundation include a capillary break over the crawlspace floor, slope the surface grade away, installing gutters that slope away, and capillary break under sill plate.

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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.

Evaluation of Crawlspace Retrofits in Multifamily Buildings

Moisture Control for Residential Buildings

New Light in Crawlspaces, BSI-009

Moisture problems must be dealt with before sealing and insulating a crawlspace

Right – Foundation drainage mat was installed over the waterproof membrane that covers the sealed crawlspace window

Flood vents allow floodwaters to enter and exit the crawlspace without causing hydrostatic pressure differences

Right – A sump pump with a perforated sump pit was installed in the crawlspace slab to reduce water accumulation under the slab

Provide a continuous air barrier from the rigid foam below the crawlspace floor joists to the rim joist to the exterior wall above

An exhaust fan pulls damp air out of a retrofitted sealed crawlspace while drawing in dry air from the living space

Before sealing and insulating the crawlspace, the windows were sealed, the window wells backfilled, and sumps pumps were installed that discharged to the gutter downspouts

Wrong – This vented crawlspace has standing water because steps were not taken to address site conditions that led to bulk water flow into the crawlspace

Wrong – A poorly sealed window and window well allow bulk water to enter the crawlspace from ground that slopes toward the structure

Water-proof materials cover the exterior side of crawlspace windows in a crawlspace retrofit, while foil-faced rigid foams seals and insulates the inside face of the openings

Right – Foil-faced insulation was added after the crawlspace was dried and sealed by diverting water runoff, sealing off crawlspace windows and vents, and adding sump pumps and exhaust fan ventilation

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

Right – This crawlspace window was completely sealed off on the inside and outside with air barrier and water-proof materials and the window well was filled in to an above-grade height to prevent bulk water from entering the crawlspace

Radon vertical ventilation pipe system – crawlspace construction

Understanding Basements, BSD-103

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

Comprehensive water management features include a capillary break (≥ 6-mil polyethylene sheeting) at all crawlspace floors

Crawlspaces – Either In or Out, BSI-115

Taping polyethylene sheeting at interior pier footings

Drain or Sump Pump Installed in Basements or Crawlspaces

Conditioned Crawl Space Construction, Performance and Codes, BA-0401

Comprehensive above-grade water management details for a crawlspace foundation include a capillary break over the crawlspace floor, slope the surface grade away, installing gutters that slope away, and capillary break under sill plate.

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

Retrofit Existing Crawl Space Foundations with Cripple Walls to Increase Seismic Resistance and Thermal Performance

Flood-Resistant Crawlspace Foundations

Radon Fan

Vertical Radon Ventilation Pipe