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Foundation wall exterior board insulation with above-grade wall insulation

CAD File

Air Sealed, Insulated Basements

Guide

Guide describing how to insulate a basement to improve the overall thermal performance of the building and provide more dry, usable conditioned space for home occupants and HVAC equipment.

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 - Section view showing how to air-seal and insulate a basement wall with perforated blanket insulation by installing it over air-sealed rigid insulation board to reduce condensation risk in the fiberglass blanket.

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Wrong - Moisture from within the basement foundation wall can migrate into the insulation cavity in a conventional blanket insulation installation.

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Insulating a crawlspace foundation with “cripple wall” in warm climates; in Climate Zones 5+ replace the foil- or plastic-faced fiberglass batt/roll insulation with impermeable rigid insulation or closed-cell spray polyurethane foam

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Right - A continuous layer of rigid foam insulation is installed against the foundation, and the perforated fiberglass insulation blanket is installed over that and covered with a semipermeable facing.

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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.

To reduce the risk of condensation on the interior of the roof sheathing in cold weather, the ratio of exterior (above-deck) insulation must be increased as a percent of total attic insulation as outside temperature decreases

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Vented crawlspace foundation insulated at floor joist with rigid foam.

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Exterior XPS basement insulation is correctly installed to completely cover the foundation wall

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New Code Options for Insulating, Sealing, and Controlling Moisture in Unvented Attics in Residential Buildings

Presentation

Webinar explaining new code options for insulating, sealing, and controlling moisture in unvented attics in residential buildings.

Technology Solutions Case Study: Field Testing an Unvented Roof with Fibrous Insulation and Tiles

Case Study

Case study describing field testing of an unvented roof with fibrous insulation and tiles.

Right - This concrete basement wall has exterior rigid insulation and comprehensive moisture management details.

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Technology Solutions Case Study: Retrofit Measures for Embedded Wood Members in Insulated Mass Masonry Walls

Case Study

Case study describing retrofit measures for embedded wood members in insulated mass masonry walls.

R-5 XPS rigid foam exterior sheathing provides an air seal, moisture barrier, and additional insulation value.

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Moisture-resistant rigid foam insulation was installed to provide a continuous air and thermal barrier behind the tub-shower insert.

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Wrong – A clothes dryer that vents to the crawlspace can contribute moisture to the crawlspace; this can result in damp, molding, and rotting insulation

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Right - the vapor barrier is extended up the sides of the piers in this crawlspace, which is sealed and insulated to house the HVAC ducts.

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This farmhouse was retrofit by removing the existing siding and adding taped insulated sheathing and battens before installing new siding

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Because the above-grade potions of the wall lack exterior insulation, condensation and even ice form during cold winter conditions

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The Perfect Wall includes water, air, thermal, and vapor layers with continuous insulation exterior of the sheathing to reduce the condensation potential in the wall.

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Masonry wall interior retrofit with fluid-applied water control layer and wood-framed wall with cavity insulation (climate zones 1-4 only)

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Right – The air- and water-barrier material lining the shower stall is mastic sealed to prevent leakage and rigid foam insulation is installed on the floor of the shower.

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Stucco is installed over rigid insulation, which is installed over a drainage plane consisting of a drainage gap and building wrap layer over the sheathing

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Wrong - Air leakage from the conditioned space to the basement foundation wall can lead to condensation or moisture issues in a conventional blanket insulation installation.

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On top of the ice-and-water shield, the builder installed horizontal beams that were raised 6 inches off the deck to allow room for spray foam insulation.

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Foil-faced rigid foam and spray foam can be used to insulate a basement on the interior; use good moisture management techniques to keep the basement dry

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Construction Guide - Next Generation High Performance Walls in Climate Zones 3-5, Part II: 2x4 Walls with 1” - 1.5” Exterior Insulative Sheathing

Reference

The Guide addresses walls constructed with 2x4 wood frame studs, wood structural panel (WSP) sheathing as wall bracing and added backing for foam sheathing, a layer of rigid foam sheathing insulation up to 1.5 in. thick over the WSP, and a cladding system installed over the foam sheathing in low...

Exterior fiberglass insulation on this new home was (incorrectly) cut to terminate below-grade after backfill, which will expose the above-grade portions of the foundation wall to cold temperatures

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