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This concrete masonry unit (CMU) wall is insulated with rigid insulation on the exterior side of the concrete block

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This concrete masonry unit (CMU) wall is insulated with rigid insulation on the exterior side of the concrete block

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Rigid Insulation Over Aggregate

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Ducts Buried in Attic Insulation and Encapsulated

Guide

Guide describing approaches to burying and encapsulating ducts in unconditioned attics to increase the overall R-value of duct insulation.

High-Performance Slab-on-Grade Foundation Insulation Retrofits

Reference

Report assessing slab-on-grade foundation insulation energy savings.

Right – The basement of this cold-climate home is insulated along interior walls with 2 inches of foil-faced rigid foam; finished basement walls also have a 2x4 interior wall insulated with R-19 blown-in fiberglass insulation and a poly vapor barrier.

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Typical R-values and Vapor Retarder Classifications for Common Insulation Materials

Information Guide

Information guide providing R-Values and vapor retarder classifications for common insulation materials.

Technology Solutions Case Study: Moisture Durability of Vapor Permeable Insulating Sheathing

Case Study

Case study describing research about using exterior, vapor permeable insulation of retrofit walls with vapor permeable cavity insulation.

Walls in cold climates with a polyethylene vapor barrier interior of the wall cavity should have either no exterior insulation or a vapor-open continuous insulation like mineral wool that allows drying to the exterior

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Right – Prepoured foundation panels with integrated insulation and vapor barrier are installed in place.

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Wrong - Duct insulation and vapor barrier do not cover all of the flex duct.

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Right - This rigid insulation is correctly installed in a level layer over aggregate; the seams will be taped

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The builder’s crews spray foam directly onto the ground to provide a vapor barrier and insulation layer under the slab.

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Rigid foam insulation can serve as the drainage plane when all seams are taped. Furring strips provide an air gap behind the cladding.

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Wrong - The fiberglass blanket insulation has no perforated vapor retarder, does not cover the entire basement wall, is not sealed at the edges, and is not installed over rigid foam.

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Vapor-permeable mineral wool insulation is installed on the exterior side of the sill beam during an exterior wall retrofit to allow the sill beam to dry to the outside

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Walls in cold climates with a Class 3 vapor retarder (latex paint) and a vapor-open continuous insulation like mineral wool allow drying to the interior or the exterior

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Masonry wall interior retrofit with parge coat, fluid-applied water control layer, rigid mineral wool, wood-framed wall with cavity insulation, smart vapor barrier, and wood or metal service cavity

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Right – The raised slab foundation has a 3-ft stem wall of filled concrete block, then is back-filled with compacted dirt and crushed rock, then insulated with 1” rigid foam covered with taped vapor barrier, under a floor slab.

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This Texas homes uses a slab foundation including a 4-in.-thick post-tensioned monolithic slab with turned-down edges poured over a 6-mil polyethylene vapor barrier and capillary break; slab edge insulation is not used due to termite risk.

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Condensation Control for Walls in Cold Weather

Guide

Guide describing ways to construct wall assemblies in cold climates to minimize the likelihood of condensation formation inside the walls.

Passive House Underslab Foam & Vapor Barrier: Karuna Video #6

Video

Video describing the under slab and vapor barrier used on a passive house.

Building Code Training - Residential Thermal Envelope - Air Sealing

Presentation

Presentation describing the Georgia State Minimum Standard Energy Code air barrier requirements, envelope concepts including air flow and thermal properties, and common missed insulation and air-sealing opportunities.

Wrong - Polyethylene sheeting should be lapped up sides of walls and pillars and taped

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Right-Polyethylene sheeting is correctly installed over aggregate and taped to pillars and foundation wall

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Right – Workers pour the concrete for the basement floor slab over a vapor barrier installed over rigid foam.

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Polyethylene Over Aggregate

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The Larsen-truss 9-inch wall cavities were covered with a smart vapor membrane that was fastened to the trusses with furring strips, which also provide an air gap behind the wood siding; each truss cavity is then filled with blown cellulose.

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Flow-Through Assemblies, BSI-091

Reference

Article discussing flow-through assemblies of walls.

The “institutional” perfect wall works in all climate zones; water, air, vapor, and thermal control layers are exterior of the sheathing, assembly allows drying to interior and exterior

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