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Insulating Crawl Space Floors in Existing Homes

Guide

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

Water Managed Roof – Re-roofing and Adding Insulation over a Flat Roof

Guide

Guide describing an approach to re-roofing an existing flat roof to improve thermal, water, and air control performance.

Class I Vapor Retarders Not Installed in Above-Grade Walls in Warm-Humid Climate

Guide

Guide describing vapor retarder permeability, insulation interaction, and example construction in a hot-humid climate.

When condensation forms on the interior side of wall sheathing and is not able to dry out, it can lead to mold growth and rotting of wall sheathing and framing

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Smart Vapor Barrier - CertainTeed Dryright-vs-Kraft-Faced Insulation

Reference

Report describing a comparison of hydrothermal performances of DryRightTM fiberglass batts and kraft-faced fiberglass batts in a south facing wall assembly with a moisture storage cladding material.

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.

Water Managed Roof – Re-roofing and Adding Insulation Over a Sloped Roof

Guide

Guide describing how to re-roof an existing home with a sloped roof and add insulation above the roof deck.

Step and Kick-Out Flashing at Roof-Wall Intersections

Guide

Guide describing how to install step and kick-out flashing where walls meet roofs.

Hygric Redistribution in Insulated Assemblies: Retrofitting Residential Envelopes Without Creating Moisture Issues

Reference

Report exploring four questions to determine the level of risk associated with adding drained exterior insulation to the exterior of an existing home during an energy retrofit.

Polyethylene is being attached to the crawlspace floor and walls with plywood furring strips

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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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Terminate 4" tape with 2" wide tape placing tape offset high on the joint, 2/3 of the tape should be adhered to the sheet of insulation

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Flashing of Roof-Wall Intersections in Existing Homes

Guide

Guide describing how to install and properly integrate flashing at the intersection of the wall and roof on an existing home.

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

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A continuous layer of polyethylene covers the crawlspace floor and is attached to the wall with wood nailing strips

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Right – The flashing is properly installed to create a complete drainage system with continuous rigid insulation sheathing/siding

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Wrong - Class I vapor retarder over framed basement walls can cause condensation, mold, and rotting because plastic prevents drying to the inside; the outside should have waterproofing and vertical drainage, and the framing should be spaced from the wall.

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Right - Below-grade concrete has been properly sealed against moisture and is now having insulation installed.

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Right – The insulated concrete forms that are below-grade have a damp-proof coating to prevent moisture seeping into the foundation

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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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Insulating Crawl Space Floors in Existing Homes

Water Managed Roof – Re-roofing and Adding Insulation over a Flat Roof

Class I Vapor Retarders Not Installed in Above-Grade Walls in Warm-Humid Climate

When condensation forms on the interior side of wall sheathing and is not able to dry out, it can lead to mold growth and rotting of wall sheathing and framing

Smart Vapor Barrier - CertainTeed Dryright-vs-Kraft-Faced Insulation

Rigid Foam Insulation Installed over Existing Foundation Slabs

Water Managed Roof – Re-roofing and Adding Insulation Over a Sloped Roof

Step and Kick-Out Flashing at Roof-Wall Intersections

Hygric Redistribution in Insulated Assemblies: Retrofitting Residential Envelopes Without Creating Moisture Issues

Polyethylene is being attached to the crawlspace floor and walls with plywood furring strips

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.

Technology Solutions Case Study: Hygrothermal Performance of a Double-Stud Cellulose Wall

Proper flashing around windows is especially important when the rigid foam serves as the drainage plane in the wall

Polyethylene completely covers the floor of this crawlspace and is attached to the walls and piers as well

Clean taping areas and install 3" tape on vertical joint of upper insulation overlapping the horizontal joint

Flashing at Bottom of Exterior Walls

Wrong – The insulated concrete forms at the foundation do not have a damp-proof coating

Right – Polyethylene sheeting vapor barrier is installed and sealed to the crawlspace walls with mastic

Tape the joint between the top insulation sheet and the Z-flashing with 2" wide tape to improve air tightness

ICF bricks are stacked to form hollow walls that are reinforced with steel rebar before the concrete is poured in

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

Terminate 4" tape with 2" wide tape placing tape offset high on the joint, 2/3 of the tape should be adhered to the sheet of insulation

Flashing of Roof-Wall Intersections in Existing Homes

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

A continuous layer of polyethylene covers the crawlspace floor and is attached to the wall with wood nailing strips

Right – The flashing is properly installed to create a complete drainage system with continuous rigid insulation sheathing/siding

Wrong - Class I vapor retarder over framed basement walls can cause condensation, mold, and rotting because plastic prevents drying to the inside; the outside should have waterproofing and vertical drainage, and the framing should be spaced from the wall.

Right - Below-grade concrete has been properly sealed against moisture and is now having insulation installed.

Right – The insulated concrete forms that are below-grade have a damp-proof coating to prevent moisture seeping into the foundation

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