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Spray Foam Interior Insulation for Existing Foundation Walls

Guide describing how to insulate an existing foundation wall by adding spray foam insulation to the interior side of the wall.

No Vapor Retarders on Interior Side of Air-Permeable Foundation Insulation

Vapor retarder plastic should not be installed over fibrous insulation on basement or crawlspace walls unless rigid foam or spray foam is installed directly against the concrete, behind the blanket insulation.

The below-grade wall assembly includes dampproofing, draining details, and insulation.

Publication Date

Tue, 05/01/2012 - 12:00

The seams of the rigid insulation are not taped and it will not provide a complete capillary break

Publication Date

Tue, 02/01/2011 - 12:00

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

Publication Date

Tue, 02/01/2011 - 12:00

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

Publication Date

Tue, 02/01/2011 - 12:00

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

Publication Date

Tue, 02/01/2011 - 12:00

Easy access

Publication Date

Tue, 05/01/2012 - 12:00

Concrete Solutions, BSI-118

Author(s)

Lstiburek Joseph W

Organization(s)

Building Science Corporation,

BSC

Publication Date

October, 2020

Report covering insulating crawlspaces.

Builders Challenge High Performance Builder Spotlight: David Weekley Homes, Houston, Texas

Author(s)

Pacific Northwest National Laboratory

Organization(s)

PNNL

Publication Date

December, 2009

Case study describing new home construction in the hot-humid climate, optimizing thermal enclosure, HVAC, water heating and lighting measures.

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.

Publication Date

Thu, 03/01/2012 - 12:00

Water intrusion

Pouring the slab

Damp-Proof Exterior Surface of Below-Grade Walls

Guide describing how to apply water management strategies to below grade walls.

There is no polyethylene sheeting installed in the crawlspace

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

Publication Date

Tue, 02/01/2011 - 12:00

Wrong – The polyethylene sheeting vapor barrier is not attached to the piers with mechanical fasteners

Publication Date

Tue, 02/01/2011 - 12:00

Efficient Earth-Sheltered Homes

Author(s)

U.S. Department of Energy

Organization(s)

DOE

Publication Date

January, 2022

Webpage from U.S. Department of Energy describing using Earth-Sheltered home building techniques in hot climate zones.

Keeping Homes and Cities Cool in Extreme Heat

Author(s)

Kyle Mittan

Organization(s)

University of Arizona

Publication Date

June, 2021

Article from University of Arizona on keeping homes cool during extreme heat, both personal and system changes.

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

Publication Date

Thu, 02/01/2018 - 12:00

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.

Publication Date

Thu, 03/01/2012 - 12:00

Spray Foam Interior Insulation for Existing Foundation Walls

No Vapor Retarders on Interior Side of Air-Permeable Foundation Insulation

The below-grade wall assembly includes dampproofing, draining details, and insulation.

The seams of the rigid insulation are not taped and it will not provide a complete capillary break

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

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

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

Easy access

Concrete Solutions, BSI-118

Builders Challenge High Performance Builder Spotlight: David Weekley Homes, Houston, Texas

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.

Water intrusion

Pouring the slab

Damp-Proof Exterior Surface of Below-Grade Walls

There is no polyethylene sheeting installed in the crawlspace

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

Wrong – The polyethylene sheeting vapor barrier is not attached to the piers with mechanical fasteners

Efficient Earth-Sheltered Homes

Keeping Homes and Cities Cool in Extreme Heat

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

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.

Capillary Break at Crawlspace Floors - Polyethylene Lapped Up Walls and Piers or Secured in the Ground

Capillary Break at Crawlspace Floor - Polyethylene Sheeting under Concrete Slab

Design and Retrofit for Flood Protection

Footing Drain Pipe

Final Grade Slopes Away from Foundation

Roof Anchor System for Solar Panels