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Masonry Wall Insulation

Installed correctly, masonry wall insulation can cut your utility bills, make your home more comfortable, and increase its value.

Older homes without effective wall insulation allow excessive heat loss in winter and heat gain in summer. Insulating walls is a highly effective way to improve your home’s performance. Adding wall insulation can reduce your heating and cooling bills, improve comfort, reduce drafts, and help your home meet increasing performance expectations. However, insulating masonry walls involves unique challenges. The traditional “drill and fill” approach of drilling through the exterior siding will not work if the exterior is masonry brick or concrete. Options for insulating from the exterior include covering the existing brick with rigid foam or removing existing siding from concrete block, then installing rigid foam and new siding. Alternatively, drill and fill can be used on the interior if a cavity wall exists, or rigid foam or an insulated cavity wall can be constructed over an existing concrete block wall.

Checklist

This U.S. Department of Energy checklist includes important specifications that can contribute to a complete and quality installation. All work shall comply with these specifications, all relevant codes and standards, and all manufacturer installation instructions. The contractor shall check each box on the checklist below and sign and date at the bottom to certify the work is completed.

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Preparation


The walls shall be inspected for any evidence of damage from bulk water intrusion, moisture, or pests. A list of any potential problems shall be provided to the homeowner before proceeding with wall insulation so remediation can be fully addressed as necessary, including improving exterior flashing details as needed, before starting the work.

Installation: Option 1 - Exterior Insulation with Rigid Foam Board Insulation


Rigid insulation shall be attached to the exterior side of the existing masonry using fasteners or glue, as recommended by the manufacturer. All seams shall be tight fitting and the insulation shall completely cover the masonry without any gaps or voids, and all joints shall be fully sealed with tape, spray foam, or caulk.

New window and door flashing shall be installed including pan flashing at the sill.

The door and window jambs and sills shall be extended if needed, based on the thickness of the foam. This may require removal and re-installation of the windows and doors.

Furring strips or spacers should be installed over the rigid foam to provide a drainage and ventilation space between the foam and the new siding.

Installation: Option 2 - Interior Insulation with Spray Foam and Batt Insulation


A steel stud wall shall be constructed 2 inches away from the masonry wall.

Window sills and door jambs shall be extended and electrical boxes relocated as needed for increased wall depth.

Two to 4 inches of high-density closed-cell or medium-density open-cell foam shall be sprayed directly onto the masonry behind the studs to completely cover the wall surface.

Once the foam is in place, fibrous insulation shall be installed in the stud cavities for any additional R-value specified for the wall assembly under the contract agreement for this work. Install fire stop as necessary above foam cavity insulation.

Finishing material (e.g., drywall) shall be attached to the studs. No vinyl wallpaper or other Class I vapor retarder shall be used.

Installation: Option 3 - Interior Rigid Foam Board Insulation


Rigid foam insulation boards with an R-value that meets or exceeds the 2012 International Energy Conservation Code prescriptive requirement for the home’s location shall be attached to the interior of the wall with construction adhesive applied in a serpentine pattern. When using two layers of foam, the seams shall be staggered.

The rigid foam boards shall completely cover all exposed interior wall surfaces with no air gap between them and shall be fully in contact with the wall.

Seams shall be sealed with caulk, foam, mastic, or flashing tape specified by the rigid foam insulation manufacturer.

Furring strips shall be installed to create a nailing surface for the drywall. Install fire stop as necessary above rigid foam insulation.

No vinyl wallpaper or any other kind of Class I vapor retarder shall be used on the inside face of the wall.
Masonry Wall Insulation

Tips to Sell Quality Installed Home Improvements

Home Improvement Expert is a valuable tool for organizations committed to quality installed work. The following tips help optimize the value of this tool when selling home improvements:

Trust Matters: Inform homeowners how your work conforms to this world-class expert guidance. Recommend they visit the DOE website as evidence these are indeed official best practices.

Knowledge Matters: Take advantage of the Building America Solution Center as a resource for becoming an expert on these projects.

Clarity Matters: Tell prospective clients to contrast your expert-recommended best practices with other contractors.

Value Matters: Advise prospective clients to insist other bids also include these checklists to ensure equivalent quality work.

Message Matters: Showcase on your website and marketing materials that your company uses the highest quality best practices specified on HIE Checklists.

Experiences Matter: Provide visual evidence contrasting the difference between poor and high quality work such as infrared images; pre- and post-energy bills; short and long warranties; and simple charts and graphics depicting performance advantages.

Related Guides

Guide:

Pre-Retrofit Assessment of Walls, Windows, and Doors

Description
Information guide describing things to consider before retrofitting walls, windows, and doors, including wiring, moisture protection, and lead paint.
Guide:

Rigid Foam Insulation for Existing Exterior Walls

Description
Guide describing how to apply an air control layer directly over existing wall sheathing and cover with two layers of insulating sheathing held in place by vertical furring strips.
Guide:

Spray Foam Insulation for Cavities of Existing Exterior Walls

Description
Guide describing how to insulate the wall cavities of an existing home with spray foam.

Disclaimer

This content is a work created with funding provided by the United States Department of Energy under Contract no DE-AC05-076RL01830 for the operation of Pacific Northwest National Laboratory. The information and guidance provided by Pacific Northwest National Laboratory (PNNL) in the content are intended solely for educational purposes only and do not constitute formal training or certification. It is provided with the explicit understanding that neither the United States Government nor the United States Department of Energy, nor the Contractor, nor any or their employees, nor any jurisdiction or organization that has cooperated in the development of these materials, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness or any information, apparatus, product, software, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof, or Battelle Memorial Institute. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof. Viewers assumes full responsibility for all actions that they may take from information provided in this content including ensuring the safety, code compliance, and proper functionality of any products they choose to install. Installation and use of such products should be performed in accordance with local regulations and manufacturer instructions.