Skip to main content

Adding Exterior Insulation when Re-Siding

Re-siding of an existing home presents an excellent opportunity to install continuous rigid insulation over the walls while the old siding is pulled off and before the new siding is installed. 

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.

Downloadable PDF Version
English

Preparation

The walls shall be inspected for any evidence of bulk water penetration, knob and tube wiring, or moisture or pest damage, and a list of any potential problems shall be provided to the homeowner before proceeding with the work so remediation can be fully addressed within the scope of the siding replacement.
Inspect the walls and note architectural features, window and door trim projections, hose bibs, light fixtures, and other features that may be impacted by the addition of exterior insulation.

Installation: Continuous Exterior Insulation

Existing wall cladding and trim shall be removed.
The wall sheathing shall be free of any protruding nail heads, screws, or irregularities to ensure a smooth surface for installing the air/water control membrane.
All exposed cracks and penetrations at sheathing, rim areas, and top and bottom plates shall be air sealed with sealant compatible with the surface.
If foam plastic insulation sheathing (FPIS) like XPS or foil-faced polyiso is used for the exterior rigid insulation, tape the foam with a compatible tape to serve as the air and water control layers. If other exterior insulation products are used, install a liquid-applied weather-resistant barrier product or house wrap with all of the seams taped.
Flashing for windows and doors shall be integrated with the WRB to protect the wall assembly from bulk moisture.
If the existing windows and doors are replaced and frames are replaced as well, new head, jamb, and sill flashing shall also be installed and properly integrated with the insulation and weather-resistant barrier layers.
Insulation shall be installed in accordance with the R-value specified for the wall assembly under the contract agreement for this work.
Furring strips, draining house wrap, or other spacing material shall be installed to provide an air gap behind lap siding, or brick or stone veneer. Wall cladding and trim shall be attached to the furring strips or through the air gap material to the studs. Where vinyl siding is used, the furring strips are not required.
Install new siding per manufacturers’ instructions.

Commissioning

A combustion safety test in accordance with ANSI/ACCA 12 QH Appendix A or RESNET Chapter 8 shall be performed if any natural draft combustion appliances (e.g., water heater, furnace) exist in the home to help ensure there is no back-drafting or spillage of combustion emissions when the home is made more airtight. Recommendations for remediation shall be made to the homeowner where combustion safety issues are identified.
Contractor installs rigid foam while residing a house

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:

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.

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.