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Pre-Retrofit Assessment of Walls, Windows, and Doors

Replacing windows and doors, and re-siding walls are common renovation projects. The first step in developing a plan for upgrading walls, windows, and doors is to perform a thorough visual evaluation of both exterior and interior conditions. The Existing Homes Tool provides links to several guides on air sealing, insulating, and controlling moisture in and around walls, windows, and doors. This inspection must be based on federal, state, and local regulations and carried out by a licensed or certified contractor. See the section below on Potential Stop-Work Conditions for a summary of important health and safety conditions to look for. The following sections provide greater detail on these and other conditions.

Potential Stop-Work Conditions

Figure 1 summarizes potential stop-work conditions and the remediation actions needed for each of these conditions. If any of the following items are found during the assessment, they must be dealt with before proceeding with work, or in some cases they can be incorporated into the project. Additional information on these conditions and others follows the figure.

Potential Stop Work Conditions when Renovating Windows, Doors, and Walls
Wiring and Electrical System

Assessing the current electrical system is one of the first steps in planning a wall project. A qualified electrician might need to be consulted if there is exposed or damaged wiring presenting a risk of shock or electrocution. Ensure that the location of wiring is taken into account before drilling into the walls.

Combustion Appliances

Air-sealing activities could impact combustion appliances in the home, such as furnaces or water heaters. See the assessment guide Pre-Retrofit Assessment of Combustion Appliances for more information. If combustion appliances are located in the home, verify that carbon monoxide alarms complying with UL 2034 are installed within the home in close proximity to the combustion appliances and outside each separate sleeping area.

Mold and Structural Integrity

Finding some traces of mold or mildew is common around windows where condensation forms or where there are air and water leaks. This mold is typically accessible for cleanup. Mold forming on cold spots on walls may also be the result of condensation on walls. See the list of control strategies listed under “Moisture” below. Extensive surface mold or fungal growth will require a certified mold remediation expert to conduct an inspection and determine an appropriate remediation protocol to clean all the components before work can proceed. Structural repairs or replacement of windows or doors will be necessary if there is extensive damage or wood rot.


Exposure to asbestos increases a person’s risk of developing lung disease. Vermiculite insulation inside wall cavities may contain asbestos. Siding and adhesives may also contain asbestos. Recommended protocols to identify and mitigate asbestos were developed by the U.S. Environmental Protection Agency and can be found in the document Healthy Indoor Environment Protocols for Home Energy Upgrades. More information is also provided in the guide “Pre-Retrofit Assessment of Hazardous Materials” and on the EPA’s Asbestos website.


In homes built before 1978 assume that paint is lead based. Any work being completed on the window systems should follow all state and federal laws for handling hazardous materials. Follow the most current version of the EPA’s Lead-Based Paint Renovation, Repair, and Painting Rule


Window and Door Sills

These components have heavy exposure to both direct rain and water running down walls, doors, and windows. Inspect these components for damage to determine if repair or replacement should be part of the project. See the guides on managing moisture in existing windows and doors in the Existing Homes Tool.

Roof Drainage

Inspect the roof’s bulk water discharge strategy, including all gutters and downspouts, to ensure bulk water runoff is not allowed to run onto walls, windows, and doors. Use sidewall and kick-out flashing to divert water runoff away from walls and into gutters. Pay particular attention to roof areas that run perpendicular to walls. Downspouts should discharge directly into drains that are directed to a storm sewer system, retention pond, daylighting if the land topography permits, or dry wells. If gutters are not present, they should be recommended to occupants.


Evaluate the grading around the perimeter of the house. Ideally, the ground should slope a minimum of 5% away from the foundation walls for at least the first 10 feet to direct groundwater away from the structure. If proper slope away from the foundation cannot be established because of the home’s elevation and surrounding grade, a surface drainage system (“grade gutter”) should be installed. This system collects water and diverts it away from the foundation. See the guides on managing moisture in existing site, foundations and crawlspaces linked in the Existing Homes Tool.


Turn on all sprinklers installed near the foundation to observe their flow pattern. The sprinklers must be positioned so they do not subject the windows, walls, doors, foundation, or its immediate vicinity to water.


When storm windows are installed, homes often become more prone to condensation. Condensation is caused by relatively warm moist air coming into contact with relatively cool storm windows. Prevent condensation by air sealing the enclosure around the window to block the flow of conditioned air. Moist air may also be the result of moisture-generating activity, such as cooking, leaky dryer vents, or showers. Exhaust fans or other forms of ventilation may be needed to remove moist air. Exhaust and dryer vents may need to be inspected and repaired.  Bare earth in crawlspaces may also be a source of moisture. Cover earthen floors in basements and crawlspaces with sealed vapor barriers, cover sump pump crocks with a gasketed lid, and take other steps to ensure proper crawlspace design as described in the guide Pre-Retrofit Assessment of Crawlspaces and Basements. Remove unvented combustion space heaters and ensure fireplaces are properly ventilated as these are sources of moisture and hazardous combustion gases. Install dehumidifiers if needed.


Animal Infestation: In some cases, walls that enclose crawlspaces or that have air or dryer vents or other penetrations that have been left unattended or neglected can harbor wild animals. Recognizing the exterior details that allow entry and exit of pests through the foundation, as well as the signs of animal or insect activity, will help prepare the inspector. Depending on the severity, the local animal control agency or exterminators might need to assist in removing any unwanted animals.

Termites and Carpenter Ants: Termites and carpenter ants are known to thrive in dark, damp places that have a readily available food source of wet wood nearby. Inspect the foundation walls and framing for signs of these pests before moving forward. Any observed signs will then require a more in-depth inspection and treatment by a pest control professional. Applying a coat of light-colored paint over the 3-inch pest control inspection gap at the top of the interior of foundation walls will facilitate pest inspections.

Code Considerations

It is imperative to check with local code authorities prior to the installation of any insulation in closed crawlspaces, basements, and band joist areas to ensure that all local code requirements are met, such as the R-value of insulation, fire and combustion safety requirements, pest inspection requirements, and radon mitigation requirements.


During any enclosure air-sealing activities, follow safe work practices to minimize any effects from sealants or adhesive fumes on workers’ health. See the U.S. Department of Energy’s Standard Work Specifications for more information about worker safety related to wall retrofits.

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References and Resources*

  1. Author(s): U.S. Environmental Protection Agency
    Organization(s): EPA
    Publication Date: July, 2017

    EPA's website about asbestos.

  2. Author(s): U.S. Environmental Protection Agency
    Organization(s): EPA
    Publication Date: December, 2014

    This publication provides a set of best practices for improving indoor air quality in conjunction with energy upgrade work in homes.

  3. Author(s): U.S. Environmental Protection Agency
    Organization(s): EPA
    Publication Date: June, 2010

    EPA’s 2008 Lead-Based Paint Renovation, Repair and Painting (RRP) Rule (as amended in 2010 and 2011), aims to protect the public from lead-based paint hazards associated with renovation, repair and painting activities.

Last Updated: Wednesday, July 19, 2017

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