Stucco Inspections

Minnesota Stucco Testing


Stucco evaluations are performed on both residentiastucco_inspectionl and commercial properties. Each investigation should address common construction deficiencies and possible mechanisms for moisture intrusion. Stucco inspections should be organized around three general methods, each of which may be performed with additional services such as architectural, petrographic, or engineering reports

1. Inspection with Moisture Testing and Infrared Analysis – Visual inspection couples with moisture survey provides a good indication of water damage to perimeter wall sheathing, framing, and windows. Visual inspection and infrared analysis evaluates subtle signs of water damage, including the appearance of the stucco itself as well as visible characteristics of flashing, grading, and stucco installation. Infrared analysis offers a non-destructive means for assessing the entire building envelope. Moisture surveys are then performed using electronic meters that probe interior or exterior surfaces of wall sheathing. Visual inspection with moisture survey is the most common approach to stucco inspection. Still, when water damage is confirmed, the precise mechanisms for intrusion must be determined by more invasive procedures.

Applications: routine monitoring, real estate inspections, and building underwriting.

2. Inspection with Moisture Testing, Infrared Analysis, and Invasive Investigation – This approach provides a more definitive assessment of potential stucco problems and mechanisms for water intrusion. Small (12”x12”) sections of stucco are removed from strategic locations. Physical characteristics of the stucco, lath, weather-resistive membrane, and sheathing are then evaluated and compared to recognized building standards. Invasive investigations also facilitate inspection of flashing details and suspected structural damages.

Applications: insurance claims, properties with impending warranty expirations, litigation support, determining scope of remediation, and further due diligence for real estate transfers.

3. Complete Evaluation with Petrographic Analysis – This method represents the most definitive approach to stucco inspection and is typically recommended for structures involving undocumented stucco systems or in case of suspected stucco failure. All aspects of the stucco system and building envelope are evaluated. Stucco samples are submitted to an independent laboratory for petrographic analysis, which provides further detail of physical characteristics such as types of aggregates and binders, layer thickness, and layer composition. If necessary, complete physical and chemical testing can include volumetric analysis, bond strength testing, permeability testing, and curing properties.

Application: alternative stucco systems, suspected stucco failure, insurance claims, properties with impending warranty expirations, litigation support, and further due diligence for real estate transfers.

Some Quick Facts About Stucco

Conventional Stucco Systems – Stucco or ‘portland cement plaster’ has been traditionally installed as a 7/8” three-coat system consisting of a 3/8” scratch coat, a 3/8” brown coat, and a 1/8” finish coat. Most standards require that the scratch coat fully embeds a self-furring metal lath, which is applied over Grade D building paper or other approved weather-resistive barrier. When installed with adequate drainage and flashing details, a properly-installed three coat system will meet or exceed performance expectations.

Alternative Stucco System – Several alternative approaches have emerged in efforts to cut construction costs. Like traditional stucco, these systems are Portland cement-based but they may also contain various proprietary mixtures, polymers, and reinforcing fibers that allow for thinner layers and quicker installation. When an alternative system is used, documentation called an ‘Evaluation Report’ must be submitted by the contractor and approved by the local building authority for each construction project utilizing that particular system. An evaluation Report specifies installation procedures and physical characteristics of the stucco system as determined by its manufacturer. If your structure involves an alternative system, contact your municipal building inspector to review permit files and Evaluation Reports.

Is it a stucco problem? Increasing awareness of water-damaged stucco buildings has lead many to assume that stucco is an inferior cladding system, which is not the case. Damages within stucco and other cladding systems are often the result of other construction deficiencies such as window installation, window failure, grading, and flashing details. While an inferior stucco system can certainly exacerbate the problem, it is only one of several issues to consider when evaluating construction defects and water intrusion.


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