Deborah Slaton, David S. Patterson, AIA, and Jeffrey N. Sutterlin, PE
Even within buildings experiencing recurring moisture-related issues, visible surfaces of interior finishes do not always provide an accurate indication of the underlying conditions within the exterior wall assembly. While non-destructive and minimally invasive investigation methods can determine the presence of elevated moisture levels within wall assemblies, inspection openings to expose underlying conditions provide the most comprehensive assessment tool to identify the extent and source(s) of water damage.
Initial openings may be relatively small due to project limitations or as an initial step to understanding the condition of the interstitial wall assembly. However, the openings may need to significantly increase in size depending on preliminary findings.
When performing inspection openings in areas suspected of moisture-related issues, the potential for organic growth within the wall assembly should be considered before creating an interior opening in the exterior wall. A qualified professional such as a certified industrial hygienist (CIH) should be consulted to develop containment protocols and a performance work plan prior to performing openings that could, absent proper procedures, potentially result in contamination of interior spaces.
Although there are currently no national standards regarding mold assessment and remediation, an oft-referenced guideline that provides approaches for addressing suspect organic growth within commercial, school, and residential buildings is the New York City Department of Health and Mental Hygiene’s 2008 Guidelines on Assessment and Remediation of Fungi in Indoor Environments.
One recent example illustrating the value of larger inspection openings involved a healthcare facility initially thought to experience chronic condensation issues resulting from elevated interior humidity levels and thermal bridging at windows. Further studies revealed water penetration into the interstitial wall cavity was also occurring at windows due to systemic integration deficiencies within the window assembly, and between the windows and the adjacent exterior wall. As the building’s interior finish consisted of ceramic tile adhered to gypsum sheathing, there was little to no visible evidence on the exposed wall surface of damage within the wall cavity.
Following installation of proper containment protocols developed by a CIH, the underlying wall conditions were exposed to determine if water-related damage existed within the interstitial wall construction, and, if so, to what extent. After initial small openings were examined, removal of interior finishes at larger openings revealed extensive damage to the wood framing and wall sheathing of this seven-year-old structure—damage that required replacement of exterior cladding and sheathing, framing members, and interior finishes.
In this example, creating inspection openings of sufficient size provided the opportunity to identify the extent of damage within the wall cavity so appropriate repairs (which required nearly complete demolition and rebuilding of the exterior wall), could be developed and coordinated with the facility.
Deborah Slaton is an architectural conservator and principal with Wiss, Janney, Elstner Associates (WJE) in Northbrook, Illinois, specializing in historic preservation and materials conservation. She can be reached at email@example.com.
David S. Patterson, AIA, is an architect and senior principal with the Princeton, New Jersey, office of WJE, specializing in investigation and repair of the building envelope. He can be e-mailed at firstname.lastname@example.org.
Jeffrey N. Sutterlin is an architectural engineer and senior associate with WJE’s Princeton office, specializing in building envelope investigation and repair. He can be reached at email@example.com.