The Best Way to Stop a Leak? Prevent It.

Nov. 1, 2008

Managing water infiltration in façades calls for early intervention and appropriate repairs

Even the most durable of building materials, from brick and stone to concrete and steel, eventually succumbs to the forces of time and the elements. If deterioration is inevitable, are leaks, too? Not necessarily. While even the most diligently maintained structure will show signs of moisture intrusion from time to time, pervasive damage from leaks is avoidable. The solution? Routine, thorough evaluation of façade conditions, coupled with prompt repair measures that address the source of the problem.

To avoid "band-aid" repairs that, at best, will need to be repeated or, at worst, will exacerbate the problem, an investigation into the cause of the leak should be conducted. Placing sealant in cracked brick won't stop moisture infiltration if the source of the leak is deteriorated mortar joints.

Check for crumbling or open joints on masonry façades, as well as for signs of moisture entry, such as stains/efflorescence, cracks, and spalls. On concrete, look for cracked panels or slabs, spalls, and stains. Cracked or debonded sealant is a common source of moisture entry on concrete or stone exteriors. Glass curtainwall can exhibit rusted or bent mullions, as well as the same types of glazing failures found in standard punch opening windows, including loose or cracked gaskets and seals, and fogged or etched glazing. At windows and doors, hardware and operable mechanism failures can also be trouble spots.

If the underlying problem remains elusive, an architect or engineer might need to employ test probes, pressure differential testing, laboratory analysis, or other investigative measures to accurately pinpoint the source of a leak.

Identifying signs of water intrusion and determining the leak's probable cause are the most challenging parts of the remediation process, not only because the survey involves some detective work, but also because investigations can reveal unforeseen problems that change the scope of anticipated repairs.

Sealant application is often the first impulse in leak control, but it can lead to problems if done inappropriately. Although properly designed and maintained sealant joints are critical to keeping many buildings watertight, misused sealant can block water egress points, causing masonry failures and more leaks.

Aesthetics, durability, and cost effectiveness are generally the main criteria in selecting a repair option, although occupancy demands, scheduling, logistics, and other concerns may play a role in determining the most appropriate repair strategy for a given situation. In general, opting for quality materials and skilled installation, with detailed documents, specifications, and project oversight, repays initial expense with longevity.

To catch leaks early, and to stop new leaks from developing, establish a regular façade-maintenance program. Collect observations of existing conditions in a written report, and then use this information to prioritize maintenance items, such as repointing mortar joints, replacing aging sealant, or repairing broken window hardware. Addressing potential sites of water entry saves the time and expense of chasing down the source of a serious leak later.

Arthur L. Sanders is senior vice president at Hoffmann Architects Inc. and director of the firm's Connecticut office. Hoffmann Architects also has offices in New York City and Washington, D.C.

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