FAILURES
David H. Nicastro, PE, F.ASTM
After suffering property damage, the last thing a building owner wants is another failure of the same system. After determining the failure’s cause, an appropriate and durable remedy should be designed and implemented. First, an important choice has to be made regarding the breadth and depth of the remedy.
The following remedial options are commonly available for building envelope remedies, and presented in order of increasing cost, time, and disruption—but also in order of increasing likelihood of success, durability, and warranty coverage. With slight adjustments, similar remedial option levels are available for other systems, such as parking garage structural repairs.
Level 1: Isolated repairs
Repairing only the known distress locations is the lowest-cost, fastest, and targeted approach. It could be considered ‘maintenance’ instead of ‘remedy’ because the underlying problems causing distress are not addressed—they are assumed to be still operative at other locations, so more distress will inevitably develop elsewhere.
Example: replacing sealant only at failed joint locations, but not comprehensively replacing the rest of the sealant at the same time.
Level 2: Proactive repairs
Proactive repairs involve extrapolating from the distressed locations and implementing remedy at all similar details. It may involve more in-depth remedial measures, not just more locations.
Example: comprehensive wet-sealing (applying silicone sealant over window gaskets and metal frame joints and seams) while only certain windows leak.
Level 3: Comprehensive external remedy
In a comprehensive external remedy approach, failed materials are left in place, but rendered obsolete by installing new materials over the existing defective systems. This solves underlying problems while avoiding demolition cost and disruption.
Example: applying an elastomeric wall coating to stucco instead of removing it to address
a failed water-resistive barrier (WRB)—the solution for the failure in the photo.
Level 4: Replacement
The highest level of remedy, this involves total replacement of failed systems rather than fixing them. It may be considered ‘betterment’ or ‘economic waste’ if a lower remedy level could solve the functional problem. (One should discuss with an attorney if seeking to recover the high cost of a replacement solution from other parties.)
Example: re-skinning a building with new windows and cladding because of leaks.
All these options have merit in certain situations, but the distinctions are not always understood. If a consultant recommends a Level 1 or Level 4 remedy, an owner should consider obtaining a second opinion. The former is usually too little, and the latter is frequently too much—most failures need to be addressed by either a Level 2 or Level 3 remedy.
The opinions expressed in Failures are based on the author’s experiences and do not necessarily reflect those of The Construction Specifier or CSI.
David H. Nicastro, PE, F.ASTM, started the Failures column for The Construction Specifier in January 1994. He is the founder of Building Diagnostics Inc. and Engineering Diagnostics, specializing in the investigation of problems with existing buildings, designing remedies for those problems, and resolving disputes arising from them. Nicastro is a licensed professional engineer, and leads the research being performed at Building Diagnostics’ testing center, The Durability Lab, at the University of Texas at Austin. He can be reached by e-mail at dnicastro@buildingdx.com.
David, David, David…this perspective needs to be challenged and qualified. Your “Level 2 and 3” approaches should be combined and more aptly labeled as “band-aid” repairs because they often require long term increased maintenance to the owner that would ordinarily not be necessary had the conditions been correctly addressed. Treating the symptoms is never the same as curing the problem. Neither does anything to “solves underlying problems”. Neither are particularly ‘proactive’ or ‘comprehensive’ as they are labeled. Putting new good outer material over ‘failed materials …left in place’ does not solve the underlying condition, by definition. Topical sealants and elastomeric coatings are at best short term solutions that do not permanently address the failed condition.