Foundation Wall Waterproofing Repair Strategies for Existing Buildings: The Long-Term View
Approximately half of all of today’s commercial and institutional buildings were built before 1980¹. Many of these buildings were conceived and designed for generations of use, but have outlasted, or will soon outlast, the functionality of their below-grade waterproofing systems. In the authors’ experience, competent below-grade waterproofing systems generally have a service life of 40 to 50 years before remediation may be required. Deteriorating or failed below-grade waterproofing systems will begin to allow leakage into below-grade foundation walls and adjacent interior spaces damaging interior finishes, disrupting building operations and causing deterioration of structural components. Where below-grade building spaces consist of unfinished areas, such as parking decks or mechanical spaces, some leakage may be tolerable, but buildings with finished below-grade spaces require remedial waterproofing repairs to address leakage. In other cases, owners are purchasing buildings with the desire to repurpose previously unoccupied below-grade spaces, and remediating water infiltration through below-grade foundation walls to address leakage or to meet the changing performance demands presents significant technical and logistical challenges. This article discusses remedial waterproofing strategies for foundation walls.