In a recent consultant's corner, Structural Engineer and Senior Consultant at Raths, Raths & Johnson Standards Robert J. Kudder discusses how testing and proven industry guidelines are key to performance.
A unique seven-story building in the Midwest exhibited leakage problems resulting in interior finish damage and mold problems. The leakage problem, evaluated following the protocol of ASTM E2128,1 identified two major water entry paths. The first and most severe was leaking windows, particularly around packaged through-wall air conditioner (PTAC) units as well as at frame joints and glazing gaskets.
Two before-and-after investigative ASTM C16012 tests were conducted. Although there are no industry standards for permeability rates, measured rates are judged to be reasonable for masonry assuming that there was a functional drainage cavity and flashing. Unfortunately for this building, water which penetrated the wall could not be handled by a deficient flashing system. Unsatisfactory initial installation of windows and masonry meant both had to be corrected to prevent further infiltration and damage.
With leakage problems being at the top of many building concerns, Kudder discusses methods of correction, obstacles to flashing repair, repointing as alternative means of repair and expected practices and lessons learned.