![]() ![]() Windows were tested under ASTM E-1105 under differential pressure and the exterior stucco façade was tested with a spray rack with no differential pressure however, we did not observe any liquid water penetrating the interiors of these units. Most of the damage was on the backside of the exterior wood sheathing as seen below.ĪBBAE staff spent 2 days performing extensive water testing and invasive forensic testing of the windows and wall assemblies. We removed of the interior gypsum board and observed severe damage inside the wall cavities. Based on our visual observations, we identified several potential sources of wall and window leaks and proceeded to perform water testing to identify the source of the leaks. We opened up gypsum board in the various units available to us and observed severe damage to the exterior oriented strand board (OSB) sheathing. Once we noticed how extensive the damage visible damage was, we extended our investigation. The contractor who did the original repairs suspected that the gutter penetrations were causing the water intrusion. ![]() Next we investigated the corner areas of the units. We began by investigating around the windows (as is our standard protocol). Our staff documented high moisture readings (96% RH and 73-degree temperature) in this unit even though it had been vacant for several years. Out of the eight units that we were given access to, we observed damage in one unit in Building 1500, at a wall that matches the same elevation at the Northwest corner as the previously repaired unit stack in Building 1400. We were not given access to the original stack of units that had the previously repaired damage. All the units selected for visual inspection were vacant units. In the second go-around, the client and contractor hired us to perform an investigation to understand the factors that were not understood at the time.Īs part of our initial study, we were given access to eight apartment units and we performed visual inspections of the interiors. Approximately one year before our investigation, the same stack of units that were originally remediated failed, repeating the development of mold and biological growth on the inside face of the exterior walls. The interior and exterior were fully remediated prior to ABBAE’s involvement so the original evidence was lost. Management believed there was a deficiency with the cement plaster so they hired a contractor to replace all the plaster assembly in a three-story high unit stack of the façade. Water damage and biological growth were reportedly uniform in nature and varied between heavy damage on the 1st floor and less damage on the 3rd floor. There were reports of mold and moisture damage on the interior walls of one stack of three units. The wall assembly consists of wood sheathing over wood framing, two layers of 60-minute weather resistive barrier, and a three-coat stucco system. The five-building, three-story apartment complex was built 2011. (ABBAE) was retained to investigate reported leaks and water intrusion at a 186-unit apartment complex in San Ramon, CA. The nature of these moisture intrusion failures includes construction defects and changes the industry has made for energy efficiency including air barriers and vapor retarders. This paper will also provide an analysis of code requirements for ventilation and actual system performance. The discussion will include mechanical ventilation involved in condensation control, including make-up air and exhaust This allows us to understand how buildings behave in real time versus design parameters. This paper will include forensic studies of moisture movement and condensation control where data loggers were used to measure moisture movement alongside WUFI analysis of actual assemblies in occupied buildings. Condensation and moisture diffusion damage can occur with or without designed air barriers and it is important to understand the role ventilation plays in the design. Understanding and predicting moisture movement within and through exterior wall systems is one of the most important factors effecting envelope performance today. We utilized WUFI model studies as well as actual data logger information. We discuss lessons learned from investigation and analysis of projects in California, where This paper will focus on the increasing number of interior wall assemblies that are experiencingĮxcessive moisture damage due to combination of moisture diffusion and condensation. Go hand in hand with exterior enclosure, air barriers and mechanical ventilation. Humidity and condensation control in buildings Due to energy code changes, better enforcement, and as a matter of good practice, we are making buildings more and more air tight. ![]()
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