50 & 70 BAIF BOULEVARD
BUILDING ENVELOPE ASSESSMENT & REMEDIATION
OVERVIEW
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FORSMITH Building Science Consultants (FORSMITH) was retained to conduct an assessment of two high-rise residential condominium buildings located at 50 and 70 Baif Boulevard, Richmond Hill. As part of the assessment, a visual review of the building envelope of each building was completed. Façade elements included brick masonry veneer, structural shelf angles, punched windows, aluminum framed window wall assemblies with fixed and operable insulated glazing units (IGU’s), roof parapets, exterior sealants, mechanical penetrations, conventionally reinforced concrete balcony slabs, precast concrete balustrades, and the various transitions between these building components. FORSMITH utilized cameras and drones (UAV) to review components on upper floor levels where physical access was a challenge. Test openings into the existing brick masonry veneer were completed in several strategic areas where shelf angle deterioration was observed, in order to closely review the issues while also verifying the as-built details. Given the age of the buildings (constructed in the 1970’s), the overall purpose of the assessment was to determine the condition of each major component noted above, some of which were near the end of their service life, and to establish a remedial plan for the foreseeable future, where repairs could be planned and divided into manageable capital expenditures over a number of years. The ultimate intent was to do this in a manner that was not only practical, but also aligned with the corporation’s reserve fund. As a result, each building component was categorized with high, medium and low priority level in terms of the remedial action required to address the ongoing deterioration.
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PROBLEM
The most critical and commonly observed form of deterioration was related to the steel shelf angles, which are intended to structurally support the brick veneer wall at each floor level of each building. Numerous locations with evident deterioration in the form of rust staining along the shelf angles were identified. The masonry test openings further supported the visual review, as they revealed significant corrosion and section loss. Section loss, which is the reduced thickness of the steel angle, presents a structural concern. Corrosion is typically indicative of deterioration to the steel shelf angles as a result of moisture ingress in the wall assembly. A lack of adequate protection (ie. flashings and a weather-resistive barrier) of the angles and inadequate drainage provisions were concluded to be the major contributors to the deterioration. Another frequent finding during our visual assessment of the building envelope was the localized deterioration of the brick veneer itself. The majority of notable deterioration was in the form of spalling brick, cracking mortar, mortar washout and efflorescence. All this evidence pointed to excessive moisture in the wall assembly due to weather exposure and poor building envelope detailing (eg. drainage, flashings, etc.). Following the assessment, FORSMITH was tasked with preparing specifications and repair details to immediately address a vertical drop at 50 Baif Blvd where shelf angle deterioration was significant enough to warrant full removal and replacement. In addition to the structural issue, there was one (1) unit on this drop that had experienced active leaks to the interior for several years. Despite numerous repair attempts to address the water infiltration, the leaks persisted until FORSMITH took on the challenge to once and for all resolve them.
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CHALLENGE
One the challenges during the assessment portion of this project was access to each major component in the building envelope, to be able to review its condition. That is why FORSMITH employed numerous methods and technologies to do so, including the use of cameras, drones, suspended stages, boom lifts, masonry test openings and the interior review of a sample of units. Moreover, gaining access to relevant building information was challenging as well as recordkeeping of existing plans and previous repair projects was limited, due to the construction of the buildings in the 1970’s. Where able to, FORSMITH reviewed existing architectural, structural and mechanical drawings and verified them against the visual review and the as-built conditions identified during the exploratory openings. On the other hand, the major challenge during the shelf angle remediation project was determining the source(s) and pathway(s) of the existing leaks, and the appropriate repair detail(s) to address the underlying issues. Ultimately, an iterative process of investigative water testing and subsequent building envelope repairs was required to resolve the leaks. This was efficiently completed by FORSMITH with close cooperation and coordination with the restoration contractor.
SOLUTION
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Our recommendations for repair focused on the most critical areas exhibiting significant deterioration, in an effort to address these issues in the short term in order to mitigate further deterioration and prolong the overall service life of the structure. In turn, an estimated construction budget was presented to the owner based on historical data for the cost of similar work, adjusted for factors such as inflation, location, risk, size, time, quality, etc. Once retained, FORSMITH prepared a parking garage remediation design package including detailed specifications and drawings. By way of a competitive bidding process (ie. via tender), a general contractor was retained to complete the specified repairs. FORSMITH in turn applied for a building permit and provided engineering services including periodic technical field reviews, contract administration and project management during the entirety of the project duration. Working alongside the general contractor, FORSMITH was able to deliver the project on budget and on schedule, to the satisfaction of the client.
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