With a damaged masonry façade, active leaks, and corroded steel lintels, this historic building required a complete retrofit and seismic upgrade before it could be occupied. Read on to find out how RDH stepped in and provided solutions to repair the enclosure and improve building performance, while honoring its historic character.
In 2009, the Oregon College of Oriental Medicine (OCOM) launched their plans to move into the historic building that was previously occupied by the Globe Hotel in Portland’s Chinatown district. The original building was constructed in 1911 and consisted of solid, unreinforced, brick masonry, and a heavy timber frame. Because the building remained unoccupied and unmaintained for a long period, the masonry façade was seriously deteriorated. The owners of the College knew that a complete retrofit and seismic upgrade would be necessary before the educational facility could be occupied.
RDH was retained to complete a condition assessment as well as to determine what repairs were required. Because of the age and delicate nature of the masonry façade, RDH had to carefully choose exploratory opening locations in order to confirm conditions of hidden components, materials within the assemblies, and window interfaces. Following the assessment, RDH uncovered numerous cracks in the exterior masonry assembly and around the window sills, damaged paint, and active leaks to the interior, consequently recommending that the deteriorated assemblies required immediate attention.
Of particular concern was the condition of the old steel lintels over the windows. The lintels consisted of two parallel steel channels spaced several inches apart to support the mass masonry wall above. Steel angles were connected to the bottom of the steel channels with rivets and these angles supported the outer wythe of brick masonry. The original construction lacked flashings at these lintels. Years of corrosion and rust flaking off the steel caused a build up of debris behind the brick. In addition, the expansive forces of the corrosion pushed up on the outer brick wythe. The combination of upward forces from the flaking steel angles and outward forces from continued accumulation of corroded steel on the back of the brick resulted in an unsafe outward bow in the brick. Left much longer, the brick could have failed suddenly, creating an impending life safety danger.
As part of the design team, RDH assisted in providing a solution that not only mitigated the ongoing corrosion, but also significantly improved the water penetration resistance and drainage characteristics of the masonry at the lintels. The cavity behind the brick veneer at the lintels was turned into a drained rainscreen cavity while the masonry above the lintel remained a mass wall assembly.
During the construction phase of the rehabilitation, RDH assisted with the design and review of window rough opening detailing to improve water penetration and airtightness around the windows. RDH also performed general building enclosure field review throughout the construction stage.
The OCOM was successfully retrofitted and the project was completed in 2012, achieving LEED Gold certification with a durable and safe outer rainscreen veneer that looked identical to the original brick head.