Graham-Terry Apartments rehabilitation

Title: Graham-Terry Apartments rehabilitation

Award Category: Exterior Wall

Project Address/Location

2014-2020 Terry Avenue

Seattle, Washington 98121
United States

Submitted By: David Rash

Company Info

Morrison Hershfield Corporation

600 Stewart Avenue, Suite 200

Seattle, Washington 98101
United States

(206) 268-7378

[email protected]

Project Description and Background: The Terry-Graham Apartments is an affordable housing project that includes an historic apartment building, the Graham Apartments built in 1907, with an adjacent newer apartment building, the Terry Apartments completed in 1992, that are operated as one facility. The Terry Apartments feature wood frame construction with exterior cladding utilizing stucco and tile. The building developed significant exterior wall cladding issues shortly after its completion. In 2000-2001, the stucco cladding on the west elevations of the east and west wings of the Terry Apartments based upon rehabilitation drawings prepared by Exterior Research & Design/Trinity Engineering. In 2006, Wiss, Janney, Elstner Associates performed a general building enclosure assessment, which identified some minor issues associated with the low-slope roofing membrane and more serious issues with some of the exterior wall cladding, which resulted in the seventh story of the east elevation of the east wing being overclad with sheet-metal siding in 2009. In 2010, the Seattle office of Morrison Hershfield (MH) performed a preliminary building enclosure assessment, which identified some minor maintenance issues to be addressed, as well as possible areas of concern that the property owner should monitor in regards to the stucco wall cladding. In 2017, MH was requested to assist in identifying a water leak in the east elevation of the east wing as well as to perform a more comprehensive assessment of the exterior wall conditions in 2018. The impetus for the exterior wall assessment was driven in part by Bellwether Housing, the property owner, to assist in deciding whether to retain the property or sell it.

Scope: MH initially performed a limited leak investigation that included interior exploratory openings at the exterior wall of the east elevation of the east wing of the Terry Apartments building, which suggested that sealant failures and fasteners backing out with the 2009 sheet metal overcladding was the likely cause for the water intrusion issue and recommended a more extensive assessment of the wall. The subsequent wall assessment in 2018 included ten exterior exploratory openings which indicated that the stucco cladding was continuing to perform poorly with one exploratory opening revealing minor deterioration of the exterior wall sheathing and wood framing. At this time, recladding the building was recommended in the immediate future. Due to the increasing value of the land on which the building is located, the possibility of selling the property and replacing the existing residential units elsewhere had become a consideration. To obtain a better indication as to how generalized the findings from the 2018 east elevation wall assessment might be for the entire building, MH performed infrared thermographic surveys of the exterior walls which found some limited thermal anomalies, but basically reinforced the recommendation from the exterior wall assessment that the building be reclad in the immediate future to prevent extensive deterioration from developing. Bellwether Housing chose to retain ownership of the property and to undertake a major rehabilitation the building. Rehabilitation work at the adjacent Graham Apartments was limited to window replacement and interior upgrades.

Solution: After the decision was made to retain ownership of the Terry-Graham Apartment complex, Bellwether Housing assembled their project team. ARC Architects of Seattle was selected as the design professional of record, with Emily Wheeler as the principal architect for the firm. Rafn Construction of Bellevue was selected as general contractor with Patrick Quinn as the project superintendent. Morrison Hershfield was selected as the building enclosure consultant to ARC Architects, with Ken Chin as technical architect and David Rash as project manager. Early on, the project team agreed that the existing stucco and tile cladding would be replaced with fiber-cement siding installed over preservative-treated plywood furring strips to create a rainscreen assembly. The existing vinyl windows were sufficiently near the end of their service life that full replacement of the windows was included in the rehabilitation scope. Although not directly related to the exterior rehabilitation, functional upgrades to the interiors of the residential units were also included in the project scope. Roof replacement was not part of the original project scope although there were some concerns as to how to detail the interface between the existing metal roofs and the replacement cladding. While design was under way, a site walk with ARC Architects, Rafn Construction and Morrison Hershfield was performed during which it was discovered that several metal roofing panels had become displaced, bringing into question the utility of retaining the existing metal roofs unless a full assessment of their installation was made. Ultimately Bellwether Housing decided to include replacement of the metal roof areas as part of the project scope, which helped to simplify the issue of the metal roofs’ interface with the rain-screen cladding. In order to assure a clear understanding of how the new cladding should be installed and the new windows should interface with the cladding, mock-ups were performed for both the cladding installation and the window installation.

Value: The building enclosure consulting firm brought value to the project by bringing a wide range of testing expertise, a broad knowledge of design and construction, and a collaborative approach to problem solving. The infrared (IR) thermographic survey of the exterior walls was an atypical use of this testing method by Morrison Hershfield. Although there was no follow-up exploratory openings to confirm what the thermal anomalies represented, the infrared images combined with the recent wall assessment with exploratory openings were sufficient to give Bellwether Housing confidence that the extent of deteriorated structural framing and sheathing would be manageable. Indeed, the amount of deteriorated framing and sheathing encountered during construction was less than 2% of a $4-million-plus construction budget. When Rafn Construction raised concerns about the inclusion of sealant behind the installation fins of the new vinyl windows as their experience was that the sealant was invariably tracked into the interior spaces during rehabilitation projects, resulting in extra cleaning costs. Morrison Hershfield did not want to introduce an area of vapor impermeance as part of the cost for maintaining the air seal at the window openings, which a typical self-adhesive membrane would entail. Collaboratively, the project team agreed on the use of field-cut strips of VaproShield WrapShield SA installed over the installation fins to achieve the air while also maintaining the preferred vapor permeance. Bellwether Housing was pleased in having a project that did not require the displacement of any of their residents, while extending the life expectancy of one of their properties. In this regard, performing IR thermographic surveys of the exterior walls was a critical aspect of the project, as it is Morrison Hershfield’s understanding that had the IR surveys shown extensive thermal anomalies, indicative of widespread structural deterioration, the building would have been sold, resulting in a loss of the 107 residential units in the Terry Apartments, and possibly the 15 units in the adjacent Graham Apartments, at least temporarily. The importance of maintaining affordable housing with this project was illustrated when they included a video of one of Graham-Terry’s residents, “Mr. Captain Larry,” who was recently honored by the Seattle Mariners for his volunteer work, which can be seen in a recent youtube video.

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