Old Republic

Title: Old Republic

Award Category: Exterior Wall

Project Address/Location

307 North Michigan Avenue

Chicago, IL 60601
United States

Submitted By: Matthew Novesky

Company Info

WJE

10 South LaSalle Street
Suite 2600
Chicago, IL 606003
United States

312.372.0555

[email protected]

Project Description and Background: Constructed in 1924, the Old Republic Building, located at 307 North Michigan Avenue in Chicago, Illinois, is a 24-story steel frame commercial building clad with terra cotta on the north, west, and south facades and face brick with terra cotta window lintels and sills on the east facade. Designated a Chicago Landmark in 2010, a three-year facade restoration project was completed in 2023. The building Architect (New World Design, Ltd.) retained WJE to perform a limited close-up assessment (via suspended scaffolding and industrial rope access) in 2016 to develop a scope of repair work along with unit costs for a masonry contractor (Central Building & Preservation, L.P. - Central) to provide initial pricing. The repairs were implemented using a Design-Build approach with WJE designating the locations and types of repairs once access to the building facades was provided by Central. Inspections and repair work was performed using mast-climbers on all facades except the east, where swingstages were used. Mast-climbers were well suited for this project because:  the main roof contains an operating rooftop restaurant and daily access was prohibited,  two facades are located on major public streets (Michigan Avenue and East Wacker Place), one facade on the property line with an adjacent plaza and staircase owned by others, and a lower level alley on the north facade,  mast-climbers provided a high-capacity working platform and an area for material staging and storage since space on the site was very limited.

Scope: As stated above, the entire restoration project was performed using a Design-Built method. Sequencing of repair work was performed as follows:  WJE performed an initial inspection at each drop to identify specific locations of work based on previously developed unit costs,  Central removed units to be replaced or salvaged, repaired, and reinstalled,  WJE reviewed existing as-built concealed conditions and modified scope of repair work and repairs as necessary to address the actual conditions,  Central cleaned and prepared areas for installation of terra cotta and other repairs,  WJE reviewed preparation work and performed periodic inspections as Central implemented repairs,  WJE performed a punchlist and final inspection drops to verify repair work had been completed in general accordance with the intent of the contract documents. Scope of repair work included, but not limited to:  100 percent reconstruction of the terra cotta cornice (except at the northwest corner which was previously rebuilt by others),  100 percent reconstruction of the 21st floor terra cotta water table,  reconstruction of several terra cotta clad two-story columns between the 21st and 23rd floor levels,  100 percent replacement of previously installed limestone replacement units with new terra cotta units,  100 percent reconstruction of all building corners (between the 5th and 21st floors),  Replace cracked, delaminated, and previously spalled terra cotta units throughout the facades,  Facade stress relief repair,  Face brick replacement and shelf angle repairs.  Cleaning and recoating of original steel windows with isolated steel frame repairs  Replacement of 2nd floor windows with new steel framed window to match existing historical profiles and site lines.

Solution: Traditionally, for a building envelope repair project, inspections are performed by an Architectural/Engineering (A/E) firm to develop a defined scope of repair work that includes reviewing inspection openings to document existing as-built conditions. With the Design-Build facade restoration methodology, drawings are prepared more to show general scope and the conceptual repairs. Building elevations and plans showing the location of repairs are supplemented with schematic detail sheets to convey the general repair concepts, with the understanding that many of the concealed conditions will not be understood until the project work actually begins. Once the contractor has accessed the building, locations and types of repairs are identified by the A/E and implemented by the contractor. While a general overall repair plan is in place before the work begins, actual repair work is defined and implemented in the field. Developing repairs based on actual conditions allowed for a collaboration between WJE and Central in selecting available materials and anchorage detailing that Central could readily install. Being a historically designated building, terra cotta replacement units were obtained to replace previously installed non-historic and existing distressed terra cotta units to restore the original historic facade. Due to fabrication and lead times, acquiring new terra cotta replacement units required early decision to be made between the building Architect, WJE, and Central. Salvaging and relocating the location of existing salvageable units was also utilized to allow for construction at areas that were to be completely rebuilt to proceed until new units arrived.

Value: Coordination and corporation between the building Architect, WJE, and Central was essential for the success of this project. The Design-Build process reduced both the project cost and timeframe by allowing Central to mobilize for construction earlier than a traditional inspection, development of repair documents, bidding, and construction process would allow. Repair details were developed as the project evolved and decisions were often made in the field to allow the construction to proceed without delays. Existing materials, such as ferrous metal steel framing and facade support members, were evaluated in the field once they were exposed. Since the existing steel members were typically found to be in serviceable condition, cleaning and recoating of existing steel members was performed, along with minimal in-kind replacement of individual members with significant loss of section. This also helped to reduce the project cost and compress the construction schedule.

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