Project Details
Historic Atlanta Federal Building Posed Architectural, Structural, and Blast Protection Challenges
This historic window replication project involved replacing 328 original wood double-hung windows with fixed aluminum replication windows manufactured by Wino Window Company, St. Louis.
Built in 1920, The Tuttle Annex is a five-story timber frame building with red triple-brick walls. The exterior of this historic building was intended to be a model of successful preservation and rehabilitation.
Problems, Issues, Obstacles
Meeting modern thermal performance, GSA blast mitigation and local historical requirements posed a unique design and fabrication challenge. The new fixed heavy commercial windows had to closely emulate the sightlines, meeting rail, muntin, and sloped putty aesthetics of the original wood double hung windows.
The original 4-inch-wide vertical wood mullion had to be painstakingly replicated in three dimensions to meet Atlanta historical building requirements. At the same time, the new window mullion would substitute wood with a custom extruded tubular aluminum profile which caps a special insulating system inside.
Finally, all new windows had to be securely anchored to the existing walls, including some requiring fiberglass epoxy anchor fortification to handle the heavier load.
The Solution
The windows to be replaced were, for the most part, on three sides of the building. One building section was made of concrete with veneer perimeter of terra cotta clay tile block. The general contractor, BECK Group, Atlanta, added a steel grid, connected from slab to slab, to anchor these windows. Two other sections are of timber-frame construction with triple-brick perimeter wall. There, the windows were anchored into the brick with a Fiber Reinforced Polymer (FRP) wrap on the inside - using resin and the fiberglass matt fabric to strengthen the joints.
There was a steel angle attached to the existing masonry in three-fourths of the building. Wino provided custom versions of its 1450 series windows, with the typical window size: 3’ 7” × 8’ 3”
The bulk of the job consisted of twin openings for the Fairlie Street side of the building. All replacement windows are fixed and made to simulate the original wood double hungs, including brick mold and sightlines.
At what was the meeting rail of the original double hungs, an aluminum extrusion was added with a Novard adhesive to simulate the rail and provide horizontal reinforcement.
Exterior applied muntins simulated the original windows’ true divided lites. And a custom 4-inch-wide vertical mullion separated the twins.
The three-dimensional vertical mullion cover that Winco developed especially forth is project provided historical design authenticity as well as improved thermal and blast resistance characteristics.
Click the link below to learn more about The Tuttle Annex project!
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