Chattanooga City Hall Annex Renovation: Modernizing an Occupied Municipal Building
Location: Chattanooga, Tennessee
Industry: Commercial & Corporate Facilities
Service: Occupied Space & Facility Renovation
The Situation
The City of Chattanooga needed to modernize the third and fourth floors of its City Hall Annex without closing the occupied municipal building. The renovation involved offices, conference rooms, elevator lobbies, restrooms, and support spaces, as well as major improvements to the windows, building envelope, plumbing, HVAC, electrical, and life-safety systems.
This was more than a finish renovation. JBrennon had to integrate new construction into an aging building with inconsistent dimensions, concealed deterioration, and undocumented system routing—all while City operations continued around the work.
The Challenge
Once demolition began, existing conditions varied significantly from what could be seen or documented before construction. Hazardous materials were discovered in flooring and ceiling assemblies, requiring coordinated abatement and resequencing of the work.
The building itself was not consistently level, plumb, or square. Walls, slabs, and window openings varied in dimension, which meant new assemblies could not simply be fabricated and installed from standard measurements.
Removing the existing windows exposed deteriorated substrates, incomplete flashing, unprotected steel lintels, and masonry conditions requiring repair. Water had also entered through failed parapet and exterior-envelope conditions, affecting masonry, structural interfaces, and interior finishes below the roofline.
Inside the building, existing domestic water, sanitary, HVAC, electrical, fire-alarm, and sprinkler systems did not consistently follow the documented routes. New piping, ductwork, wiring, ceilings, and architectural finishes had to be coordinated within the same constrained spaces.
How We Worked
JBrennon divided the renovation into manageable work areas, maintained separation from occupied portions of the building, and continued work in unaffected spaces while hazardous-material abatement and clearance activities were completed.
Field dimensions were taken from the actual structure rather than relying solely on the original drawings. JBrennon provided the architect with field information, constructability assistance, and recommended solutions for new window blocking, casing, trim, flashing transitions, and adjacent finishes. This allowed the final details to respond to the building that was uncovered—not the building everyone expected to find.
Architectural, envelope, structural, plumbing, mechanical, electrical, and fire-protection work was coordinated as one integrated renovation. When rerouted systems affected walls, ceilings, floors, or finished surfaces, JBrennon managed the associated cutting, reinforcement, patching, trim, and finish restoration needed to deliver a complete result.
What We Upgraded and Installed
The completed City Hall Annex renovation included substantial improvements throughout the third and fourth floors.
Interior spaces and finishes
Renovated offices, conference rooms, elevator lobbies, restrooms, and support spaces.
Completed interior demolition and reconstruction required for the new layouts.
Installed new ceiling systems following hazardous-material abatement.
Installed and replaced doors, frames, architectural trim, corner guards, restroom accessories, and specialty finishes.
Repaired and refinished walls, ceilings, floors, and other surfaces affected by demolition and system rerouting.
Adapted new finishes and architectural components to uneven floors, irregular walls, and nonuniform existing dimensions.
Windows and exterior-envelope improvements
Replaced existing window assemblies.
Installed new field-coordinated window blocking, casing, trim, and transitions.
Installed exterior-rated substrates at deteriorated window openings.
Protected and waterproofed exposed structural steel and lintels.
Restored window headers, lintels, and surrounding masonry interfaces.
Installed new flashing and sealing systems to manage water at window openings.
Coordinated storefront glazing, trim-out, and finish restoration.
Matched new exterior and interior finishes to the existing architectural character.
Parapet and masonry repairs
Removed deteriorated materials at affected parapet and exterior-envelope areas.
Installed new flashing and waterproofing components.
Repaired and treated exposed masonry.
Sealed deficient mortar joints and exterior transitions.
Corrected water-entry conditions contributing to interior finish damage.
Restored surfaces affected by long-term moisture infiltration and structural movement.
Restroom and plumbing upgrades
Installed new restroom fixtures and accessories.
Rerouted domestic water piping through the existing building.
Rerouted sanitary piping between floors to serve the renovated layouts.
Coordinated plumbing routes with structural, ceiling, HVAC, and electrical constraints.
Completed the wall and slab modifications, reinforcement, patching, and refinishing required for the new plumbing installations.
Mechanical and ventilation improvements
Modified restroom exhaust systems.
Rerouted HVAC ductwork around existing structural and electrical conditions.
Modified rooftop and floor-level mechanical connections.
Coordinated ductwork and equipment connections with the new ceilings and room layouts.
Restored architectural finishes disturbed by mechanical-system revisions.
Electrical upgrades
Reconfigured and refed electrical circuits serving the renovated spaces.
Relocated receptacles and outlets to support the new office, conference-room, restroom, and technology layouts.
Modified lighting systems and associated controls.
Coordinated electrical pathways with new ceilings, piping, ductwork, walls, and architectural finishes.
Integrated new electrical devices with the building’s existing infrastructure.
Fire-protection and life-safety corrections
Coordinated sprinkler modifications with the renovated floor plans and ceiling systems.
Integrated fire-alarm devices with the new layouts.
Completed emergency-system modifications required by the renovated spaces.
Corrected legacy conditions discovered during construction so affected systems could meet current code requirements.
The Outcome
The City of Chattanooga received modernized, occupancy-ready third- and fourth-floor spaces supported by renewed architectural finishes, reconstructed window openings, repaired masonry and parapets, and upgraded building systems.
The completed project addressed more than the visible renovation. JBrennon corrected water-entry conditions, protected previously exposed structural components, created workable routes for plumbing and mechanical systems, modernized electrical and life-safety infrastructure, and fitted new construction to a building with highly irregular existing conditions.
Throughout this work, the City Hall Annex remained occupied and operational. The result is a safer, more functional, code-compliant, and maintainable municipal facility—delivered as a complete renovation rather than a collection of disconnected repairs.