Historic Facade Preservation Survey

The Challenge

A historic preservation group in Pasadena needed detailed documentation of four terra cotta and brick facades on a 1920s-era commercial building before a seismic retrofit project. The facades featured ornamental cornices, arched windows, and decorative medallions that needed to be preserved or replicated if damaged during construction. Traditional measurement methods could not capture the complex ornamental geometry accurately.

Our Approach

We combined terrestrial LiDAR scanning with drone-mounted photogrammetry to capture all four facades from ground level to parapet. The terrestrial scans provided millimeter-accurate geometry of the ornamental details, while the drone captured the upper levels and roofline that were inaccessible from the ground. The data was processed into detailed facade elevation drawings with dimensions, an orthorectified photo mosaic for condition documentation, and 3D models of the ornamental elements that could be used for replication if needed.

Results

• All 4 facades documented in 3 days including drone flights
• Ornamental details captured at sub-millimeter accuracy for replication
• Preservation board approved seismic retrofit plans based on our documentation
• Contractor used facade elevations to plan scaffold placement — saved 2 days of setup
• 3D ornamental models used to fabricate 6 replacement medallions that matched originals exactly