Track 4: This New World: Preservation technology and emerging issues within our historic buildings and built landscapes
High-Resolution Photography Condition Survey of the U.S. Custom House Dome, Philadelphia PA
Monday, September 24
10:30 AM - 12:00 PM
The U.S. General Services Administration’s (GSA) Mid-Atlantic Region completed a high-resolution photography condition survey of the ornate rotunda dome at the U.S. Custom House in Philadelphia, PA. Opened in 1934, the U.S. Custom House is a 17-story Art Deco landmark in Philadelphia’s Old City neighborhood.
The dome is the centerpiece of the building’s highly decorative interior. Rising 50 feet above the first floor, with a diameter of 37 feet, the dome is constructed of coffered plaster with rows of gold painted plaster shells, which decrease in size from the frieze to the cast aluminum oculus ring at the top of the dome. Punctuating the intersection points of the coffers are smaller pink and silver plaster ornaments depicting various marine life. A pale blue cupola provides a soft glow above the oculus ring.
Because of the size of the dome, the extraordinary detail, and the inadequate lighting, it was difficult to determine the condition of the dome. The dome was last inspected as part of a repair and painting project in 1993. The estimated cost to scaffold the dome to do a condition assessment was $150,000+. GSA pursued PhotoSurveytm and PhotoDrawingtm services offered by Manassas Consulting LLC of Pittsburgh, PA.
The dome was divided into eight segments with each segment thoroughly photographed. The photographs were reviewed on site to look for condition issues, such as flaking paint or plaster cracks. These issues were then photographed with a longer lens for a higher resolution image of the problem area. The survey photographs were stitched together to form a seamless whole, providing one large image of each segment of the dome. The segment images were loaded onto a project website that included annotation tools, allowing users to review the images and annotate problem areas. Detailed images of condition issues were linked to the overall images. Once the images were completely reviewed and problem areas noted, the images were converted into line drawings that preserved the surface texture. These drawings represent a bid package that can be issued to contractors to bid on the noted repairs. The project website can also be made available to bidders, reducing the unknowns during the bidding process and hopefully resulting in better pricing with less change orders after award.
The end results of the survey provided good news. The dome is dusty but in good condition, with minor condition issues, such as peeling and flaking paint, and some small nail holes noted. The PhotoSurveytm and PhotoDrawingtm products cost $11,000 and provided GSA with a wealth of knowledge about the condition of the dome, insight into the way the dome was constructed, and a valuable detailed record of the decorative elements in the dome for disaster resilience.
- Understand the use of high resolution photogrammetry to provide disaster resilience
- Understand the creation and use of blueprints with surface texture for work scope definition
- Understand the use of photogrammetry to define the general work scope
- Understand the cost benefits of high resolution inspection to reduce field mobilization cost