AOC Pushes to Repair, Restore Capitol Dome

JMT Makes It Big In Mid-Atlantic Market — Damaged ornamental elements and other components from the U.S. Capitol dome are sent to a foundry in Utah operated by Historical Arts and Casting and molds are created from existing pieces and fragments. Replacement components are then cast from those molds. In some cases, one mold can be used to create multiple replacement pieces. In other cases, unique molds need to be used for pieces that have to fit perfectly into existing spaces.

Photo courtesy of Architect of the Capitol

Restore and Replace

While AOC intends to preserve as much of the existing dome as possible, hundreds of new ornamental pieces will need to be cast to replace those that are beyond repair. Crews are carefully removing and cataloging damaged pieces before shipping them to specialty contractor Historical Arts and Casting's Utah foundry. In some cases, a single mold is cast for identically designed pieces, such as the multiple 80-lb ornamental acorns that are attached to the outside of the dome. In other cases, each piece needs its own mold to ensure it will fit properly when installed. Crews found significant damage to the boilerplate balustrade, with up to 3 in. of corroded material found in some spots. All of the 288 balusters will be removed and many will be recast with unique molds.

Throughout the process, significant paint abatement is also required. An estimated 1,215 gallons of paint will be used to repaint the dome.

As the exterior work pushes toward completion later this year, work will ramp up on interior restoration of the rotunda. Crews have already installed a white catenary system in the shape of a doughnut, which protects the public spaces below while allowing the "Apotheosis" painting at the top of the dome to be seen during restoration. A total of five layers of safety netting will be used for the rotunda work.

This phase of the project will focus on paint analysis, abatement and restoration of areas stained by moisture that leaked through the dome. None of the murals in the rotunda have suffered moisture damage and they will not require restoration.

Just as the skirt project helped inform the current restoration efforts, Angba says aspects of the current project will resonate in future work.

"There are a lot of lessons learned both from a tech perspective and in terms of the work performed," he says. "What we'll carry on to future projects are the management aspects, particularly the use of collaboration."