The State of Colorado–State Capitol Dome Restoration

The state began to take action after a piece of cast iron from the dome broke loose and landed on a deck below. After a forensic investigation, the state retained GH Phipps Construction Companies and a team of architects and consultants to devise a plan that would abate, clean, preserve and restore/repair the integrity to the dome structure. It was decided to address each cast iron element; remove lead-based paint from a century ago and replace it with contemporary, durable paint; restore or replace ornamental sheet metal accents and gutters; replace the copper roof substrate under the gilded dome; remove asbestos; restore the lantern atop the dome; install a lightning protection system; remove and restore historic windows, and, ultimately, regild the dome.

The work was accomplished by erecting a scaffold “cocoon” that eventually
reached 22 levels and was designed to meet vertical loading points and horizontal points for wind loading. The protective scrim was designed to
peel off in 60 mile per hour winds in order to avoid over- loading the existing
structure. A digital point cloud was created to coordinate the actual shape
and dimensions of the existing dome with the design of the scaffolding to
avoid conflicts. The scaffold provided containment for the lead paint and
asbestos removal and offered access to the restoration work, and had to
rest on precise locations on the roof that were shored into specific locations
of the existing structure inside the attics. The project was phased, and the
Capitol remained occupied during construction.