DMS were invited to do the cost estimation for the restoration of both the exterior and interior of the iconic Dome at the United States Capitol Building.

The history

It’s impossible to miss the spectacular Capitol Dome in Washington – a beacon of inspiration first designed by Thomas U. Walter and constructed between 1855 and 1866. The Dome is situated above the United States Capitol Building, reaching upwards to 288ft in height and 96ft in diameter.

The project

A project of great precision, with a number of logistical elements to be considered such as the highly occupied, public nature of the building as well as its historic significance, the first quotes began in 2007 and phase 1 was carried out in 2012. 

Careful measures had to be taken for the particular challenges of this project.  In particular, as a tourist attraction all works had to be done at night, public safety was a priority and at the end of each working ‘day’ the area had to be thoroughly cleaned to allow for tourists to return, limiting the working hours. 

Of course, the project required scaffolding around the exterior of the Dome, and a safety-netting system was also suspended inside the Rotunda.  The project also required the majority of works to be done by hand such as the removal of old paint and repainting.

Eventually taking four months to complete, the Dome that once oversaw President Lincoln’s first inauguration whilst undergoing its initial construction, was returned to its former glory and today continues its iconic role in American history

Types of work carried out

Having last undergone major repair work in 1960, the cast-iron Dome was suffering from the effects of weathering and ageing including corrosion and cracking.  Cracked columns were typical of the condition of deteriorating parts of the Dome, which was plagued by more than 1000 cracks and deficiencies.

Cost estimation

The cost estimate for this project involved individual elements that were removed and repaired, the historical cast-iron elements were restored, the exterior was weatherproofed, broken windows were replaced, and hazardous materials were removed as was the old lead-based paint from the entire Dome skirt, which was replaced with protective new coatings and seams.

Estimated construction cost: $4.7million.