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Local Pride

PROJECT
Idaho State Capitol, Boise, ID

ARCHITECT & ENGINEER
CSHQA, a Professional Association, Boise, ID; John Maulin, principal in charge

ARCHITECTURAL ASSISTANCE
Isthmus Architecture, Inc., Madison, WI

CONSTRUCTION MANAGER
Jacobsen-Hunt Joint Venture, made up of Jacobsen Construction Company, Salt Lake City, UT, and Hunt Construction Group, Phoenix, AZ; John H. Emery, senior project manager

By Hadiya Strasberg

In 1905, nineteen architecture firms submitted designs in the competition to design the Idaho State Capitol. While the firms hailed from across the U.S., the commission ended up selecting a local one, John Tourtellotte and Company. A century later, when the capitol was in need of repair, another Boise-based firm – CSHQA, a Professional Association – was chosen to carry out the restoration.

Tourtellotte conceived of the capitol as "one of exquisite light." His crowning achievement was a 208-ft.-high windowed dome that, along with light shafts, skylights and reflective marble surfaces, captured natural light to illuminate interior spaces. From 1905 to 1912, the dome, central rotunda and central office area were built. The east and west wings, which housed more office space as well as chambers for both the House and Senate, were constructed from 1919-1920.

In the 1950s and 1970s, the capitol suffered interior modifications unsympathetic to Tourtellotte's original design. "The intent was to make the building more usable as an office building for the state government," says John Maulin, principal in charge at CSHQA. "Unfortunately, much of this work damaged the historic fabric of the building."

"These remodels were not kind to the building," adds John H. Emery, senior project manager at Jacobsen-Hunt Joint Venture. "Six- to 8-ft. drop ceilings were added to hide new electrical and mechanical systems, concealing original ornamental plaster and millwork. Plaster, marble, and millwork were cut through to make way for conduit, wire, pipe and ductwork."

When CSHQA and Jacobsen-Hunt were brought onboard for the restoration – which was carried out between February 2007 and November 2009 – the building required a new roof, new systems, and the restoration of the stone, marble and wood flooring, windows, doors and hardware, decorative plasterwork, and light fixtures. Two 25,000-sq.ft. underground buildings were added to the basement to provide more offices and hearing rooms.

"Our philosophy was to restore the Idaho State Capitol back to its original glory as closely as possible," says Maulin. Emery adds, "Wherever possible, we reused existing materials. When elements were beyond repair, we did our best to match the materials, such as the sandstone, marble, wood and hardware."

Sandstone, which makes up the majority of the exterior, was an easy match as it came from the Table Rock quarry nearby. The marble was another story. Nine types of marble had been used on the interior, including a red from Georgia, gray from Alaska, green and gray from Vermont, and grays from Italy. Of these, only the red was matched nearly exactly. "We found old blocks of ruby red that were quarried from the original source in Georgia," says Emery. "They had been rejected due to size and content, but we were able to capture enough to complete the red border."

As for the green Vermont marble – used for the wainscoting and walls – the quarry is now almost a mile into the mountain, but in the early 1900s it was quarried near the surface, so the color and graining varied slightly. Likewise, for the gray and white marble, "we selected near matches," says Maulin.

The wood was a slightly different case, as the team focused on removing wood elements unoriginal to the building as well as trying to match the original wood. "Various additional types of wood, such as oak and black walnut, had been added during past renovations," says Maulin, "so we removed those." The original Honduras mahogany and mahogany-stained birch elements – trim, details and doors – were restored with Dutchmen repairs, and multiple wood stains were sampled on several different species of mahogany to achieve an appearance closest to the original.

During the mid-20th-century renovations, some of the windows were replaced with insulating glazing units installed in the existing frames. The latest restoration replaced all the exterior window sashes with appropriately matched insulated window sashes utilizing the existing casings. "We turned to North Kansas City, MO-based Re-View to replicate the original window design with double-paned windows," says Emery. "Re-View applied computerized wood fabrication and customized tools to bring the new windows up to today's thermal-barrier standard."

For some of the windows and skylights, historical glass was replicated. "Glass proved to be one of the most difficult materials to find," says Maulin. "The capitol has a diamond-patterned chicken-wire glass, which is no longer manufactured in the size or quantity that was required for many of the skylights and various high windows." In place of the chicken-wire glass, CSHQA specified a laminated window glazing with embedded chicken wire that was a near match.

Another hard-to-find material – or application – was scagliola, which adorned the eight grand Corinthian columns in the rotunda, the 32 Doric and Corinthian columns on the third and fourth floors and the columns in the Senate and House chambers. Over the years, the scagliola on these columns had been coated with a layer of yellowing shellac, stained with nicotine, and scratched and dinged. "Originally, we thought the scagliola was going to be difficult to restore and repair, because we weren't aware there were any U.S. contractors who specialized in that work," says Maulin. New York City-based EverGreene Architectural Arts, one of the few companies in the country that still works in this craft, used traditional techniques and materials to restore the milky-white scagliola, re-creating the look and feel of fine marble throughout the building.

The process of restoring the interior plasterwork was almost as painstaking. The team was committed to unveiling the ornamental plasterwork hidden under the drop ceilings and in other places around the building, but it was more challenging than the team aniticipated. Some plaster details were covered by a dozen layers of paint, including the original distemper paint. "The distemper paint was encapsulated by the many additional layers of paint," says Maulin. "Construction disturbed the painted surfaces, which caused the paint to lift from the walls and ceilings in areas where water had gotten under its surface." The construction crews had to hand scrub, scrape and grind the wall surfaces to eliminate the layers of bad paint. For some of the walls it was easier to apply a new layer of gypsum board than to clean the distemper paint.

Once the paint was removed, the plaster details and trim were restored or replicated. The most challenging aspect of this was coordinating the plasterwork, trim and millwork when smaller rooms were combined to meet the needs of the current occupants. "Separate rooms rarely had the same decoration," says Emery, "so our challenge was to make them appear as though they'd never been divided."

Plasterwork also included replicating nearly 975 plaster rosettes to comply with the lighting code. Approximately 160 light fixtures were preserved and restored; they were re-fitted with energy-efficient lamps and rewired to meet code and energy-saving goals. For various reasons, some of the original fixtures had been lost, removed or significantly damaged over time, which required 572 historically accurate replication fixtures from St. Louis Lighting of St. Louis, MO.

Other code and efficiency upgrades included the electrical, data communication, HVAC and life-safety systems. "Our goal was to return the building to its historical appearance, with up-to-date systems that didn't disrupt the architecture in any way," says Emery. To that effect, the new mechanical, electrical and fire-safety systems were hidden in walls and existing shafts.

One of the early modifications – the installation of a geothermal well in 1982 – was actually a constructive addition, and only a heat exchanger needed to be replaced during this project. According to the Environmental Protection Agency, a geothermal system operates at 75 percent greater efficiency than an oil furnace and 48 percent greater efficiency than a gas furnace. It boasts minimal environmental impact and superior indoor air quality. It also saves Idaho an estimated $500,000 in annual heating costs. The Idaho State Capitol remains the only capitol in the U.S. to be heated by geothermal water.

Another underground project was the expansion of the building. As the state population grew, so did the government, and even before 2007 the capitol was overcrowded. An addition was much needed, but contentious. To avoid modern additions that might obscure the Classical style of the original building, two 25,000-sq.ft. underground wings were conceived. Legislative hearing rooms, large mechanical spaces, data centers, kitchens and dining facilities were moved out of the main building and into the former basement. Office and meeting space was programmed for the Garden Level wings as well.

"It was important that the new Garden Level interior have the same look as the existing areas in the old building," says Emery. "The new construction includes the same marble, plaster and mahogany trim that made the original building so distinctive."

What is characteristic about the building will remain so for many years to come, thanks to the recent restoration. Two Boise architects – one in the early 20th century and one in the early 21st century – along with numerous construction managers, contractors and craftspeople, delivered the Idaho State Capitol to the people of Idaho. This time it is renewed and enlarged, while retaining the same style and beauty of the original building. TB

 

 

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