A case of honorable roofing

United Materials renovates the Byron R. White U.S. Courthouse's roof systems

The Byron R. White U.S. Courthouse in Denver is an excellent example of neoclassical architecture that dominated federal building designs at the turn of the 20th century. Currently the seat of the U.S. Court of Appeals for the 10th Circuit, the 244,000-square-foot building's four stories and two basement levels occupy an entire city block.

Set on a pedestal and surrounded by sidewalks, the courthouse is clad in white Colorado Yule Marble. The front exterior is faced with a three-story portico of 16 Ionic columns; the other three sides feature pilasters with Ionic capitals and the national coat of arms. Barrel-vaulted ceilings and notable artwork, including a pair of limestone Rocky Mountain sheep sitting at the southwest entrance, create a dramatic display of architecture and history.

Completed between 1910 and 1916, the building also houses a post office. The frieze above the main entrance has city names symbolizing the flow of mail across the U.S. The solid marble walls on either side of the colonnade are inscribed with the names of former U.S. postmasters general. Inscribed on wall piers are Pony Express riders' names, including Buffalo Bill Cody, an important part of U.S. Postal Service history.

In 1973, the building was listed on the National Register of Historic Places. In 1994, it was dedicated the Byron R. White U.S. Courthouse in recognition of a man whose contributions as a Supreme Court justice made a lasting impression. In 2011, United Materials LLC, Denver, made significant roof system repairs to the courthouse.

A plea to save money

For the past 68 years, United Materials has reroofed and maintained many aspects of the Byron R. White U.S. Courthouse, so the company is familiar with the building's architectural complexities. Completely reroofing the building would have cost taxpayers $7 million, but United Materials crafted a plan to make roof system repairs that cost about $700,000, an annual taxpayer savings of about $280,000.

United Materials' plan to renovate the Byron R. White U.S. Courthouse's roof systems included applying 61 squares of Johns Manville's DynaKap™; resecuring and repairing slate and asbestos fiber-cement shingles facing the inner building; reroofing low-slope areas with Johns Manville's DynaBase® and DynaKap with cold adhesive; replacing all leading ledges with GAF's EverGuard® TPO; repairing or replacing metal counterflashings; designing and installing Occupational Safety and Health Administration-compliant and General Services Administration's (GSA's) historical expert fall-protection anchors and lifeline system; and performing necessary maintenance to interior DERBIGUM® courtyard well roof systems.

Logistical challenges

During the early 1900s when the Byron R. White U.S. Courthouse was being built, geographical inconveniences were limited. During 2011-13, United Materials' roofing work required careful and complex execution of a plan incorporating space availability, parking, public safety, materials staging requirements and tight security.

To access the building to perform work, streets and parking spaces needed to be blocked off; city sidewalks were fenced off; safe egress had to be provided to pedestrians; and materials needed to be loaded to the work site after business hours or on weekends. For 14 months, work was confined between the hours of 6:30 a.m. and 5 p.m., five days per week through the seasons.

From a security standpoint, the project was a high-priority, highly secure job, beginning just after the 10th anniversary of 9/11. Around this time, special attention was given to federal government buildings that had been prey in the past to domestic or foreign terrorist entities, making the job site consistently tense. Federal marshals with bomb dogs needed to be retained, trucks were inspected, and every worker needed to obtain a high-security clearance accompanied by a badge that had to be displayed at all times.

Additionally, only one United Materials worker was allowed to bring in a mobile phone; no other mobile devices were allowed on-site, and all tools and equipment needed to be examined at a security checkpoint and cleared through a metal detector. The coordination between multiple layers of law enforcement running through different jurisdictions was complicated. The communication network regarding project progress expanded beyond law enforcement entities such as U.S. marshals and included building owners, GSA representatives, GSA public divisions and the GSA construction department. Through careful planning, United Materials coordinated communication among all parties.

An improved safety design

Navigating on and around a courthouse built in the early 1900s poses certain safety risks not part of modern architecture, but the need to anchor roof technicians for building repairs remains the same.

United Materials designed a new safety system for the courthouse that is nearly invisible and allows technicians to be anchored while performing work. Eight anchors made of heavy-duty steel with the capacity to handle 5,000 pounds were fastened to the building with moisture-curing construction adhesive, and plates were adhered to the concrete deck with a urethane construction adhesive and through-deck bolts. Minimally exposed near the roof's crest, the anchor shrouds were designed to look like vent stacks and powder-coated to match the existing asbestos fiber-cement shingle roof system.

Visually from the ground or from neighboring buildings, the anchors and their shrouds appear integrated. A key aspect of properly anchoring the technicians was to be able to make repairs to the slate units used as roofing and wall cladding, which measure 24 by 36 inches and weigh about 80 pounds each. The safety system allows two roof technicians to be anchored in the same place for greater efficiency. Slate repairs were made with adhesive and attached with copper wires. The repairs aren't visible and are expected to last about 30 to 40 years.

The newly integrated safety system cannot be seen from neighboring buildings, is permanent and does not require maintenance. It is GSA-certified for long-term use by all GSA contractors. United Materials also created a user manual for the new system to be used by the building owner.

A solemn workspace

To say matters of life and death are part of the daily work inside the Byron R. White U.S. Courthouse is not an overstatement. Essentially, United Materials needed to be invisible as matters of justice were carefully dispensed. Respect to the environment was crucial. Carpets, marble and stairways needed to be protected, and fumes had to be eliminated. United Materials employees often worked in attics to perform repairs around 80-year-old heating systems.

Additionally, given the nature of irreplaceable resources such as lead glass, United Materials could not afford to break anything and was responsible for protecting the integrity of an interior courtyard where the roof above was being repaired. While judges took respite in a secured courtyard, United Materials technicians were five stories above, secured to the building making repairs.

To complicate matters, most of the drainage material was corrugated galvanized pipe inside granite walls, all encapsulated. If a leak occurred as a result of a mishap, it would have occurred between asbestos-containing plaster on the inside walls and granite on the outside walls. Great care was exercised to make repairs correctly the first time because there was no room for error.

Tending to the details

The courthouse's perimeter and flashing details all were custom-designed and didn't allow for any mechanical fastening. The granite is weight-supported, similar to the design and construction of a pyramid. United Materials strived to incorporate and reuse some of the design details it used 18 years ago when it engaged in a different remediation courthouse project.

Repairs were made to the "widow's walk" on the low-slope roof system. The 36-inch-tall cast-iron railings were sagging and had to be removed to weld and rebuild. Once the rails were welded and rebuilt, they also were powder-coated and reinstalled. It was important for United Materials to take the significance of the historical aspect of the architecture into account and return the materials in better condition than when they were found.

"The project presented elements typical in an historical building project," says Beth Gloss, managing member of United Materials. "With a mix of materials such as tapered insulation, polymer-modified bitumen and single-ply membranes, United Materials dedicated itself to work around the various roof systems without disturbing historical details."

When installing a new tapered insulation system, United Materials tied in all new metal counterflashing details. About 30 to 35 percent of the work was done using adhesives because mechanical fasteners were not allowed given everything was buttressed in with weight. Instead of manufactured standard details, United Materials had every detail custom-built, resulting in modern craftsmanship that matches historical integrity.

The verdict is in

When United Materials completed the project in January 2013, more than 60,000 square feet of roofing materials were maintained, repaired or replaced. United Materials completed the project on time, on budget and accident-free. To date, the courthouse roof systems have not had any leaks or defects.

"The most rewarding part of the job is knowing GSA continues to entrust United Materials to take care of the Byron R. White U.S. Courthouse's roof," Gloss says. "Our continual strong relationship with GSA and its dependency on our expertise is a huge responsibility, but our satisfaction is in knowing we keep an important part of history in watertight condition."

For its exceptional work on the Bryon R. White U.S. Courthouse, United Materials received a 2014 Gold Circle Awards honorable mention in the Outstanding Workmanship: Low-slope category and was awarded a 2013 RoofPoint™ Excellence in Design Award in the Excellence in Reroofing category from the Center for Environmental Innovation in Roofing.

Chrystine Elle Hanus is Professional Roofing's associate editor and NRCA's director of communications.

Project name: Byron R. White U.S. Courthouse
Project location: Denver
Project duration: September 2011-January 2013
Roof system types: EPDM; SBS polymer-modified bitumen; slate
Roofing contractor: United Materials LLC, Denver
Product manufacturers: DERBIGUM,® Kansas City, Mo.; GAF, Wayne, N.J.; Johns Manville, Denver
Gold Circle Awards category: Outstanding Workmanship: Low-slope



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