North Carolina Legislative Building Restoration Poses Unique Challenges

The North Carolina State Legislative Building was the site of a renovation project that included asbestos abatement in the interior and a complete restoration of the building’s roof systems.

The North Carolina State Legislative Building was the site of a renovation project that included asbestos abatement in the interior and a complete restoration of the building’s roof systems. Photos: SkySite Images

Some of the variables that can make a project difficult include a variety of complex, interconnected systems, unique design elements, and a tight schedule. These challenges are heightened on a highly visible, historic building, where the goal of keeping the design historically accurate must be balanced with making improvements to the structure and functionality of the systems. All of these elements and more were in play during the restoration of the one-of-a-kind roof on the North Carolina State Legislative Building in Raleigh, North Carolina. It took a talented team of design, engineering, and roofing professionals to bring the project to a successful conclusion.

Originally designed by architect Edward Durell Stone, the building has been the home of the state legislature since 1963, but water intrusion under its copper pyramids and at windows and doors on the promenade level precipitated a complete restoration project. Renovation work conducted in 2016 and 2017 included asbestos abatement in the interior and a complete restoration of the building’s roof systems.

The roofing phase of the project included removing and replacing the metal roof systems on the five copper-clad pyramids, as well as re-roofing the low-slope sections adjacent to the pyramids with a two-ply modified bitumen system. A liquid-applied waterproofing system was installed in the planter areas and under the pavers in the promenade section. The project also involved the removal and replacement of windows, doors, and skylights, as well as repairing and coating the concrete surfaces at the perimeter of the roof.

The design of the quilted flat lock copper panel system involved 17 different panel profiles. A false batten was added after the panels were in place.

The design of the quilted flat lock copper panel system involved 17 different panel profiles. A false batten was added after the panels were in place. Photos: SkySite Images

Companies involved in the project included Raymond Engineering, headquartered in Raleigh, North Carolina, which provided engineering and architectural services; Owens Roofing Inc., also located in Raleigh, which served as the general contractor on the roofing phase of the project and installed the low-slope systems; and The Century Slate Company, headquartered in Durham, North Carolina, which removed and replaced the copper roofs on the five pyramids.

Some of the key players in the project shared their insights with Roofing, including John Willers, a senior engineer with Raymond Engineering; Bert Owens, president of Owens Roofing; and Mike Tenoever, president of Century Slate.

“This is an iconic state building with a unique roof system which the owner and designer required to be aesthetically replicated,” Tenoever notes. “At the same time, some functionality and technical improvements were incorporated. This is a very high-profile project with a lot of complexity, particularly given the schedule. There were a lot of details compressed into a very short period of time.”

Design and Pre-Construction

Raymond Engineering conducted testing on the existing roofs and specified systems designed to match the originals and provide some necessary improvements, including added insulation and ventilation under the pyramids. Willers worked closely with Jason Mobraten, the senior architect on the project. “We provided the engineering and architectural services, beginning with design and then assisting with bidding and managing the construction phase of this project,” says Willers. “We engineered the copper roof, all of the detailing for the modified asphalt roof, and the detailing for the drainage, the pavers, and the sealants for the promenade.”

Crews from Owens Roofing removed the existing plants, media and drainage system from four 42-foot-by-42-foot fixed planters with skylights. After the substrate was cleaned and primed, a liquid-applied waterproofing system was installed.

Crews from Owens Roofing removed the existing plants, media and drainage system from four 42-foot-by-42-foot fixed planters with skylights. After the substrate was cleaned and primed, a liquid-applied waterproofing system was installed. Photos: SkySite Images

The schedule was an obvious challenge, as the majority of the work had to be completed while the legislature was in recess, and there were substantial financial penalties that would come into play if the work was not completed on time. “The client also required that the asbestos abatement be completed before re-roofing the copper-clad pyramids to avoid the risk of dislodging the asbestos-containing textured ceiling finish. However, doing the work in two phases allowed the asbestos contractor to get started while the rest of the job was designed and bid,” Willers states.

The building houses legislators’ offices, and it was open and occupied during construction, with the exception of the areas undergoing asbestos abatement. The schedule had to be carefully adjusted as the job progressed. “In addition to our role in monitoring the technical aspects of the construction, we closely monitored the construction phasing and sequencing, as it was directly driven by the schedule of the state legislature,” Willers notes. “We had to take a lot of care in developing the schedule and monitoring it.”

Willers and Mobraten knew that the details on this project would be crucial. “There were previously some issues where the copper and the low-slope membrane roofs met,” Willers says. “We detailed that very carefully so that we had redundancy in keeping that watertight.”

Extensive mock-ups of the copper pyramids were constructed and tested to ensure the quilted pattern could be exactly replicated while avoiding the leaks that plagued the existing structure.

Photos: SkySite Images

Photos: SkySite Images

As designers looked for ways to improve construction, they explored the design and construction of the quilted panels. “From a design standpoint, we wondered why we had this odd diamond-shaped pattern,” Willers recalls. “After we played with the dimensions a bit, we realized that if you fly over the building, from above all of those diamond sections look like squares.”

The key was to replicate the design with its false battens while avoiding leaks. “We were concerned about how to detail out the joining of the copper sheets that formed the diamond-shaped panels,” Willers says. “What had been done was susceptible to windblown rain getting in. We did two things differently: the little clips that supported these battens were secured by forming the clips with hooks that would be integral with the single-locked seams and soldering the clips to the top surface of the copper panels. Previously they were held in place by pop rivets, which went through the copper.”

The Secrets of the Pyramids

Century Slate was well prepared to tackle the copper roofing on the project. The company has been in business more than 20 years, and it specializes in historic restoration projects including slate, tile, wood, copper and other historical metals.

Crews from Century Slate removed the existing copper panels. The copper was salvaged and recycled.

Crews from Century Slate removed the existing copper panels. The copper was salvaged and recycled. Photos: SkySite Images

Tenoever knew the design of the original quilted flat lock copper panel system needed to be replicated exactly. “There were 17 different panel profiles, each within a very particular location within the roof’s quilted pattern,” Tenoever notes. “Proper placement of each different profile was essential to the whole system working correctly and looking like the original.”

The first step was to remove the existing copper roofs. “We tore off the entire system down to the deck,” Tenoever explains. “We then installed a semi permeable a vapor barrier, insulation, and a vapor retarder.”

Along with added insulation and Carlisle WIP 300HT self-adhering underlayment, crews also installed a vented nail base from Hunter Panels. “The Hunter Cool-Vent is a vented nail base that gets screwed down,” Tenoever says. “The goal was to have a breathable air cavity. All of the hip caps are actually vented to allow the air to get out.”

With the addition of the insulation and nail base, the roof was built up approximately 6 inches from the previous configuration. This added height necessitated changes in the custom flashing at the base of the pyramids but did not change the configuration of the copper panels.

In all, 22,500 square feet of copper panels fabricated by K&M Sheet Metal in Durham were installed. Each of the 17 different panels was labeled with a letter code. “When they were out at the site, we could just grab an A panel or a B panel, as needed, and bring them to that layout,” Tenoever explains. “Four of the pyramids were the same, and the center one was different, as that was the one that had skylights built into it.”

The areas between the pyramids were covered with a two-ply modified bitumen roofing system. Photos: SkySite Images

The panels feature flat-lock clips that were screwed down to the nail base. “It’s a typical flat seam panel system, and the panels interlock together,” says Tenoever. “You can see the batten panel above it, which is an aesthetic feature. The battens and the clips that held them were amazingly intricate, for what they were. They were cut out with a CNC machine and soldered onto the copper panels prior to installation. Later we came back and installed the batten system over the top.”

Century Slate built new curbs in the center pyramid for the new skylights, which were manufactured by Wasco. “The skylights were one of the last things to go on,” says Tenoever. “They were custom made because even though they look square, there isn’t a square angle on them.”

Custom copper flashings were installed at the bases. “One of the trickier parts for us probably would have been the tie-in of the modified roof, because Owens Roofing had to do their bit, and we were also replacing all of the wood blocking and everything all along the bottom edge before we could put our flashing on,” Tenoever recalls. “It took a lot of coordination between the two trades, but it all worked out.”

The Low-Slope Roof Systems

Owens Roofing served as the general contractor on the project and installed the low-slope roof systems. The company was established in 1986 in Raleigh, and focuses on commercial and institutional buildings, almost exclusively re-roofing. Much of its work is on historic buildings, so Owens was confident he could execute the project and complete it on schedule.

A scaffolding system offered secure roof access, but material had to be loaded and removed from one access point, so logistics had to be carefully mapped out.

A scaffolding system offered secure roof access, but material had to be loaded and removed from one access point, so logistics had to be carefully mapped out. Photos: SkySite Images

Crews from Owens Roofing installed 18,900 square feet of modified bitumen roofing from Soprema over concrete decks, including the areas between the pyramids. Tapered polyiso and half-inch DEXcell cover board from National Gypsum were installed using Duotack adhesive, followed by the two plies of modified bitumen membrane.

A liquid waterproofing system from Sika was specified for the large planter areas. Crews from Owens Roofing removed the existing plants, media and drainage system from four 42-foot-by-42-foot fixed planters with skylights. After the substrate had been cleaned and primed, the Sika RoofPro system was installed.

“Once it’s cleaned and primed, it’s pretty simple,” says Owens. “The product is one part, and you don’t even have to mix it. We applied it with rollers on this project. You embed fabric sheets in the system and then topcoat it. It was a cold-weather job, but fortunately we caught a break last winter in that it wasn’t as cold as usual, and we didn’t miss as much time as we might have.”

The 30,000-square-foot promenade section was originally covered by white granite pavers native to North Carolina. The old pavers were removed and replaced over a new roof system, which was comprised of modified bitumen sheets beneath the liquid-applied waterproofing system. “The concrete deck was primed and a modified bitumen base ply heat welded to the deck,” Owens explains. “This surface was primed in preparation for the Roof Pro system, which was then installed.”

Innovative Roof Services of Raleigh was called in to conduct a high-voltage electrical testing to ensure there were no voids in the system before the pavers were re-installed. The pavers had originally been set in a bed of mortar, and they had to be removed and cleaned, which revealed a problem. “When we took the pavers up, we found out that they ranged between 1-1/8 and 1-3/4 inches thick,” Owens notes. “That wasn’t a problem when they were set in a bed of mortar, but over extruded polystyrene, they would have been all up and down. We put in a change order and had the pavers set in a bed of sand on top of one layer polystyrene.” The sand was adjusted by hand to ensure the pavers were level. New pavers were added to replace those broken over the years.

On the roof’s concrete eyebrows, damaged areas of concrete were repaired, joints were sealed, and a cold-applied waterproofing system from Sika Sarnafil was used to cover 8,800 square feet of concrete.

Numerous Challenges

Important considerations on the project included safety and logistics, as well as the tight schedule. Safety was paramount, and a third-party safety monitor was on the site to ensure the safety plan was designed and executed properly. During the time between when the original skylights were removed and when their replacements installed, the voids in the roof deck needed to be cordoned off and covered according to OSHA regulations. Personal fall arrest systems were used on the pyramids and outside of the safety perimeter, which was marked with flags. “With the promenade, you had a wide concrete eyebrow, so it made it easier to set up the safety lines and keep everyone safely away from the edge,” Owens notes.

This aerial photo taken before the restoration project shows the copper roofs with their green patina. Photos: SkySite Images

“Safety is a key concern as on all jobs, but this one in particular was highly visible out the windows of the nearby Department of Labor,” Owens continues. “We were paid a courtesy visit and agreed with them that an on-site safety meeting conducted by their personnel might be useful. The owner allowed us use of one of their auditoriums and we had a very productive half-day meeting for all trades. Every week we had a meeting with a state construction monitor.”

A scaffolding system was set up that offered secure roof access, but there was only one point for loading and unloading material, so logistics at the site were a concern. “We had to use wheelbarrows and roof carts to transport materials back and forth to the scaffolding tower,” Tenoever notes. “Between the removal of the original roof and the installation of the multiple layers of the new roof system, over 150,000 square feet of roofing materials were moved by hand over an average distance of approximately 200 feet.”

Loading and unloading added another wrinkle to the complicated schedule. “The schedule was based on when the legislature was scheduled to come back to town—not how long the job was supposed to take,” Owens says. “We were all concerned with the ambitious time frame and $1,000 a day liquidated damages included with this job.”

Willers cited excellent communication as one of the keys to completing the project on time. “Fortunately, the project managers for the general contractor and other trades were highly organized individuals,” Willers says. “Regular site meetings were detailed and thorough. Although setbacks did occur, communication kept the ball rolling.”

The roof system on the building’s iconic copper clad pyramids was removed and carefully recreated, matching the original design while adding a vented cavity and increasing the thermal insulation. Photos: SkySite Images

A Unique Experience

Copper removed from the existing roof was salvaged and recycled, notes Willers, with the exception of a few pieces that

were cut into the shape of the state of North Carolina to serve as mementos of the unique project. “We’re very proud of the design and the outcome—and the assistance we got from all of the contractors involved,” Willers says. “We had some pretty heavy rains after the project was completed, including some high winds, and there were no leaks.”

Tenoever also looks back on the project with pride. “A one-of-a-kind roof system was custom built and delivered on schedule and with the owner and designer’s praises,” he says. “Taking something so amazing and restoring it to the beauty it originally had—we all get a kick out of that.”

TEAM

Design and Engineering Services: Raymond Engineering, Raleigh, North Carolina, RaymondLLC.com
General Contractor: Owens Roofing Inc., Raleigh, North Carolina
Metal Roofing Contractor: The Century Slate Company, Durham, North Carolina, CenturySlate.com
Leak Testing: Innovative Roof Services, LLC, Raleigh, North Carolina, IRS-LLC.net

MATERIALS

Metal Roof System
Copper: 20-ounce copper sheet metal
Vented Nail Base: Hunter Cool-Vent, Hunter Panels, HunterPanels.com
Underlayment: Carlisle WIP 300HT, Carlisle, Carlislewipproducts.com
Skylights: Wasco Skylights, Wascoskylights.com

Modified Bitumen Membrane Roof System

Membrane: Sopralene Flam 180 and Sopralene Flam 180 FR GR, Soprema, Soprema.us
Adhesive: Duotack, Soprema
Insulation: Sopra-Iso, Soprema
Cover Board: DEXcell, National Gypsum, NationalGypsum.com

Waterproofing System

Liquid Applied Membrane: RoofPro 641, Sika Corp., USA.Sika.com
Reinforcing Fabric: Reemat, Sika Corp.
Primer: Sikalastic EP Primer/Sealer
Extruded Polystyrene Insulation: Foamular 604, Owens Corning, OwensCorning.com

Roofing Torch Program Reduces Fire Hazards During Modified Bitumen Application

CERTA offers a certification program in which authorized trainers deliver behavior-based training to roofing workers who install polymer modified bitumen roof systems.

CERTA offers a certification program in which authorized trainers deliver behavior-based training to roofing workers who install polymer modified bitumen roof systems.

The latest market survey conducted by the National Roofing Contractors Association (NRCA) shows the use of polymer modified bitumen as a percentage of all new roof systems, installed both in new construction and re-roofing projects, comprises about 10 percent of the total low-slope market, according to members responding. The significance of that share of the market for polymer-modified bitumen also highlights the importance of proper training in the use of roofing torches, the most common method for installation of such systems.

Background

In 1986, the Midwest Roofing Contractors Association (MRCA), in conjunction with industry organizations, the Asphalt Roofing Manufacturers Association, and the United Union of Roofers, Waterproofers and Allied Workers, developed a curriculum to train roofing workers in the safe application of torch-applied roof systems. This program was named the Certified Roofing Torch Applicator, or CERTA, program.

In 2003, insurance industry representatives approached NRCA to address concerns about an increase of losses and incidents involving torching activities conducted by roofing workers. One prominent insurer experienced over $7 million in roofing torch-related claims in 2002 spread over more than 30 separate occurrences. The need for enhanced work practices and focused safety training to address torching activities became apparent, and NRCA arranged with MRCA to adopt and revise the nature of and deliverables offered by the CERTA program.

CERTA now offers a unique, comprehensive certification program in which authorized trainers deliver effective behavior-based training to roofing workers who install polymer modified bitumen roof systems. CERTA-authorized trainers undergo a rigorous full-day training session that includes classroom and hands-on instruction in propane safety, hazards related to torch use, proper techniques for safe installation of polymer modified bitumen, and development of training skills. Individuals who successfully complete all aspects of the program then are authorized to deliver training, under the CERTA protocol, to workers who qualify as certified roofing torch applicators.

MRCA continues to work with NRCA to make sure the program is up-to-date and uses the most effective procedures to develop authorized trainers and enhance the curriculum. Since its inception, roofing contractors who have trained their workers under CERTA generally have experienced fewer torch-related fires, injuries and property damage. Insurance industry claims also are a testament to the CERTA program success—the insurer that experienced over 30 torch-related claims in 2002 now can count such average yearly claims on one hand with a significantly reduced average yearly dollar loss.

Safety Specifics

Trainees in a CERTA class spend a great deal of time on some specific aspects of the use of roofing torches to install a polymer modified bitumen roof system. Those specifics have a direct correlation to keeping workers and others safe, and minimizing the likelihood of property damage. First, the CERTA curriculum focuses on the inherent danger of roofing torches and discusses assessing job hazards and establishing controls for torching operations. Details cover the proper personal protective equipment to minimize or eliminate exposure to burns and the critical need to handle propane properly and make sure equipment is in good condition.

Pre-job planning enforces the significance of determining the hazards unique to the particular worksite and developing the necessary controls to address those hazards. In addition to general working conditions and weather issues that may influence job site safety, specific hazards such as the presence of a combustible roof deck, roof penetrations, concealed attic areas and combustible flashing substrates are addressed and suitable controls are suggested and discussed. Also, attendees get comprehensive information on the types and ratings of fire extinguishers and how they are used most effectively along with the minimum CERTA requirements for appropriate fire extinguishers that must be on a roof. In fact, CERTA requires a fire extinguisher capacity far exceeding OSHA’s fire protection requirements during torch operations— two 4A60BC-rated fire extinguishers within 10 feet of torching activity.

Another important fire prevention protocol is the use of a fire watch system. The intent of the fire watch is that a dedicated individual is charged with inspecting the work area after the last torch, or other heat generating tool, is extinguished. Ordinarily, this is accomplished visually, but it can also be done more scientifically with the use of temperature sensing infrared thermometer. These are inexpensive tools that read the temperature of an area that the tool is pointed at and display the reading in degrees on the screen. The fire watch individual would shoot various specific locations where hot work was done—for example, at roof penetrations, flashings or field areas—noting the temperature for each spot. This procedure would be followed for the same spots a short time later, and if the temperature had increased, the possibility that a fire under the roof surface could be a source of the increased heat being generated would require further steps to determine the nature of the heat increase and the proper action to take.

Historically, many industries and building owners have required a 30-minute fire watch be maintained after the last torch or other tool has been extinguished. Under the CERTA protocol, a two-hour fire watch is demanded of a CERTA roofing torch applicator. The fire watch must be maintained not just at the end of the day but at other break times, such as lunch, so that fires do not start when workers may be away from the work area or inattentive during break times.

Another key element of training for the CERTA torch applicator involves installation techniques that are intended to reduce the likelihood of a fire being started. The techniques include specified thermal barriers to protect combustible roof decks and substrate protection for flashing installations, along with an alternative torching technique that minimizes the use of direct torching.

Certa Works

Installation of polymer-modified bitumen roof systems using propane roofing torches requires adherence to a number of safety procedures and an awareness of the hazards that workers may encounter. The CERTA program has a proven track record of enhancing the safe practices of roofing workers who install these systems and the roofing industry, building owners and the general public are all safer because of its development and use.

Photo: NRCA

NRCA Announces June 4-10 is National Roofing Week

The roof is an important component of every structure, yet it often is taken for granted until it falls to disrepair. To raise awareness of the significance of roofs to every home and business, the National Roofing Contractors Association (NRCA) has announced National Roofing Week will take place June 4-10.

National Roofing Week also promotes the good deeds of the roofing industry and stresses the value of professional roofing contractors and the importance of making informed decisions about maintaining or replacing a roof system. During National Roofing Week, NRCA encourages its members to participate by engaging in their communities and informing the public about the role roofs and professional roofing contractors play in every community.

NRCA also will be sharing its members’ stories through its various social media outlets, its Roof Scoop blog and “Professional Roofing” magazine. Members throughout the U.S. are encouraged to share their stories of charitable giving, crew and staff appreciation, and roofing projects with NRCA.

“Professional roofing contractors play a role in every community, and National Roofing Week provides the roofing industry the opportunity to demonstrate the importance of the work we do,” says NRCA Chairman of the Board Dennis Conway. “I look forward to sharing the roofing industry’s stories of professional excellence and charitable giving during National Roofing Week.”

In addition, NRCA members are encouraged to promote the importance of what a roof does by encouraging children to participate in NRCA’s 2017 Children’s Art Contest sponsored by A.C.T. Metal Deck Supply and the International Roofing Expo (IRE). The contest is open to children in grades 1-8 whose relatives work for NRCA member companies (all NRCA member companies are eligible). Entries will be accepted until April 14.

ARMA Names Winners of 2017 QARC Awards Program

The Washington, D.C.-based Asphalt Roofing Manufacturers Association (ARMA) has named three winners of its annual Quality Asphalt Roofing Case-Study (QARC) Awards Program. The program seeks contractors who choose asphalt roofing and install beautiful and high-performing systems. This year, a stunning home in North Carolina, a commercial building in Florida and a firehouse in Washington state have been chosen as winners.

Chapel Hill Roofing Co. received the Gold QARC Award for its residential project titled The Triangle Home. The North Carolina-based contractor installed a full asphalt roofing system to fit the home’s complex architecture and the homeowner’s desire for a range of color options, protection from the elements and algae resistance at an affordable price.

The Silver Award was given to Advanced Roofing Inc., Fort Lauderdale, Fla., for the second year in a row. Its completion of a 49,955-square-foot roof on the Broward County Addiction Recovery Center’s Stephen R. Booher Building impressed judges with its intricacy. The new high-performance roof system provides weatherproof protection for the building’s residents.

Cascade Roofing Co., Burlington, Wash., was honored with the Bronze QARC Award for its steep-slope installation on the Burlington Fire Department firehouse. The building needed a new roof and required a product that had visual appeal, wind resistance and algae resistance. Cascade Roofing installed a full asphalt roofing system, including a synthetic underlayment and an ice and water shield on the leading edges.

ARMA received a record 40 submissions this year. These projects demonstrated the range of colors and designs that asphalt roofing can achieve, its ability to meet challenging project requirements and to provide reliability in tough climates. Each year, these projects are judged by a panel of roofing industry experts from trade associations, architecture firms and the media. Judges score projects based on their use of asphalt roofing technology to provide curb appeal, durability and value.

“As the QARC Awards Program has expanded over the last seven years, it has grown increasingly challenging for our judges to choose from the numerous excellent projects we receive,” notes Reed Hitchcock, ARMA’s executive vice president. “This year, it came down to identifying which projects demonstrated how contractors use asphalt roofing to solve key challenges for building owners and to provide peace of mind with a protective roof system.”

For more information about the QARC awards projects, visit the web page.

RoofPoint Administration Transfers to Roofing Industry Alliance for Progress

The Roofing Industry Alliance for Progress announces the administration of RoofPoint has been transferred to the Alliance. RoofPoint is a voluntary, consensus-based green building rating system that provides a means for building owners and designers to select nonresidential roof systems based on long-term energy and environmental benefits.

Originally developed by the Center for Environmental Innovation in Roofing and co-sponsored by the Alliance, RoofPoint is a roofing-specific version of a green building rating system that promotes an environmentally responsible built environment.

“The increasing need for energy efficient and environmentally friendly roof systems makes RoofPoint an important component of our industry,” says Alliance president, James T. Patterson C.P.M of CentiMark Corporation, Canonsburg, Pa. “We are pleased to have the opportunity to manage RoofPoint, and to continue the essential role it plays in promoting environmentally sustainable buildings.”

To ensure a smooth transfer of RoofPoint to the Alliance, a task force has been established to examine RoofPoint’s data and determine next steps.

Task force members are Rob Therrien, president of The Melanson Co. Inc., Keene, N.H.; Helene Hardy-Pierce, vice president of technical services, codes and industry relations for GAF, Parsippany, N.J.; Brian Whelan, senior vice president of Sika Sarnifil Inc., Lyndhurst, N.J.; Jim Barr, president of Barr Roofing Co., Abilene, Texas; and Mark Graham, vice president of technical services for the National Roofing Contractor Association (NRCA), Rosemont, Ill.

The task force will present its recommendations to the Alliance Board of Trustees during its Nov. 17 meeting in Chicago.