Built on land once used for John Hancock's cow pasture, Boston's Massachusetts State House is a symbol of American history with ties to founding fathers and Revolutionary War heroes. The first cornerstone was laid July 4, 1795, in a grand ceremony led by Gov. Samuel Adams accompanied by Paul Revere.
The golden dome, the building's most distinctive feature, once was made of wood and later overlaid with copper by Revere Copper Products Inc., Rome, N.Y., founded by Paul Revere in 1801. It was the first application of cold-rolled copper in North America. During World War II, the dome was painted black to prevent reflection during blackouts and protect the city and building from bombing attacks. In 1997, the dome was regilded in 23-karat gold. A wooden pinecone adorns the top of the golden dome as a symbol of the state's reliance on logging during the 18th century.
Currently, Massachusetts State House is one of the oldest buildings on Beacon Hill, and its grounds span two city blocks (6.7 acres). Under the golden dome, senators, state representatives and the governor conduct daily business of the Commonwealth of Massachusetts. In addition to its fundamental functionality as a political hub, it is considered to be a living museum and one of the most important historical buildings in New England.
Leaking evidence
The roof system on Massachusetts State House was leaking and in disrepair for many years. Water was entering the historic building in alarming quantities. In 2006, the Division of Capital Management commissioned engineering firm Simpson, Gumpertz & Heger Inc., Waltham, Mass., to determine the extent of the damage and scope of replacement. The Commonwealth of Massachusetts solicited requests from roofing contractors to bid on the public-sector project, and Greenwood Industries Inc., Millbury, Mass., was selected for the $4.6 million project.
"Getting a job of this size is a dream for a lot of our guys," says Bob Sparks, Greenwood Industries' project foreman. "It's like a mason being able to work with marble. You might never see a job of this magnitude again."
On June 5, 2009, Greenwood Industries commenced work on eight distinct areas of work:
Memorial Hall: Memorial Hall is covered by a pyramid roof and walls originally clad with about 4,000 square feet of flat-seam 20-ounce cold-rolled copper. Greenwood Industries removed the existing flat-seam construction and replaced it with a combination of flat- and standing-seam cold-rolled copper roof and wall panels. All copper for the project was manufactured by Revere Copper Products and fabricated by Greenwood Industries.
House of Representatives Chamber Dome: The existing roof system consisted of steep- and low-slope flat-seam copper panels that leaked so much they were covered with EPDM painted green to match the appearance of patina copper. This area also contained a radius gutter and a four-sided hip roof structure with existing cold-rolled copper standing-seam panels. All areas were stripped to the existing wood plank. The rotted wood deck was replaced and covered with Grace Ice & Water Shield.®
About 4,500 square feet of flat-seam 20-ounce cold-rolled copper panels were fabricated off-site, pretinned, hoisted to the roof, installed with clips and fully soldered. A new Siplast® polymer-modified bitumen membrane was installed on the low-slope areas. Custom 32-ounce cold-rolled copper built-in gutter liners were fabricated off-site and hoisted into place. The gutter was assembled like a jigsaw puzzle in the field and soldered. Expansion joints were added to the original design to prevent cracking of the solder joints. The hip roof structure received a new 20-ounce cold-rolled copper standing-seam metal roof system. For worker safety, a complete safety rail system with netting was built and installed.
Penthouses: Massachusetts State House has eight penthouses. The roof systems varied between Siplast polymer-modified bitumen, flat-seam cold-rolled copper roof panels and standing-seam cold-rolled copper metal wall panels. The existing copper was removed and new plywood was installed to the existing concrete masonry unit as a substrate for the new 20-ounce cold-rolled copper panels. The penthouses stand 30 feet above the primary roof structure and were staged with back rails; employees were required to work in harnesses tied off 100 percent of the time.
Bullfinch portico: A major focal point of Massachusetts State House is the bullfinch portico located above the front entrance and directly below the gold dome. The existing roof system was EPDM over a concrete deck surrounded by railings and balustrades. Greenwood Industries removed the existing roof system and worked with the general contractor, J.K. Scanlan Co. Inc., East Falmouth, Mass., to rebuild the existing railing flashed with copper. Next, Greenwood Industries installed a Sika Sarnafil fully adhered PVC roof system over tapered insulation then covered the roof with sand-coated PVC walkway pads. The roof was flashed into the new railing systems and tied into the abutting, existing slate.
Cooling tower: In this area of the building, the steel supports for the cooling system were less than 18 inches above the existing roof system. The area consisted of wood plank, plywood, steel and concrete decks. A section of the roof area originally was interior office space but later converted to accommodate cooling equipment. The area was not accessible by crane, so the existing EPDM roof system, pavers and rotted deck were removed and transported by hand through the building, down a freight elevator and to the trash bins. New 3/4-inch-thick plywood was installed as necessary to create the substrate level. Next, Greenwood Industries installed a Sarnafil Sarnavap self-adhering vapor barrier and a layer of Georgia-Pacific DensDeck® followed by a Sarnafil 60-mil-thick mechanically attached PVC membrane.
Porticos: Massachusetts State House has five patio-type portico roof systems. Four porticos are integral parts of the legislative offices, including the office of Senate president, speaker of the house, clerk of the Senate and House lobby. The fifth portico is part of the Library of State Legislature. The existing porticos consisted of a concrete substrate covered by a polymer-modified bitumen waterproofing membrane and blue stone pavers set in a cementitous base.
The pavers were removed by jackhammer and lowered to the ground by crane along with the concrete debris and waterproofing. A Sarnavap vapor retarder was installed over the existing concrete roof deck and covered by loose-laid tapered extruded polystyrene and Sarnafil 80-mil-thick PVC membrane with fleece backing. All flashings were constructed with Sarnaclad PVC-coated metal and hot-air welded to the roof system. Hanover® Architectural Products' pavers were installed on pedestals to form a fully functional patio.
Access was provided from the building's exterior by a 110-foot snorkel lift. The active offices adjacent to the porticos continued work without interruption. Workers used a railing system and full-body harnesses tied off in the lift and during railing installation.
East and west wings: Greenwood Industries removed an existing asbestos-containing built-up roof system covered by EPDM and full pavers using workers certified to handle asbestos-containing roofing material. The roof area consisted of a 6- to 8-foot alleyway surrounding the east and west wings. The alleyway has a parapet wall and railing on the building's exterior and a standing-seam wall panel with windows every 4 feet housing private offices for legislature staff.
The new roof system consists of 3-inch extruded loose-laid polystyrene covered with a Sarnafil 80-mil-thick PVC membrane with fleece backing, pavers and pedestals. Working with the window contractor, Greenwood Industries installed new windows with flashings into the existing standing-seam wall panels.
Lastly, snow guards were soldered on the exterior cornice shelf, which is 1 to 2 feet wide and sits about 100 feet above the ground. All work was performed with limited interruption to the interior offices.
Main roof: The main roof system consists of the south, central and north sections. The three sections consisted of the same existing flat-seam cold-rolled copper system. A majority of the main roof leaked and was replaced with standing-seam 20-ounce cold-rolled copper. Low-slope areas were replaced with a flat-seam 20-ounce cold-rolled copper roof system, and the joints and seams were fully soldered in place.
A built-in gutter surrounds the building's entire exterior. The existing gutter and substrate were removed, reframed and rebuilt. Simpson, Gumpertz & Heger determined the sections to receive a 32- or 20-ounce copper liner based on the gutter's geometry. The 32-ounce copper liner was field-measured and shop-fabricated in 20 sections. Custom crating was designed and fabricated to allow for the gutter liner to be hoisted to the roof. The 20 sections were numbered according to the field measurement because each piece was different. The pieces were assembled and soldered in place using copper locking strips.
The standing-seam copper panels were roll-formed at Greenwood Industries' shop in lengths from 12 to 48 feet. Custom crating was designed and built to allow for trucking to the site and hoisting to the roof. The main roof consists of 21,900 square feet of standing-seam cold-rolled copper panels and 7,000 square feet of flat-seam cold-rolled copper panels. Additionally, the main roof has 15 skylights, each of which required the fabrication and installation of custom flashing and crickets. A new snow-retention system was designed and installed along with a permanent fall-restraint system.
The interior roof section has internal drains that surround the Great Hall of Flags, the newest interior addition. The existing roof system consisted of EPDM and cold-rolled copper panels. Both were removed, and a 13,100-square-foot Siplast cold-applied two-ply polymer-modified bitumen roof system was installed over mechanically attached 2-inch-thick polyisocyanurate and 1/2-inch-thick fiberboard.
Cross-examining challenges
In addition to eight roof systems, the project's location also presented major obstacles. Boston is a highly congested urban center, and the site did not allow for storage of materials on the ground. Only four parking spots along the adjacent roadway were allotted to Greenwood Industries. When materials were needed, a truck delivered the supplies that were lifted by crane to the roof and immediately hoisted. Crane days needed to be planned well in advance, and all crane activities needed to be performed the same day material was delivered to the job site. All construction waste was hoisted off the roof and transported in the same fashion.
The Commonwealth of Massachusetts conducted its daily operations while Greenwood Industries performed its work. Through careful planning and coordination with J.K. Scanlan and other subcontractors, no intrusions or obstacles were presented to the building's occupants.
Additionally, every day hundreds of tourists visit Memorial Hall—a memorial to those who fought and died during the Civil War—and it remained open throughout the construction's duration.
Asserting exemplary craftsmanship
Every sheet metal worker performing soldering on the project was required to be tested and certified by Simpson, Gumpertz & Heger. In addition to exemplifying superior workmanship, the workers endured extraordinary weather conditions. Through the project's duration, the ambient temperatures on the job site ranged from below freezing during winter months to 100 F during the summer with roof surface temperatures exceeding 135 F.
"Work progressed during snowstorms in winter and during the hottest days of the summer," says Tom Shevory, project manager at J.K. Scanlan. "It was evident the men showed pride in their work, which is now portrayed in the beautiful copper roof that protects the state house."
Although temperatures presented obstacles at times, the tedious soldering tasks were performed by hand. While installing the snow guards, workers meticulously soldered them with only a clearance of 1 1/2 feet to work. Much of the copper cladding and transitions from copper to slate also were performed by hand during extreme weather conditions.
"The roofing and sheet metal workers from Greenwood Industries showed tremendous dedication to their craft," Shevory says. "These men ensured every proposed detail was vetted before being implemented, every seam was soldered properly and every joint properly sealed."
An appealing success
On April 30, 2011, a majority of the reroofing project successfully was completed nine months ahead of schedule and under budget. Greenwood Industries removed about 83,600 square feet of flat-seam copper panels, standing-seam copper panels, EPDM, built-up roofing, pavers and waterproofing and installed 18,400 square feet of Sarnafil PVC membrane, 9,400 square feet of pavers and about 46,000 square feet of copper.
"The Massachusetts State House roofing project tested the limits of the art of historic roof system replacement," says David Klein, president of Greenwood Industries. "Greenwood Industries not only met the challenge but also was able to exceed project goals."
For its work on Massachusetts State House, Greenwood Industries received three NRCA Gold Circle Awards—Winner, Outstanding Workmanship: Steep-slope; Honorable Mention, Outstanding Workmanship: Low-slope; and the Platinum award for presentation of its work.
Chrystine Elle Hanus is Professional Roofing's associate editor and NRCA's director of communications.
Project name: Massachusetts State House
Project location: Boston
Project duration: June 2009-April 2011
Roof system types: Copper; polymer-modified bitumen; PVC
Roofing contractor: Greenwood Industries Inc., Millbury, Mass.
Product manufacturers: Georgia-Pacific Gypsum LLC, Atlanta; Grace Construction
Products, Cambridge, Mass.; Hanover Architectural Products, Hanover, Pa.; Revere
Copper Products Inc., Rome, N.Y.; Sika Sarnafil, Canton, Mass.; Siplast, Irving,
Texas
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