Restoring Natural Slate Roof Takes Expert Craftsmanship

Photos: Charles F. Evans Company Inc.

When it came time to replace the roof on Howard W. Jones Hall, Youngstown State University wanted to closely re-create the original graduated natural slate roof. Photos: Charles F. Evans Company Inc.

Even slate roofs have to be replaced sometime.

Howard W. Jones Hall is one of the oldest buildings on the campus of Youngstown State University in Youngstown, Ohio. The limestone structure with its twin towers is an iconic structure, and when the original slate roof finally deteriorated, the university wanted to keep the stately look of natural slate on the building’s exterior.

Charles F. Evans Company Inc. of Elmira, N.Y., was awarded the Jones Hall restoration job in early 2017 and named 37-year veteran Ken Dennison as the project manager. “We seem to excel in doing difficult projects, including specialty systems of slate, tile, and architectural sheet metal,” Dennison says. “We emphasize quality workmanship and uncompromising customer satisfaction. We also emphasize safety, and currently we are the only roofing contractor to be an approved OSHA VPP mobile Mobile Workforce STAR contractor.”

The university wanted to replicate the existing 6,500-square-foot graduated slate roof with random widths, and slate roofing tiles in the same color and size range were chosen. The scope of work included repairing the existing masonry and installing copper gutters, valleys and flashings.

Going Old School

The first step was removing the old slates, which proved a tough task. “We had to remove them almost one by one,” recalls Dennison.

Copper details were custom fabricated for counterflashing and step flashing.

Copper details were custom fabricated for counterflashing and step flashing. Photos: Charles F. Evans Company Inc.

The existing wood plank deck was in very good shape, and Carlisle Water & Ice Protection self-adhering underlayment was installed at the eaves, valleys and rakes. It was also applied around all of the details. Then two layers of 30-pound felt were tacked into place with plastic-capped nails.

Natural hand-split roofing slate was delivered pre-cut and pre-punched by Evergreen Slate Co., located in upstate New York. The slates were mixed to ensure proper color distribution and arranged in piles for installation on the site. Once the underlayment was in place, the slate was installed just as it might have been a century ago. “We used copper nails,” Dennison notes. “Everything was nailed by hand—two nails per slate.”

The installation called for a 3-inch head lap. “With random slate, you don’t need to put any vertical lines in, because nothing is going to line up vertically,” Dennison explains. “Every side lap has to be at least 3 inches, but there is no set pattern for the widths—we just mix them up. That’s why they use the term ‘random.’”

Handcrafted copper details completed the distinctive, traditional look. Flat-seam copper panels from Revere Copper were installed in the valleys, using clips to allow for expansion and contraction. Copper counterflashing and step flashing were also custom fabricated. “We bend it to fit whatever we might need,” notes Dennison. “We have a talented sheet metal shop at our office where we fabricate the big stuff, but we also cut and shape panels on site.”

Photos: Charles F. Evans Company Inc.

Photos: Charles F. Evans Company Inc.

A detailed safety plan was set up for the building, which was open and active during the entire installation process. Scaffolds with decking were erected at the eaves, and temporary tunnels were engineered to protect pedestrians at the entryways.

The rake edges did not have scaffolding, so a safety perimeter was set up 6 feet from the roof edge. Workers outside the line had use a personal fall arrest system, which was secured to anchors screwed into the rafters. “All of our mechanics are extensively trained, and each year everyone goes through additional training sessions,” Dennison says. “We all know what we’re supposed to do. We have a very stringent plan on project safety.”

Slate itself can pose its own set of safety concerns. “Slate can be heavy and sharp,” Dennison says. “It’s rock. You have to be very careful, but the guys that do it love it. A lot of roofs these days are totally hidden. On a slate project, at the end of the day you can step back, see what you’ve done, and be proud your work.”

Charles F. Evans is just putting the finishing touches on the roof at Jones Hall. “When we’re done with a project and the customer is happy, that’s the best satisfaction you can get,” Dennison says. “When the client is happy and you look back and see a beautiful product that you know you had a hand in—that’s what I like about it. A slate roof is really a work of art that will stand the text of time.”

TEAM

Architect: eS Architecture and Development, Dublin, Ohio, esarchitecture.com
Roofing Contractor: Charles F. Evans Company Inc., Elmira, N.Y., Evans-roofing.com
Slate Supplier: Evergreen Slate Co. Inc., Grandville, N.Y., Evergreenslate.com
Copper Supplier: Revere Copper Products, Rome, N.Y., Reverecopper.com

Project Profiles: Historic Renovation

Maine State House Dome Restoration, Augusta, Maine

Team

COPPERSMITH: The Heritage Co., Waterboro, Maine
GENERAL CONTRACTOR: Consigli Construction Co. Inc., Portland, Maine
ARCHITECT: LEO A DALY, Minneapolis
ENGINEER: Becker Structural Engineers, Portland

To remain proportional with the larger building, a new, higher copper-covered dome was built to replace the original cupola.

To remain proportional with the larger building, a new, higher copper-covered dome was built to replace the original cupola.

Roof Materials

Working 200 feet in the air on elaborate staging, carpenters, coppersmiths, engineers and other construction workers replaced more than 7,000 square feet of copper on the dome. The existing unique, curved copper components were carefully removed and saved to serve as models for the new components.

A full sheet-metal shop, consisting of an 8-foot brake, 52-inch jump shear and benches, was set up onsite at the 63-foot elevation mark, along with five cases of 20-ounce copper (about 12,880 pounds). Each copper component was carefully measured, cut and bent onsite, and then installed.

The compound curving components were made in The Heritage Co.’s “home” shop, using a shrinker/stretcher machine and an English wheel. Then, the copper was handformed over custom-made wood forms. Care was taken to exactly match the size and configuration of the existing components, as well as the seam layouts that were prevalent in the original copper work

Approximately 15 to 18 percent of the copper was waste because of the curved nature of many of the components. The waste was made into copper clip stock for the roof installation or recycled.

COPPER MANUFACTURER: Revere Copper Products Inc.
COPPER SUPPLIER: Beacon Sales Co.

Roof Report

The Maine State House was originally designed by renowned architect Charles Bulfinch in 1832. The dome was added in 1910 as part of a major remodeling and expansion project that ultimately created the building’s current appearance based on designs by G. Henri Desmond.

The original façade was preserved during remodeling, though the length of the building was doubled to 300 feet by extending the north and south wings. To remain proportional with the larger building, a new, higher copper-covered dome was built to replace the original cupola. The new dome rises to a height of 185 feet and is topped by a gold-clad copper statue, called “Lady Wisdom”, designed by W. Clark Noble.

Over time, weather damage and holes caused by hail strikes on the top of the dome caused leaks in the building. The seams between the copper sheets also caused problems for the underlying steel and concrete structure of the dome. The work included the installation of expansion joints, repairs to prevent water infiltration and restoration of the cupola (located between the top of the dome and Lady Wisdom), using a highly durable paint system. Lighting upgrades, copper repairs and the restoration of the gilded Lady Wisdom statue located atop the dome were also part of the project.

The dome’s structural system and framing were analyzed by Becker Structural Engineering one year in advance of dome construction, so Consigli Construction could create a 3-D model for staging to eliminate interior shoring.

Overall, this project restored one of Maine’s most significant historic landmark buildings, returning its signature copper dome and gilded Lady Wisdom sculpture to their original intended conditions.

PHOTO: Consigli Construction Co. Inc.

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