World-class roofing

Mahan Slate Roofing restores Dartmouth College’s Baker Tower


Ranked No. 1 in undergraduate teaching for the past four years by U.S. News & World Report, Dartmouth College is a private research university in Hanover, N.H. A member of the Ivy League, Dartmouth College has been educating students to become leaders since 1769.

The university has about 4,200 undergraduate students in liberal arts programs and 1,900 graduate students in more than 25 advanced degree programs in the arts and sciences and professional schools: Geisel School of Medicine, the fourth-oldest medical school in the U.S.; Thayer School of Engineering, one of the first professional engineering schools in the U.S.; and Tuck School of Business, the world’s first graduate school of management.

At the campus forefront is Baker Tower, home to Baker-Berry Library and the humanities and social sciences departments. Completed in 1928, Baker Tower’s architecture and design was inspired by Philadelphia’s Independence Hall. The building stands 200 feet at the top of its weathervane, making it the tallest occupied building on campus.

While painting building components in 2015, structural issues were noticed, and a subsequent review confirmed deeper preservation work was necessary. In 2016, Dartmouth College’s facilities and operations management prepared for the tower’s first restoration. Mahan Slate Roofing Co. Inc., Agawam, Mass., replaced all the copper roofing, flashing and ornamental components and restored the weathervane.

Getting started

Mahan Slate Roofing began work on Baker Tower in June 2016. There was an extensive amount of work to be done during a five-month period that began with erecting scaffolding on all sides of the 185-foot-high tower. The scaffolding was completely enshrouded with a scrim designed to look like the tower to minimize the visual disturbance of scaffolding. Because of the scrim’s height, design complexity and wind load that would be applied, this step required an engineer’s approval.

The tower’s bells were in great shape and did not need work, so they remained in place during restoration.

Tower copper

After scaffolding was in place, Mahan Slate Roofing workers removed all the existing copper from the tower and documented seam patterns.

“All the architectural copper was removed from the bell tower and brought back to Mahan Slate Roofing’s offsite sheet metal shop where it was replicated,” says John Mahan, vice president of Mahan Slate Roofing. “Because of the building’s historical nature, every copper profile had to be matched exactly.”

The newly restored finials and fabricated spun-copper balustrade, drip edge and railings then were transported back to the project site and reinstalled on the tower. Before the railings were hoisted to the roof, workers painted them white to match the original design.

New standing-seam and batten-seam panels were installed over the wood roof deck along with associated flashing. At the tower’s second lantern, Mahan Slate Roofing craftsmen installed flat-seam copper and moldings and clad the shadow panels in copper. At the finial on level five, workers clad the post and railing in copper, and copper flashing was installed at the clock.

Weathervane

When the tower originally was being built, Dartmouth College held a contest to design the weathervane. The prize was a Dunhill pipe brought to Hanover from Montreal. Architect Stanley Orcutt’s design, “Wheelock and an Indian under the Pine,” was selected as the winner.

“Because of the weathervane’s historical value, Dartmouth College was adamant about repairing it versus replacing it,” Mahan says.

Workers removed the weathervane from the roof via a crane and transported it to the off-site shop where the existing copper, armature, directional structure and letters were removed. Using original drawings, craftsmen then restored the weathervane and refurbished all details, including the weathervane’s connection. The 3-foot-tall copper ball also was restored to original condition, and new directional letters and an assembly were fabricated and installed. The new weathervane is nearly 9 feet long by 7 feet tall and weighs about 600 pounds.

Louvers

From the belfry level, workers removed the copper-clad wood louvers and removed the original copper. The original wood louvers then were clad in new copper, and a new bird screen with aluminum frame also was installed.

Tower levels 1-3

The Tower Room is located on the third floor and is considered one of the most beautiful rooms on campus. The room houses a collection of classic novels, popular fiction books and mysteries, as well as books about sports, art and travel.

Because of annual historical events held at the library, the only time construction was allowed was between June and November. To accommodate interior renovations that included new cork flooring, electrical upgrades and USB ports in every outlet, and new lighting and paint, the Tower Room was closed June 20-Sept. 23, 2016, but the rest of Baker Tower’s third floor remained open for the nearly 3,000 visitors who tour the tower annually. While the tower remained occupied, Mahan Slate Roofing workers successfully removed and replaced the standing-seam and batten-seam copper roof systems and flashings.

“From crane schedules to materials being ordered and brought to the site, for the amount of work that needed to be completed it was an extremely tight timeframe,” says Robert Fulmer, the project’s initial design consultant and principal of Fulmer Associates LLC, North Conway, N.H. “Everyone involved did an outstanding job with coordination and communication.”

From the library’s roof area, workers removed the existing copper and replaced it with new standing-seam and batten-seam red copper. They also removed and replaced the copper flashings.

From the tower dormers, Mahan Slate Roofing workers removed and replaced all the standing-seam copper roofing, flashings and trim; removed and replaced copper cladding; and installed new copper trim and casing and new copper sills at dormer windows.

Membrane roofing

In addition to the copper roof systems, workers removed and disposed the existing gravel ballasted roof system from the low-slope sections and replaced it with a Sarnafil® PVC roof system that included two layers of 2-inch-thick rigid insulation and a protection board.

With honors

In November 2016, Mahan Slate Roofing completed its work on Baker Tower on schedule. In addition to roofing work, a new digital control system for the bells and clock was installed along with new energy-efficient exterior lighting to highlight the building’s restored architectural details.

Thanks to Mahan Slate Roofing’s workers, the architectural significance of the facility was retained while components were updated, successfully preserving the tower’s original structure to ensure another 100 years as a prominent feature of Dartmouth College’s landscape.

“Mahan Slate Roofing workers fabricated unique and intricate copper work, endured an extremely tight schedule, coordinated with multiple subcontractors, and completed the project on time and on budget while ensuring normal occupancy and day-to-day activities of the library,” Fulmer says. “Their quality and creativity in the work they perform goes above and beyond what is expected.”

For demonstrating exceptional workmanship on Dartmouth College’s Baker Tower, Mahan Slate Roofing received a 2019 Gold Circle Award in the Outstanding Workmanship category from the Roofing Alliance and a 2019 North American Copper in Architecture Award from the Copper Development Association Inc.

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



Interesting facts about Baker Tower’s bells

The tower has 16 bells ranging in sizes from 200 to 5,300 pounds each. The bells were rung manually in 1928. In 1929, an automated system similar to a player piano was installed. Holes were punched into a roll of paper, and the locations of the holes triggered the bell mechanism. In 1979 when the original paper rolls started to wear out, two students created a computerized bell system. The bells now run via wireless access, and an iMac computer in the tower runs custom-designed software written by a graduate student in electro-acoustic music programs.

The bells ring the time on the hour and half hour, and songs are played three times per day—the Alma Mater at 6 p.m. and varying pieces during intervals between classes. Songs can be requested by campus goers with current favorites being “Hey Jude,” “You are my Sunshine,” “Hi Ho Hi Ho” and “Feeling Groovy.”



Project name: Dartmouth College Baker Tower Renovations
Project location: Hanover, N.H.
Project duration: June-November 2016
Roof system types: Copper and PVC
Roofing contractor: Mahan Slate Roofing Co. Inc., Agawam, Mass.
Roofing manufacturers: Revere Copper Products, Rome, N.Y.; Sika® Sarnafil,® Canton, Mass.

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