preserving the old for new generations

Historic stone structures are precious resources that provide us with a tangible link to our past. Their unique designs and solid construction often reflect the best work of accomplished stone masons and stone carvers from their respective time periods. We cannot afford to lose the materials, ideas, skills and knowledge of our past.

Though natural stone is among the most durable materials used for construction, it ages and weathers with time, necessitating repair or replacement. Finding suitable stone for the repair of historic structures can be difficult, since few of the original quarries remain in use. Often, significant detective work is required for stone identification, sourcing and matching.

If the exact stone is no longer available, other options can be considered. Hundreds of quarries around the United States produce a wide variety of building stone and are potential sources. Quarriers and fabricators of stone, including several Building Stone Institute members, have worked with architects and contractors to successfully match or recycle stone on a variety of restorations. Here, Building Stone Magazine examines several of these projects.

Toronto's Old City Hall
What Toronto residents refer to as "Old City Hall" is located on Queen Street at the top of the original Bay Street. It was begun in 1889 but not opened until 10 years later on Sept. 18, 1899. In one structure, these municipal buildings combined City Hall, in the east portion, and the courthouse in the west. This building is constructed mostly of Credit Valley sandstone, a grey stone with a sandpaper-like texture quarried near Toronto. Massive, round-arched, and richly carved, it is in the Romanesque Revival style, which was popular in cities throughout North America at the time. The interior includes a large stained glass window by Robert McCausland. In 1965, the Municipality of Metropolitan Toronto acquired the building when the city offices moved to a new City Hall on the adjacent Civic Square.

"Owen Sound Ledgerock has been working on this for about 10 years, replacing at least one part of every architectural element on the building over four phases as we work around the building," explains Andrew Negus, "sills, coursing, banding, cornices, carvings, steps, arches, columns, etc." They have been working mostly with The Ventin Group Architects and Clifford Restoration of Toronto. Most of the more decrepit areas of the stone masonry construction have been cleaned, replaced or rehabilitated.

Most recently they've completed phase four, which involved about $1 million in custom sandstone work. "It's a similar circumstance to the Parliament Building," explains Negus. "We've been completing all kind of product, including customized carved items to match existing carvings on the building, arches and columns on the 450-foot clock tower on the front portion of the building — many of the items right at the top." He notes that the clock tower was actually completely wrapped in scaffolding over 400 feet high and equipped with a special high mass-load elevator for shipping pieces from the ground to the top. The tower was closed off allowing masons to work both inside and outside of the building.

Negus says that some of the stones they replaced weigh as much as 13,500 pounds — mostly mammoth sills and headers. "It's a masonry construction building — typical of construction in its day," he explains. "That's what supplies the major support, as opposed to today where your primary support is concrete and steel. Some of these sills are 40 inches deep."

New York State Capitol Building, Albany
Unlike many state capitol buildings, which are inspired by Classical architecture, the New York State Capitol building was inspired by the design of the Hotel de Ville in Paris. The structure was designed and constructed over a 32-year period and finally completed in 1899. At that time, it was admired by many as one of the most beautiful buildings in America and ridiculed by some as an expensive boondoggle. But no one could deny that it was unique.

It was built by hand of solid masonry — in places its walls are four or five feet thick. When construction began, electric lighting did not exist and mechanical heating and ventilating were primitive at best. Before it was completed, improvements had been made in building technology. Electricity was used to light the Capitol and advances in heating were incorporated into the structure.

Today, the Capitol building is undergoing an extensive renovation to return spaces to their appearance a century ago. At the same time, improvements are being made to ensure that the building will meet the needs of New York State government in the future. "We've been involved in almost all the work in some way," says George Mallette, vice president of Adam Ross Cut Stone, Albany, N.Y. "It's an ongoing project with numerous phases and proposals that extend 15 to 20 years into the future."

Originally, three teams of architects worked on the Capitol building construction, led by Thomas Fuller from 1867-75, Leopold Eidlitz and Henry Hobson Richardson from 1875-83, and Isaac G. Perry from 1883-99. The various architects' influences likely account for the wide variety of stone used in and outside the building. Finding the right match for each can be a challenge. "On the outside of the Capitol, the only stone that will match is Concord Gray Swenson granite, but on the inside, there's stone from almost anywhere you can imagine," Mallette says.

Adam Ross Cut Stone is presently doing a project that involves importing stone from Nova Scotia — and that's from a quarry which is currently closed. "As for this closed quarry, there was an operating quarry in the vicinity of the closed quarry," says Mallette. "Often the owner of the operational quarry will purchase miscellaneous, previously-cut blocks from the current owner of the land." Normally, after a quarry is closed, it is nearly impossible to re-open it because of residential and commercial development surrounding the quarry. It is not a typical practice to obtain stone from a closed quarry, so the search begins for comparable stone from other sources.

However, some searches connected with this renovation are easier than others. Over the years, they've had the foresight to save leftover stone from previous work on site. "A lot of times, I'm able to go into the basement archives and pull out a good portion of what I need," he says. "We can often recut and reuse it."

Sometimes, Adam Ross Cut Stone is asked to rebuild areas that have been heavily modified or even removed. "For example, if I'm working on a third-floor restoration, they'll refer me back to the first floor where everything is still intact and ask me to match it," Mallette explains. "I'll make plaster of Paris molds of carvings — everything has to duplicate what's already there."

Work of this scale is ongoing and takes a long time. "The building is just one large mass of hand carved work," says Mallette. "The job I'm working on now started four years ago and I still haven't cut a piece of stone for it yet. There's a lot of prep work and searching for the best matching stone."

Fort Ticonderoga, N.Y.
Built by the French in 1755, Fort Ticonderoga, N.Y., was the gateway to Canada and the site of a decisive battle during the French and Indian War. On May 10, 1775, at the start of the Revolutionary War, Ethan Allen, an American Revolutionary soldier, led his Green Mountain Boys in an attack to overtake the fort. These soldiers from Vermont seized Fort Ticonderoga and all of its valuable artillery stores without a struggle.

In 1820, William Ferris Pell bought the ruins of Fort Ticonderoga and the Garrison Grounds to preserve them. Pell built the Pavilion, a hotel to cater to the growing tourist trade in the area. His grandson, Stephen H. G. Pell, officially began the fort's official restoration in 1908. Since then, several rounds of restorative efforts have been made. "We've addressed a substantial amount of work in the last 10 years — officially in excess of $4 million worth," says Lyle St. Jean, superintendent of buildings and grounds. "Currently, we're building a new education center within the fort itself. We're careful not to alter the original footprint or the style of work done here."

According to St. Jean, they strive for 100-percent authenticity with the fort. They reuse stone where possible and fill the gap by carefully matching new stone from local quarries. Champlain Stone of Warrensburg, N.Y., supplied nearly 90 custom pieces of Great Meadow limestone from its nearby quarry in 2006. "Most of what we reuse is on the fade — as an average our walls are 20 feet high, the face of any single bastion is an average of 80 feet long, making 1,600 square feet on any given face on a bastion," St. Jean says. The gun decks are all clad with South Bay quartzite from Champlain Stone, which provided more than 200 tons of flagging from 1999 to 2006.

To date, restorers have refurbished approximately 40 percent of the fort. Unfortunately, a substantial amount of the current restoration includes correcting mistakes from previous work. "Most of the restoration done between 1910 and 1940 did not follow good, solid practices," says St. Jean. "Those walls have failed, and we still have 50 to 60 percent of that work to catch up with over the next 10 to 12 years to comply with the recent State Historical Preservation Office standards." During the original restoration, they backfilled the walls with clay as an inexpensive fix. Over time, poor drainage and freeze-thaw cycles pushed the walls over.

Restoring the walls starts with removing any earth or clay behind them. "We then rebuild with concrete, structural steel, precast or cast-in-place concrete and clad the face," St. Jean says. "So all we're looking at when we get done is the face itself. In other words, we take a three-foot wall down and put back a 16-inch veneer, so we actually gain stone on most of our projects." The wall appearance is authentic and more structurally sound than the original 1755 structure.

Wacker Drive, Chicago
Wacker Drive, a historic, bi-level roadway built in the 1920s, runs alongside the Chicago River and is home to many of the city's notable landmarks. But after suffering decades of Chicago's harsh weather, the original road was falling apart. Despite repairs in the 1970s, the road continued to show failures. In 2001, Walsh Construction began the monumental task of reconstruction.

The purpose of the reconstruction was to replace the existing structure and to widen the street to accommodate the demands of today's traffic in the Windy City. The challenge was to upgrade the structure while preserving its original characteristics. "The goal of any infrastructure project is to respect the context and to recognize its value as public architecture," said Charlie Friedlander, senior architect, DLK Inc. of Chicago. "It's not only individually iconic, it's part of the city fabric."

Before the road construction began, collaborative teams of architects, preservation specialists and engineers on the project decided how much of the existing natural stone could be reused form the cladding, base, staircase, and other defining stone features. These pieces were cataloged, disassembled, stored and repaired for reinstallation. Pieces that were too worn would be replaced with matching units.

Matching new stone to the old was the next challenge. "Matching a 100-year-old weathering condition with new stone is problematic," says Bill Grosche of Johnson Lasky Architects, Chicago, Illinois. "You have to decide to what extent you want the new stone to match the old after the old stone has been fully cleaned, so as to avoid a patchy appearance. Matching the stones was complicated by the variable surface appearance, due not only to irregular weathering and staining, but by the past application of preservative surface treatments."

Restoration teams worked with Cold Spring Granite of Cold Spring, Minn., on stone selection and Cornelian granite became the material of choice. After some extensive research, site visits and analysis of the original materials, Cold Spring Granite found three finish "recipes" that had a good visual match and characteristics comparable to the original. The restored and new stone appear to blend seamlessly.

The renovated Wacker Drive opened in November 2002 after $200 million of work was finally completed. Using a combination of modern, high-performance concrete and some old-fashioned stone renovation, it is expected to hold up for at least the next 100 years.

Queen's Park Parliament Buildings
Queen's Park, which opened in Ontario, Canada, in 1860, was long considered as a location for new parliament buildings. During 1879 and 1880, the Ontario Legislature and city council authorized construction, awarding the commission to architect Richard Waite of Buffalo, N.Y. The main block of the massive Romanesque Revival structure, with its towering legislative chamber, was completed in 1892. On April 4, 1893, the first legislative session in Queen's Park was opened under the direction of Premier Sir Oliver Mowat.

Owen Sound Ledgerock Ltd. has been involved with the exterior restoration of this historic structure since 1996. "During the very first phase of our work, we actually trucked our equipment down to the Medina sandstone quarry and sawed a number of blocks out for that restoration ourselves — which is a little unorthodox," says Andrew Negus, director of custom sales and design. "The quarry itself had limited capabilities at the time, so it's likely we got the contract because we were able to provide the service. The quarry was not providing dimensional stone at the time and extraction was mostly for aggregate. They had no sawing equipment — they used only drilling/plug and feather technique."

Restoring this structure has required several other varieties of stone as well — some harder to find than others. Owen Sound Ledgerock has imported St. Bees sandstone from Cumbria, England and Medina from Rochester, N.Y. — both of which are fine grained and red in color — and Credit Valley sandstone from the Toronto area. "Most recently we've been doing the Whitney Block phases of that project, using stone from a defunct quarry near Niagara Falls — Queenston limestone," Negus says. "When that quarry product ran out, we started using Victor Oolitic Indiana limestone, which the consultants decided was the closest match."

from:stone365.com