May 15, 2008

DAN O'REILLY

The exterior walls of the circa 1880s Alton Mill required three months of meticulous repointing and stabilization work.

High-tech restoration saves historic Alton Mill from wrecker’s ball

DAN O’REILLY

correspondent

A 1880s industrial stone mill that originally seemed destined for demolition has come roaring back to life. After a 30-month, two-phase, $5-million restoration, the Alton Mill in the scenic village of Alton — just south of Orangeville — is nearing completion.

“We're aiming for a grand opening in late September,” says Jeremy Grant, vice president of planning and development with the Seaton Group, the owner/developer.

Designated as a heritage structure by the Town of Caledon and listed on the federal government’s Canadian Register of Historic Places, the mill consists of the main two-storey mill building, a three-storey water tower, a brick chimney stack, the remains of a number of accessory buildings and an adjacent mill pond and dam which will eventually be rehabilitated as part of the overall development, says Grant.

Built between 1881 and 1913, the mill was the longest running water-powered mill on the upper Credit River system, remaining in operation until 1982.

“It was one of the few surviving mills in the Greater Toronto Area,” says Grant.

His family has owned the 3.4-acre property since the late 1980s, but couldn’t sell the building and had difficulties in finding tenants until they came up with the concept of transforming it into a regional arts centre in partnership with the non-profit Headwaters Arts Festival.

A team of consultants with expertise in heritage restoration is overseeing the project, which is designed to bring the 23,000-square-foot mill up to existing code standards while preserving its original fabric and heritage features

Construction manager is J.D. Strachan Limited of King City. Toronto-based Catherine Nasmith Architect is the architect and Tacoma Engineering of Guelph is the structural consultant.

A small initial renovation of the more useable west section of the mill was completed about two years ago.

A mix of artist studios and galleries now occupies that space and the plan is to continue the theme. It will also include a restaurant overlooking the mill pond, says Grant.

Some of the work required in the more challenging second-phase restoration has included a meticulous three-month re-pointing of the exterior stonewalls, says J.D. Strachan vice-president Don Hutchinson.

Located on the banks of Shaw’s Creek, the Alton Mill originally manufactured wooden products with a turbine powered by water diverted from the creek and into the building through a sluice gate. But over the decades, moisture has seeped into the stone walls and footings.

“We had to stabilize the walls first,” says Hutchinson, explaining that new lintels and windows were also installed at this time to reduce scaffolding costs.

This segment of the project also included reinforcing the walls of a small accessory building, which the developer intends to convert into a riverside courtyard.

As was the practice when the mill was constructed in 1881, the walls consisted of two layers of stone with a hollow space in between.

“We had to pump grout into that area at several different spots.”

“This [reinforcing] was for protection against a one-in-one-hundred year storm,” says Hutchinson, pointing out those protection measures also included installing Nor-am steel windows in the basement, which houses the original turbine.

A major component of Phase 2 was an extensive five-week remediation of the mill’s two large floors by Markham-based Alliance Environmental. “We couldn’t do any interior until that was done.”

After all openings were sealed off with tarps and plastics to prevent airborne particles, dry-ice blasting was used to remove hazardous materials embedded on the walls and in the massive wood columns and support beams.

Dry-ice blasting does minimal damage to stone and wood and is now the preferred technique in heritage restoration.

While appearing structurally sound, a close inspection of the top surfaces revealed a considerable amount of mould and rot had set in. About one-third of the beams were replaced and the rest repaired by Strachan’s own crews.

A new hardwood floor has been installed in those floors which are now being divided into the studio and gallery space.

Some of the remaining work includes pouring the basement for the restaurant and the construction of a masonry shell for an elevator, says Hutchinson.

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