Fort Mackinac Mackinac Island, Michigan

Masonry Construction, Feb, 2003

Fort Mackinac was built in the 1780s by the British during the Revolutionary War, and today stands as one of Michigan's most treasured historic resources and a premier tourist attraction. The ravages of its 220-year life necessitated a comprehensive restoration of the fort to ensure its future. At job's end, 16,250-square feet of the fort's wall were re-pointed and 16,340-cubic feet were replaced or restored.

Traditional methods and materials were used along with concealed modern techniques. For example, a 19th century walkway above the north sally port had long ago been demolished and restoration to its original construction via conventional means would have been structurally unsound. Instead, a system of modern steel anchorages and reinforcing embedded several feet into concrete and fully concealed under a shell was installed to match the original appearance.

A new drainage system was designed to preserve and reuse part of the original stone system, and wood caps were restored on the stonewall tops. Soft mortar mixes compatible with the original construction were used. Inconspicuous expansion joints were placed into rough joints between stones to provide resistance to future wall cracking.

Project Team

Masonry Contractor: Schiffer Masonry, Holt, Mich.

Architect: SmithGroup, Ann Arbor, Mich.

General Contractor: The Christman Co., Lansing, Mich.

Masonry Suppliers: Limestone Specification Stone Products, Alpena, Mich. and Cheboygan Cement Inc., Cheboygan, Mich.