The experience also helped IMI, which is a strategic alliance of the International Union of Bricklayers and Allied Craftworkers and union contractors, enhance its specialty training courses in classic techniques.
Historians and substrates
One of the best examples of Georgian architecture in America, the Brice House was constructed between 1767 and 1773. Its illustrious neighbors include the U.S. Naval Academy, St. John's College and the residences of all four Maryland signers of the Declaration of Independence. Original owner James Brice once presided as mayor of the city, which itself earned National Historic Landmark status in 1966.
Brice's former home is a showcase for plaster craftsmanship, as well as brick and stone. The interior features outstanding plaster walls and cornices, while the exterior features a stone foundation with 326,000 bricks laid in structural header bonds typical of that period.
Although remodeled for many different uses over the years, it was never faithfully restored until IMI moved its headquarters there. Working closely with area historians eager to preserve the house's historical significance, IMI chose to follow historical plaster practices and traditions, including tools and materials, such as lime mortar.
The restoration was designed by Stanley Tigerman, FAIA, principal of the Chicago firm of Tigerman/McCurry Architects, working with general contractor Carlson Construction. IMI Plaster Instructor John Totten oversaw the 10-week restoration and provided hands-on expertise.
"The collaborative effort between the designer, the general contractor and highly skilled BAC craftworkers to overcome the many unique challenges of a structure more than 200 years old was truly remarkable," says IMI Director of Strategic Programs Greg Stinner, a former Army Corps of Engineers director. "It was one of the most challenging and rewarding projects in my career."
The restoration process started with repairs to the substrates. Brick walls were exposed on the interior, which meant demolition of the old plaster and wood lath when necessary. Floors were taken up and floor joist bearings were repaired to meet the structural requirements.
On the ground level, brick floors were reinstalled per the original configuration. Below grade, repairs to the foundation were made.
Interior and exterior masonry walls were repaired as needed. Areas with structural deterioration were restored with brick units closely matching the characteristics of the original units from the 1700s.
Mortar was researched and batched to closely match the original characteristics of the 1700s lime mortar. Wood lath, of similar configuration to the original, was installed in large areas where it was useless to attempt repairs.
The future of the pastMore research was needed to match the lime plaster, which led to development of a plaster formula using ox hair as a binder.
The plaster was then installed using the original "hurled" technique and trowel-finished with a lime wash final coat. The wash of 60-percent lime and 40-percent water had a small amount of pure linseed oil to take the chalkiness off walls and ceilings. On the wood lath, base and finished coats were applied and topped with a lime wash, as well.
The traditional materials left IMI at the mercy of the weather, which upped the challenge by bringing rain on 56 of the 60 days. The ambient moisture called for extraordinary measures. Equally challenging were material delivery, production scheduling and coordination. Nonetheless, by early June of 2003, some 20,000 square feet of wall were restored.
Now part of a ground floor office, the original kitchen wall was left exposed and covered with glass to showcase the elaborate restoration process. One of the last unimproved walls from the 18th century, it retains the outline of a hutch, having escaped change by being covered with a false wall.
All plasterers who worked on the project were trained by IMI, which offers plaster training programs at all levels of the profession, complementing BAC plaster training efforts at the local level.
At the entry-level, IMI continuously runs a 12-week pre-job course at the BAC/IMI National Training Center in Maryland, as well as regional centers throughout the country. The course covers traditional three-coat plaster with rock and metal lathe, traditional three-coat stucco, Venetian plaster, ornamental plaster, exterior insulation and finish systems, and AAC coatings. For BAC journeymen, IMI offers training in specialized products like AAC coatings, as well as the classics, like Venetian plaster and Marmorino.
The Brice House restoration further underscored IMI's commitment to historic restoration this summer, when it served as the backdrop for the inaugural session of a national conference series on historic masonry.
IMI National Director of Apprenticeship and Training Steve Martini notes that, over time, additional repairs and restorations will be scheduled for Brice House. Those will be carefully recorded and saved as potential teaching tools for BAC members in the field of restoration and reuse of historical structures.
"Even our seasoned plasterers learned a lot on this sensitive project," says Martini. "We all learned practical techniques and processes that we can share with other BAC members. We also have a beautifully restored historic treasure that is an outstanding example of our early masonry heritage in this country."
The center block of the five-part house is now used to host educational exhibits for BAC and IMI. The East Wing houses administrative offices.
The West Wing serves as a teleconference center and the home of the George Spencer Masonry Library. The industry's only masonry library, it features a comprehensive collection of masonry resources and masonry bibliography. It is used for seminars and industry events, including meetings of the Masonry Industry Council and US/ICOMOS.
The library was made possible, says IMI Co-Chair and BAC President John J. Flynn, by contributions from both BAC locals and union contractors, along with 700 volumes donated by BAC.
His management counterpart, Eugene George, president of the International Council of Employers and GA Masonry, urges interested parties to visit.
"The collection," he says, "is a valuable resource to everyone involved in masonry."