Focus On: Advanced Masonry Restoration
By Denise Woods, AGC of Minnesota Director – Communications and Events
There are opportunities in this industry for companies of all sizes and disciplines. Some turn concrete and steel into skyscrapers. Others create the mosaic that is our transportation system. Still others that specialize in taking down the old to make room for the new. And those whose focus is the preservation of the old. Advanced Masonry Restoration (AMR) has found its niche as a preservationist.
In the 1980s, Tom Kromroy was running his own asbestos removal business. Tim Miller, whose background was in masonry, began working for Tom in 1989. Tom sold the asbestos company in the late 1990s and he and Tim went into partnership. They purchased the assets of a masonry business owned by Tim’s brother-in-law. Once they completed that company’s existing projects, they went to work building the new company. In just a few years, AMR has created a portfolio that includes several high profile, award-winning projects.
Repairing and restoring the facades of older buildings, some dating back to the late 19th century, can present many unique challenges. Is the building on the Minnesota or Federal Register of Historic Places? What were the original materials used on the building? Are those or similar materials still available? Will any special glazes or caulking be needed? How closely can the original brick, stone, marble, or terra cotta be matched to create a seamless blend of new and existing? Workers at AMR are true craftsmen, with an impressive number of years of experience among them. There isn’t a material, style of work, or potential problem at least one of them hasn’t encountered before.
While many AMR projects have had unusual aspects, two in particular stand out. The Midtown Exchange in south Minneapolis was an extraordinary undertaking. Due not so much to intricacies in the work required but because of the building’s exceptional size. And in order to stay on schedule and meet the project’s spring 2006 deadline. The project required working 10 hour days, 7 days a week – outside – through the winter. The size and shape of the Coughlin Campanile, or bell tower, at South Dakota State University, Brookings, presented a different kind of challenge. At 167 feet straight up, with a fairly smooth surface and no window openings or ledges, setting scaffolding and lifts and ensuring worker safety required extensive pre-planning.
Hard-working, reliable employees are the foundation of any successful company and AMR is no exception. The current office staff of eight includes Tim’s brothers, Tom and Bob, and several of the craftsmen can trace their connection to the Miller family back to employment with the Miller brothers’ father more than 20 years ago. Because AMR’s commissions are primarily exterior projects, the number of jobsite workers peaks between April 1 and November 30, during the best weather for outdoor working conditions.
On average, 45 workers are employed by AMR. Because the type of work performed by AMR requires not only specific skills and a great deal of patience but also an artistic sense, finding the next generation of workers, who have a desire to learn from the current workers, is something Tom and Tim have already seriously considered. They are involved in an apprenticeship program through Bricklayers & Allied Craftworkers Local #1 to help find and train their future workforce.
The safety of all AMR workers, whether working on scaffolding halfway up the front of a building or tuckpointing near a foundation, is always at the forefront of job planning. Tom and Tim are proud of the fact that there has not been a work-related injury to an AMR employee in more than two years.
The AMR team has already been the recipient of several well-deserved awards from industry associations, architectural institutes, and preservation societies. Current projects include Northrop Auditorium at the University of Minnesota. AMR workers will be involved in the planned restructuring of the Foshay Tower in downtown Minneapolis. The 150th anniversary of Minnesota’s statehood is approaching, and there are many significant historic buildings around the state still in existence. Many buildings need restoration. There won’t be a lack of projects for the skilled craftsmen at AMR any time soon.
By Brian Johnson, Finance & Commerce Magazine Construction Writer
An exterior restoration that will bring Northrop Memorial Auditorium closer to its original appearance is nearing completion, one brick at a time.
For more than a year, crews from Advanced Masonry Restoration have been cleaning stone, tuckpointing, caulking, waterproofing and restoring the exterior of the 78-year-old building, one of the most recognizable structures on the University of Minnesota campus.
It’s part of a $21 million effort to stabilize Northrop and improve safety. J.E. Dunn is the general contractor for the overall project, which addresses the roof, emergency interior lighting, water damage and other issues.
The exterior improvements should be done by the end of October, according to Tim Miller of St. Paul-based Advanced Masonry Restoration.
Exterior touchups are nothing new to the firm, but the Northrop project is unusually complex because of the historic nature of the building and the difficulty in finding matches for the rare brick, stone and terra cotta.
“That was an onerous process,” Miller said. “It took, I bet, six weeks trying to get the right color for the mortar and stone.”
Thousands of exterior bricks had to be replaced, Miller said. Since exact matches are no longer available, workers had to mine bricks from the back sides of the parapets and reinstall them on the front.
Advanced Masonry is limited in what it can do to the exterior. Chemicals and pressures that might be fine for an ordinary building are unacceptable because of the sensitive nature of the building.
The cleaning part required a low-pressure wash with water and detergent — enough to properly clean the exterior without taking the detail out of the carvings or otherwise harming the stone and brick.
“You have to be careful not to damage anything,” Miller said. “The limestone can be soft in spots.”
At the same time, workers faced the task of removing nearly 80 years of dirt and grime, in addition to making sure the building is watertight and dealing with loose bricks and other potential safety issues.
New doors and railings, hazardous material abatement, safety upgrades, and miscellaneous improvements are also included in what’s supposed to be an “80-year fix” for the building, according to Miller.
The building’s unusual size and shape made it difficult for workers to hoist materials from the ground. Elevator service wasn’t available, so a pulley system did the trick, according to Miller.
Miller noted that the project is a design-build effort — a rarity in exterior renovations. Construction begins before final design is completed, meaning contractors have to be flexible enough to accommodate unexpected changes.
Because of those complexities, the work has taken about twice as long as a more traditional exterior project.
The building — which hosts concerts, graduation ceremonies, and other events — has remained open during the entire construction schedule, so the crews have had to work around the normal hustle and bustle associated with a university campus.
Last week, for example, a freshman orientation was booked for Northrop Auditorium and the project team had to hastily remove scaffolding from the front of the building in advance of the event.
“You learn to roll with the punches,” Miller said.
When the exterior work wraps up this fall, Northrop will more closely resemble the building that first opened in 1929. The changes may not be striking to an outsider, but those who walk in and out of university buildings every day will know the difference.
“The people who are considered part of the ‘U,’ they will know how good it looks,” Miller said.
Steven Rosenstone, dean of the College of Liberal Arts, said some of the exterior improvements won’t stand out visually because “some of the stuff is what you do to keep buildings from falling down.”
The project ensures that the envelope is “completely protected and there are no further leakages and water damage,” added Rosenstone, who chaired the Northrop improvement committee for the university.
At the same time, passersby will “see details you never saw before because of the work that’s being done,” Rosenstone said. “It’s going to look cleaner and sharper than ever before.”
Pillsbury A-Mill Artists’ Lofts Get a Lift
By Tim Miller
The Pillsbury A-Mill was erected in 1881 in Minneapolis, Minn., and operated two of the most powerful direct-drive waterwheels ever built. It was listed on the National Register of Historic places in 1966 – one of the earliest registrations. Coincidentally, buildings built in 1966 are now eligible for listing on the National Register.
The original purpose of the building, which was owned by the familiar Pillsbury family, was to mill flour. Purchased in 2012 by Dominium Management, the goal was to take the dilapidated building and turn it into affordable artists’ lofts, preserving the exterior as it originally appeared. The complete exterior restoration of the building was central to the overall project and to the historic Mill District of Minneapolis.
Advanced Masonry Restoration, Inc. (AMR) was called in to perform all phases of restoration, from masonry to stone and concrete repair.
Parapet Repair and Removal
The existing stone parapet was a “Platteville limestone” of multi- width construction. The parapet was removed from the top down six feet, and the attic area above. A new core-filled interior block wall was installed, and the exterior finish was a “Lannon Pewter Gray limestone,” quarried near Green Bay, Wis. It was chosen for its close match to the existing remaining Platteville limestone. More than 1,500 square feet of new stone was installed on top of the building, along with the block, mortar and rebar to install a new wall.
Stone Sill Replacement
All of the window sills were removed and replaced with the same Lannon Pewter Gray limestone. In addition, during the period of significance, a concrete wash was installed, and AMR replicated the concrete sills in both design and material.
Each and every stone mortar joint was removed and
replaced on the exterior. The majority of the stone joints were finished with a struck/doweled joint that was slightly concave and matched the original interior mortar color. When it came to the Main Street elevation below the revitalized canopy, the joints were repainted with a raised joint using a tool fabricated by AMR to match historic photos and records. This was done to show that, at one time, the entire building may have had this raised joint on it.
As an interesting side note, the Main Street elevation has a bow in it extending out about 6:-8 inches across the elevation. Within a few years after the building was built, whalers were installed to keep the building from moving. On the opposite side, concrete bracing was poured to stabilize the building. The concrete was restored by AMR and is visible on the east elevation.
Rebuilding of Windows and Stone Replacement
Several windows were rebuilt to original specifications to correct modifications that were made over the years. AMR successfully restored several arched windows to their original condition.
Cleaning of the building was completed under the auspices of the Secretary of the Interior Standards, and no acid-containing or other harsh chemical agents were used in the cleaning process.
The project was completed in 2015, and each added year will enhance the restoration to replicate the original condition.