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.”