Michigan company restores Union windows to 20th century glory


The tracking list goes something like this: 540 windows, 1,150 individual sashes, 5,218 leaded glass panels and 21,528 individual pieces of glass.

That’s what Full Spectrum Stained Glass, a Colon, Michigan-based restoration company, is working with to fully restore the historic century-old windows of the Michigan Union.

The Michigan Union will reopen in winter 2020. Learn more about the project.

Representatives and staff from the University of Michigan’s University Unions, Student Life, and the student organization Building a Better Michigan recently toured the Full Spectrum facility to watch (and photograph) the process underway.

From start to finish the pictures tell an intricate story of the Union’s past. And fortunately for those who will enjoy the Union when it reopens in winter 2020, those pieces of history will be intact — gleaming like they did at the turn of the 20th century — and will be more energy efficient.

A worker for Full Spectrum Stained Glass works on one of the 540 windows from the Michigan Union that the company is restoring.

The windows are from three different eras — 1919, 1937 and 1956 — so experts needed to modify the restoration of wood sashes, leaded glass panels, hardware and weather-stripping to each era. The process is arduous and exacting

“We made a tracking sheet for each of the 540 windows so at any given time we can tell you at what stage of restoration they are in,” said Full Spectrum co-owner Valerie McCartney.

“The windows will return to the original look and feel of the 1919 windows. That’s why we are restoring them to maintain our history, not universally replacing the windows,” says Amy White, director of the Michigan Union. “Many of the structural renovations to the building will correct previous modifications, some that occluded its natural daylight and blocked its graciousness.

“Every detail of this restoration looks to bring back the natural daylight, while adding to the environmentally friendly efficiency, and restore the look and feel of the Union. That includes each detail right down to the windows.”

Infrared heat is used to remove the window putty by hand. Powertools, which would be much faster, create too much dust and the lack of control could cause additional damage.

Repairing and reassembling the lead panels of the windows takes precision and patience.

Full Spectrum was hired via Walbridge, the renovation construction manager.

The project began in August 2018, when Full Spectrum began a process that took four months to remove, document and assess each window, which were then transported by cargo trailer to be housed in a specially built unit on the company’s property.

To begin the restoration, the windows first enter the Containment Room for the removal of any hazardous lead, dust from putties, and paint on the sashes. That is where the leaded glass panels are separated from the wood sashes.

Next steps in the process include liquid stripping to remove any finishes. Because of the age of the windows, multi-layers of paint needed to be removed.

Many layers of paint are stripped from the windows in order to return them to the original bare wood.

In the Wood Repair Room, “one of the goals is to save as much of the original wood as possible,” McCartney says. “When necessary we used salvaged wood from other Michigan Union windows.”

Completing the process includes refinishing century-old, tarnished hardware to a shine, and then reassembling the stained glass into the window frame with back bedding and glazing to seal the finished product.

While completing sash repairs, co-owner John McCartney says, many remnants of students past were found. “We found names carved into the wood. We saved those pieces and put them back into the restored piece to keep that history alive.”

Hardware, once tarnished to a dull brown, now gleams like new brass.

The inside section of the windows will be storm windows by Peterson Glass Co. with energy-efficient weather stripping. The aluminum framed Thermolite windows will improve energy efficiency as well as reduce noise and provide a security barrier.

Other benefits of the window restoration include better air movement, and easier cleaning and maintenance. The exterior of the windows will be restored to the original color which is similar in tone to the limestone surround. This was discovered through paint samples uncovered on the windows.

“And they will be able to close completely,” McCartney says. “You’ll see a big improvement in efficiency.”

Viewing the process was a sentimental journey for many on the tour.

Susan Pile, director of University Unions, who has been involved since the renovation was just a talked-about idea, was impressed with the meticulous and painstaking work.

“This is such a special project to all of us, a project from our hearts. It meant so much to us viewing this tour, and seeing the work and care put into this aspect of the restoration,” Pile said.



  1. Katie Demidenko
    on March 19, 2019 at 8:05 am

    Thrilled to see the history so carefully preserved. Great work, Full Spectrum Stained Glass!

  2. Katie Vloet
    on March 19, 2019 at 9:10 am

    Working their magic in the Magic Capital of the World!

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