Nearly 90 years after it was built, the University of Michigan's historic William L. Clements Library is finally about to enter the 21st century.

The university has dedicated $10 million of its money and $6.8 million in donations to a two-year renovation project of the building on U-M’s central campus tucked behind the Harlan Hatcher Graduate Library and next to the Shapiro Undergraduate Library.

The Clements Library, built in 1923 and designed by Albert Kahn, houses a large collection of books and documents on American history prior to 1900.

Though much of the renovation won’t be visible from outside, researchers will have a much different experience inside: The historic, rarely used great room will be converted into a reading room.

In its present arrangement, researchers review documents in a small room in the library’s basement, which is lined with card catalogs and curator’s offices.

About 15 people can fit around the small tables in the room -- but they don’t have much room to spread out their research materials, said Ann Rock, development director for the library.

With wood paneling, tall windows and chandeliers, the great room will be able to accommodate many more researchers on larger tables that will be equipped with new lamps. Lining the room are built-in bookshelves that house part of the collections.

The great room is used fewer than five days per month for events like lectures, special exhibits and receptions, Rock said.

Moving the reading room from the basement to the great room is a part of a shifting attitude by Clements Library administrators to bring in more people to the building.

Rock called it a “changing culture” at the library: “We’re really opening the doors to show people what we have,” she said.

Among those documents are the first letter written by Christopher Columbus, and all of George Washington’s medical records.

Rock attributed the change to the library’s director, J. Kevin Graffagnino, who has held that position for about 4.5 years.

The biggest physical expansion of space for the library will be a 3,000-square-foot basement addition that will add space for mechanical equipment. A part of the expansion will also be used to house shelves of books - and will give the library room to grow its collections.

The underground addition will be barely visible from the outside, as the area above the new addition will likely be covered with landscaping.

Electrical wiring will be upgraded, as will the wireless internet capabilities in the building to handle more computers.

The entire building will also be equipped with a fire suppression system and security cameras will be installed, Rock said. Heating and cooling systems will also be replaced to give curators more control over the climate inside the building to protect the collections of old books.

The library closed to the public in July. During the two years that the library will be closed for the renovations, most of the collection will be available for review at a facility at 1580 Ellsworth Road in Ann Arbor.

Staff will begin moving the collections in August, and the Ellsworth Road facility will open to researchers Oct. 1.

Amy Biolchini covers Washtenaw County, health and environmental issues for AnnArbor.com. Reach her at (734) 623-2552, amybiolchini@annarbor.com or on Twitter.