An Albert Kahn-designed building owned by Wayne County at 640 Temple St. in Detroit is the target of a $20 million-plus redevelopment plan that includes Gretchen Valade, whose grandfather Hamilton Carhartt founded the eponymous Dearborn-based workwear brand Carhartt Inc. in 1889.

The building, which was built in the 1920s, is expected to undergo a 24- to 30-month redevelopment after the Wayne County Commission considers approving the agreements in the next three months, according to sources familiar with the plan.

Among the plans: more than 100 apartments ranging from 850 to 2,000 square feet, plus about 10,000 square feet of retail space in new construction to the west of the 190,000-square-foot building, sources said.

Sources said Christos Moisides, executive member of Detroit-based 400 Monroe Associates LLC, and David Sutherland, partner with the Wakefield, Sutherland & Lubera PLC law firm in Grosse Pointe Farms, are the other members of the development group.

Valade is a prominent business figure and philanthropist from Grosse Pointe Farms and this year was named one of Crain's 100 Most Influential Women. Among a variety of other philanthropic contributions and awards, she received the Max M. Fisher award for outstanding philanthropist in 2007 and donated $15 million to the Detroit Jazz Festival endowment.

Valade also recently purchased a block on Kercheval Avenue in Grosse Pointe Farms' Hill neighborhood. She owns the buildings that house her businesses on the next block of The Hill. Those include the Dirty Dog Jazz Cafe, Morning Glory Coffee & Pastries and Capricious, a shoe and accessory store.

In 2015, she donated $7.5 million to Wayne State University to create the Gretchen Valade Jazz Center, which will operate out of the Hilberry Theatre.

The main developer on the 640 Temple project is expected to be Byzantine Holdings LLC, which is registered to Moisides. Byzantine Holdings is also a member of the anticipated building ownership group, Temple Group Holdings LLC, which is owned by Moisides, Sutherland and Valade, sources said.

The 640 Temple building had been targeted by Okemos-based PK Development Group LLC for redevelopment this summer, but those plans fell through. It was slated for 150 to 200 apartments.

Just a few blocks northwest of the Little Caesars Arena under construction for the Detroit Red Wings, the building has been targeted for sale recently in light of the county's financial woes.

A report last year by O'Keefe LLC said the county spends more than $8 million per year in lease costs, which could be reduced by moves including office consolidations and ending unnecessary leases. It also said the county needs to sell real estate for which it no longer has a practical or justifiable use.

It suggests not only selling the buildings at 640 Temple and 511 Woodward Ave. and a parking garage on First Street, but also the Guardian Building and then leasing space back from the new owner.

Moisides' 400 Monroe was tapped last year to help Wayne County squeeze more revenue out of its real estate holdings.

In October, the Michigan Department of Treasury released the county from its consent agreement, 14 months after the county requested the consent agreement as it was grappling with a $52 million structural deficit and an $82 million accumulated deficit.