Stray Dogs’ milkshakes could be topped with candied apple or doughnut holes.

Months after initiating talks to sell their building at 78 W. River Road and hours after the buyers signed the paperwork, the owners of Stray Dogs announced just after their lunch rush Tuesday that they were closing within hours.

The restaurant, which replaced Zona 78 two years ago, was to close at the end of business — around 10 p.m. — Tuesday night, owner Tom Firth said.

“It’s definitely bittersweet,” said Firth, the managing partner of Hacienda del Sol and a co-owner of Zona 78 on East Tanque Verde Road. “The business has been great. It’s just a lifestyle decision.”

Firth and his partners have owned the building on West River Road since 2003, when they opened the wood-fired pizzeria Zona 78. And for the past year or more, the folks who finally bought the building had been courting the Stray Dogs team to sell, something they had resisted, Firth said, until late last fall.

In November, the two parties had reached a deal and gone into escrow with the stipulation that once the deal was signed, Stray Dogs had until the end of that business day to stop operations. The sale is expected to close Wednesday, he said.

That gave Firth and his partners mere hours to notify their 30 employees, most of them part-timers, and their customers. Firth said they held a staff meeting with employees, several of whom will go to work at Hacienda del Sol or Zone 78 on the east side. They posted a note on Facebook about the closing.

“When you reflect on Stray Dogs, we hope you remember all the fun: Enjoying over-the-top milkshakes, introducing the ginormous donut on the Food Network, winning Tucson’s ‘Best New Restaurant,’ cheering on the Wildcats. ... We couldn’t have done any of it without our amazing staff and patrons,” the posting read.

The owners went on to thank the dogs, the four-legged tag-alongs that set Stray Dogs apart from other restaurants in the North Stone Avenue/West River Road corridor. “Dogs” in the restaurant’s name had little to do with hot dogs; the menu mostly leans to burgers and the signature decadent milkshakes that married milkshakes with other desserts including apple pie, Rice Krispy Treats, cupcakes and doughnuts.

Dogs also are welcome at Zona 78, 7301 E. Tanque Verde Road, the spinoff of the original Zona 78 that the partners opened in 2008.

Firth would not name the buyers, but said the 3,000-square-foot space will not house a restaurant.

Meanwhile, Stray Dogs’ furniture, dishes, silverware and small and large appliances will be sold at a liquidation sale from 7 a.m. to 4 p.m. Saturday, Jan. 20, and Sunday, Jan. 21. For updates, visit facebook.com/straydogstucson

Contact reporter Cathalena E. Burch at cburch@tucson.com or 573-4642. On Twitter @Starburch