After almost a year of construction, the Hacienda del Sol Guest Ranch Resort is less than a week away from making 32 new rooms available to guests, bringing the boutique hotel’s room count to 60.

The development, part of a $13 million project, brings the first new construction in 50 years to the foothills property that began life as a school for girls in 1929 and later became a guest ranch favored by golden age Hollywood stars.

The expansion is driven by economics, said Tom Firth, managing partner at the resort.

“In the high season, we were turning guests away because we only had 30 rooms,” he said. “We’re bullish on Tucson. Why would you do this if you didn’t feel good about our region?”

While the final phase of the project, a 5,000-square-foot ballroom, will be completed by early next year, most of the changes are complete.

Along with the new rooms, the Hacienda now boasts two paved parking lots, new administrative and maintenance buildings, a circle driveway with valet service, and an expanded garden patio and lounge, complete with a retractable roof.

A new infinity-edge pool is set to open at the end of November.

Operating during the construction has been challenging, Firth said, but both the staff and guests have been understanding throughout the process, which ended up being four months behind schedule.

Most of the delays, he said, came at the beginning, when crews ran into underground utilities no one knew existed.

“This property is 86 years old, so back then probably a lot of things were done over the years without permits,” he said. “But it’s exciting to be at this point now because we can see the finished product and so can our guests.”

Making sure there was continuity between the resort’s historic buildings and the new construction was a priority, said Susan Kowalcek, marketing director at Hacienda del Sol.

Not only was the building style respected, the interiors of the new rooms match a lot of the Southwestern style in the historic building.

As part of the project, all rooms were remodeled and got matching furniture that was designed by hand and custom-made in Mexico. The new rooms also have a hand-painted border along the ceiling, Talavera-style tile insets and hardwood floors.

The goal, Kowalcek said, is to offer guests a unique stay.

“Guests are looking for an authentic Tucson experience but they still want all the comforts and luxuries that they’re used to,” she said, and the new rooms do not disappoint.

The rooms offer king or queen beds, 55-inch flat-screen televisions, Keurig coffee makers, high-speed Wi-Fi and custom bath and body products. All the rooms have balconies with views of the city and the Rincon or Catalina mountains.

At over 500 square feet, the rooms are also spacious enough to offer in-room spa treatments, Firth said, which comes in handy when guests want to continue their relaxation.

“We’ll be able to leave the table in the room, so when the treatment’s over the therapist leaves and you can take a nap or lie there for 20 minutes on the table,” he said. “Then just call us when you want it picked up.”

With the expansion and a commitment to an increased level of service, Hacienda del Sol is ready to compete with other high-end luxury resorts such as Royal Palms Resort and Spa in Phoenix or L’Auberge in Sedona, Firth said.

“That boutique luxury hotel market, that’s really where we want to be,” he said.

Contact reporter Luis F. Carrasco at lcarrasco@tucson.com or 807-8029. On Twitter: @lfcarrasco