Ruth Eldridge's 19th-century townhouse was reimagined in the 1960s by acclaimed mid-century-modern architect Frank Weise, who built a jaw-dropping signature spiral staircase.

More recently, she updated the house with 21st-century modern conveniences.

In 1994, Eldridge moved into the house on Pine Street with her husband, Cary DeWitt Eldridge. They were academics, traveling to and from Paris to conduct research, and bought the house from a Temple University colleague of his, philosophy professor Sid Axinn.

The three-bedroom townhouse was built around 1828-29, but was modernized by the late Weise. The staircase was the centerpiece of Weise's design - it draws the eye upward through three stories.

Ruth Eldridge embarked on her refreshing of the house a few years back. To warm up the modern-design feel, she hung antique central Asian carpets and other textiles vertically along the walls. To blend the old and new, across the brick fireplace, which extends up to a cathedral ceiling, she hung her grandfather's and uncle's military swords, one manufactured by Harding Uniform & Regalia of Boston and dated 1915.

To finance the renovations, Eldridge took out a $100,000 home-equity loan. She redid the kitchen, the first-floor powder room and the roof, replaced the furnace, relined the fireplace, and refinished the basement.

Contractors included Kevin Waggle of Huntingdon Valley, "for heavily lifting," and Peter Baumann for the powder room, cabinetry and tile work.

"They're experienced, and they did everything right the first time. They've never had to come back," she said.

Eldridge's main concern was maintaining the fantastic light that comes into the house. "I didn't want to do anything to interfere," she said.

From her bedroom on the second floor, she has a view not only of Pine Street but also, through a transom window, to the backyard garden. At 1,750 square feet, the house feels large because the rear of it is built with walls of windows.

"Weise remodeled this house and the one next door to show what could be done, because in the '60s this neighborhood was considered a slum," Eldridge recalled. Built as a model of what could be, Weise's design for the Camac Village development "was an anchor village that was supposed to show how to turn around Philadelphia."

The front entry has a long hallway and includes a tiled powder room that contractor Baumann converted from a clothes and coat closet.

"We weren't using the space, and he installed a pocket door," Eldridge said.

She employed Middle Eastern-style tiles collected in her travels to surround the small sink.

The kitchen's redesign was done by Susan White, of Beco Kitchens in Morrisville.

White "squeezed every centimeter out of that floor plan, provided the cabinets, helped me choose the countertop," Eldridge said. She splurged on the granite breakfast bar leading into the kitchen, and again made use of natural light.

A see-through glass cabinet was installed that "allowed me to be a part of our gatherings when we had guests. It helped, so no one had to be banished to the kitchen."

Baumann smoothed the way from the living room's original hardwood floors into the kitchen's tile floor with a tiny elevation.

Then Eldridge turned to renovating the back of the house. Two sets of sliding doors lead to a secluded patio, which she also remodeled.

She added Pella windows for energy efficiency throughout the house, choosing the top-of-the-line brand, called Proline - double-glazed, with divided-light wooden frames. Dan Mehan, of Mehan Custom Builders, installed those and designed the front windows in line with what the Philadelphia Historical Commission wanted.

Finally, she converted the finished basement into an in-law/au pair suite.

"Kevin Waggle redid the foundation in two days," Eldridge said, "and it's nice enough that even my mother has stayed down there when she's visiting."