Octagon houses were a thing in the 19th century.

Thomas Jefferson built one, Poplar Forest, in Virginia in 1806. But the eight-sided design really took off in 1848 with the publication of "The Octagon House, A Home for All," by amateur architect Orson Squire Fowler. Fowler was an enthusiastic proponent of octagonal homes, which allow for better air circulation, let in more light and are more efficient to heat and cool than traditional square or rectangular homes.

The style became popular, particularly in New York, and a number of examples were built around the United States and in Canada, including one in North St. Paul, built in 1887, the year the village was founded as Castle. By then the octagon style was on the wane. It's the only surviving octagon house in Ramsey County, and one of only a handful in Minnesota, according to current owner Dave Sours.

He and his wife, Marilee Olson, bought the place, which is a block away from Silver Lake, 15 years ago. "It was in rough shape, definitely a fixer-upper," said Sours. But the couple were captivated by the home's unique character.

"It had a really happy feel to it," he said. "You could tell a lot of good times had happened there. It's got a good vibe."

Many of the home's Victorian-era features had survived, including original hand-carved corner blocks with Chinese dragon and floral motifs. An early owner, Ernst Reiff, who also owned a casket company, had had his casket painter lacquer the home's interior doors then paint fanciful designs on them, including Japanese fans, an oak tree with an owl and a moon, cattails with a spiderweb and spider, and rose vines.

Octagon house in North St. Paul is on the market for $485,000.

Over the years, Sours and Olson have enhanced the home's historic character while bringing it into the 21st century. They put in central air-conditioning, and rebuilt the porches. They refinished the oak staircase, and gutted an earlier addition to create space for an architectural salvage butler's pantry, a half bath and two closets.

They also completely remodeled the kitchen, adding marmoleum flooring, salvaged century-old walnut and birch cabinets, and a unique countertop. "We found a section of bowling alley lane. I edged it in walnut," Sours said.

The couple used period-appropriate details whenever possible, including antique light fixtures and hardware, and historic Bradbury & Bradbury wallpaper.

They also enhanced the landscaping on their half-acre lot. Olson created "amazing gardens, with lots of specimen plants," Sours said. They also restored a rock garden and rebuilt a waterfall.

Now that Sours and Olson have both retired, they've decided to move to a smaller one-level home in Stillwater. Their colorful three-bedroom octagon house is on the market for $485,000. In addition to 2,700 square feet on the first and second floors, there's also a finished third floor that could be converted into an owners' suite or studio.

Sours will miss their home's distinctive character. "For us, it's the period feel — like an old house but practical for modern living," he said.

"We took a place that somebody might have torn down ... and turned it into a real jewel."

Cheryl Larson, 651-270-0213, Coldwell Banker Burnet, has the listing. There will be an open house noon to 2 p.m. Aug. 4, 2609 18th Av. E., North St. Paul.