Lee McColgan's career in finance was probably doomed as soon as he started visiting historic house museums. The first one he toured was the Fairbanks House, in Dedham, Massachusetts, the oldest surviving timber-frame home in America, built in 1637.

It was 2014, and McColgan was living in Omaha, Nebraska, where he worked as a sales representative for a large investment company. Despite a rural childhood in Vermont and an interest in visual arts and building, he had spent much of his adulthood working in a cubicle: five years of "jacking in" at a call center outside Boston, followed by several more as a Midwestern "external wholesaler" pitching mutual funds to financial advisers.

In quiet desperation, McColgan took up woodworking as a creative outlet, building an oak chest in his garage. That experience, and the visits he made to historic houses whenever he was back in New England, inspired him to reassess his life and envision a different future, working with his hands.

He especially appreciated the solidity of early Colonial-era building: the big, hefty beams that can last hundreds of years, so long as bugs and moisture don't get them; the dry-stone foundations that won't weaken as long as the roof is kept in good repair. He was obsessed with quality and hated "cheap stuff."

In 2017, McColgan finally quit his finance job and began a fledgling new career as a contractor specializing in the preservation of historic homes and buildings. To teach himself the trade, he did something impractical and possibly ill advised: He bought a very old New England Colonial in rough shape and set out to restore it using period techniques.

Not only that, but McColgan and his wife, Elizabeth Bailey, decided to live in the house while it was a work zone and laboratory. That difficult, educational, ultimately transformative adventure is the subject of his new book, "A House Restored: The Tragedies and Triumphs of Saving a New England Colonial."

"No kids and a supportive spouse," McColgan, 43, said on a recent afternoon, explaining how he was able to embark on such a quixotic pursuit.

He was sitting in a high-backed armchair in the front hall of the antique home he bought and restored: the Loring House, built in 1702 for Thomas Loring III, in the town of Pembroke, Massachusetts. Dressed in jeans, a tight black T-shirt and sneakers, he looked incongruously modern in the early American interior, with its low ceilings, brick hearth and spartan Colonial-style furniture. It was a sunny afternoon, but the house had a shadowy coolness typical of homes of the period — premodern air-conditioning.

As prospective buyers, McColgan and Bailey, 37, a director of development at the Archaeological Institute of America, had toured the Loring House "with childlike wonder," he writes in the book, marveling at the unexpected elegance of the fluted, carved pilasters on the front doorway and the hidden closets and secret rooms (a result of multiple additions over the centuries). They imagined themselves stabling horses on the 13-acre property that sits along a country road dotted with farms.

The couple bought the house for $550,000, from a woman in her 90s. They weren't blind to its issues, including a sagging roofline, but McColgan thought, "Light cosmetic work. Nothing more."

That changed quickly once they moved in and he got to work.

In the book, McColgan describes floorboards that "pitched and rolled, tossing me around as though a ship in rough seas." An exaggeration for dramatic effect, one assumed, until he got up and led the way into the dining room. There, the wide pine floors sloped the way mountains do heading into a valley. An antique oak dining table straddled the gulf in the middle.

In the kitchen, McColgan encountered a bigger problem. "I tear this wall panel off, and a section of the frame is just dust," he recalled, describing how one corner of the timber frame had completely rotted. "This is Week 1. I thought, 'How is this standing?'"

Elsewhere, he discovered a punctured foundation, frozen pipes, deteriorating bricks in the seven fireplaces and shattered windows.

"I realized I can't do this on my own," he said.

So he reached out to local experts in the niche world of historic preservation, including Michael Burrey, who teaches preservation carpentry at North Bennet Street School, a private vocational school in Boston, and owns a restoration business. For one summer, McColgan served as Burrey's apprentice.

In his quest to learn how to work with the six basic materials of the early 18th century — wood, lime, iron, stone, glass and brick — McColgan tagged along with a plasterer on Nantucket for a week and took a dry-stone walling course at the Carving Studio & Sculpture Center, in West Rutland, Vermont.

"He was one of the workshop participants who had a goal," Dan Snow, the dry-stone wall expert and sculptor who taught the course, said of McColgan. "He wanted to know specific answers to questions that he had about his home's stone foundation. He was really taking it on."

McColgan also hired himself out as a laborer to a man who specialized in refurbishing windows. Through that job, he got to work on Louisa May Alcott's Orchard House, in Concord, Massachusetts, and Old North Church in Boston, two landmarks of early 18th-century architecture.

"We pulled every window and brought them back to a little shop and cleaned them," McColgan said. "Some of the most boring work, but interesting properties."

Describing his chosen trade, he added, "A framing chisel and a mallet — you don't see those on a modern construction site. This world still lives on the fringe."

Slowly, McColgan gained a footing in his new career — and under his own roof. He started a business, Helve Historic Trades, and now primarily works on historic museum properties. (One recent job was restoring the woodwork on the cupola of the Mayflower Society House, in Plymouth, Massachusetts.) And he continued to bring the skills he learned on job sites back home.

There is a divergence of opinion in the world of old houses, a conflict between preservationists who are sticklers for historical accuracy and those who prefer a certain level of modern comfort. With the Loring House, McColgan sought to preserve the historic details, leaving them largely untouched, while doing only the repairs necessary to make the structure sound and livable.

Thus, the floors still pitch and roll in many rooms, and the wall paint with its gloomy shades of gray and mustard yellow is positively ancient. But he replaced the rotted kitchen beam with a new "in kind" piece — oak where oak had been — and shored up a 2-foot-long fracture running through the brick fireplace in the living room.

The plumbing and heating had been updated in recent years, so McColgan did no modern construction, which is how he prefers it. "I want to be doing the framing and the brickwork and the blacksmithing," he said. "That's the stuff I'm interested in."

But at the back of the rambling house is a surprise: a light-filled living area with high ceilings and a floating steel staircase rising to a loft. The space existed already, but McColgan added the staircase and otherwise altered the layout. The room is as startling in this old, old house as the owner in his jeans and sneakers.

"You can sit back there and be in the modern age," McColgan said. "And then you walk back into the kitchen, and you're in the 18th century."