The former ‘scaffolding house’ headlines the 2017 Mount Baker Home Tour

LIKE A SUBPAR BURGLAR, skeletal scaffolding crept up, down and around the historic Charles P. Dose mansion right in plain sight, for a generation — and never actually finished the job.

Architect Jeannie Iannucci, chairwoman of this year’s Mount Baker Home Tour, lives next door and eyewitnessed its incremental progress. “The owner loved the house and was very good at fixing it,” she says. “But the house is so old.”

That it is. Built around 1912, the staggeringly grand four-level Colonial Revival has been a showpiece of elegance for more than a century — and then the scaffolding came down; a for-sale sign went up; and Australians John Galligan and his husband, Jamie Gorman, moved here from Singapore.

“We wanted to buy and set roots,” Jamie says. “This was on the market a while. It was not love at first sight. It needed a little bit of love, didn’t it? It needed some attention. We thought we needed to start on the outside: only a tree, like an old lady that needed a new dress.”

They might have started on the outside (the new landscaping, by Peter Norris of Folia Horticultural + Design, is breathtaking), but trust us: A single dress is rarely enough. John is senior director of Microsoft’s global government affairs team, and Jamie is a furniture designer who owns The Shophouse in Singapore; together they have spectacularly and respectfully reoutfitted the interior of their 4,700-square-foot home — and now you may go inside.

Their storied mansion is the headliner of the Dec. 2 Mount Baker Home Tour, which supports the historic Mount Baker Community Club, whose current clubhouse was designed by Charles C. Dose (Charles P.’s son) and built in 1914.

There’s a lot of history here — and it’s been warmly embraced.

“It was fairly solid — more than solid,” John says. “Every owner must have taken meticulous good care; it’s got good bones. It was quality workmanship back then. We’re doing only a little bit of tweaking; we’re not compromising its integrity.”

Little tweaks, huge rewards: Gleaming new lights, floors and paint (no structural changes required) now brilliantly frame colors, materials and pieces with an exceptionally informed DIY perspective.

“I did most of the design and all the interiors,” Jamie says. “I’ve designed the sofas, chairs, sideboards, beds.” Adds John: “Almost everything here came from Jamie’s shop.”

At the formal and welcoming entry, the concrete stairs were redone, while the door handle (and door, minus the wood panels) is original. The former upstairs “sick room” retained its original light (but not its exterior door) and evolved into lovely, healthy office space. The dark wood of the three-panel doors (“They’re everywhere,” John says) was restored, and original fir floors restained and darkened.

In the first-floor dining room (previously “dark, with artificial metal panels,” Jamie says), smooth plaster, sheer paint and box beams perfectly blend with the original radiator; pocket door; built-in cabinets; and leaded, fruit-themed glass (a signature Dose touch, John says).

Upstairs, off the sitting area (which used to be a bedroom), “There’s a little Juliet balcony where we have our G&Ts in the afternoon,” John says. “Whoever gets up here first gets the left-hand chair. From May to November, we have a lovely view of the lake.”

And not a single intrusive project platform.

“At a fundraiser for a local school, our introduction to the neighborhood, there were all these kids who’d moved back,” John says. “They said, ‘Oh; you bought this house. It’s the first time we’ve seen it in 20 years with no scaffolding.’ ”