First, cut sharply off a two-lane road leading around Italy’s Lake Como and dodge the local stray cats until you hit a cobbled lane lined with scruffy mulberry trees. Follow this to its end. Then, on your left, you’ll see the stucco facade of an apparently anonymous edifice — an ocher two-story rectangle overlooking a simple walled garden and lawn, the lake just beyond them. This is La Filanda (the Mill), the name a nod to the 9,600-square-foot building’s original 19th-century function as a silk-weaving factory. Only a small nameplate — that says simply “housekeeper”— hints at the place’s current residential use. “We felt it was more interesting having something beautiful inside that nobody knows,” says Federico Marchetti, 49, the Milan-based entrepreneur behind the Yoox Net-a-Porter online retail empire. For the past four years, he and his partner, the British journalist Kerry Olsen, 41, have devoted themselves to constructing this privately opulent weekend refuge on a stretch of lakeshore best known for the palaces of American movie stars and Russian oligarchs.​

In this they had an unusual collaborator: Luca Guadagnino, the Italian filmmaker, who had always wanted to be an interior designer. Marchetti knew of that dream from an interview that Guadagnino, 47, once gave; while Marchetti was visiting him on the set of “Call Me by Your Name” in 2016, he proposed that they collaborate on the house with the architect Giulio Ghirardi. Despite being in preproduction for his next project — a reimagining of the director Dario Argento’s 1970s Italian cult horror classic “Suspiria,” to be released in November — Guadagnino immediately agreed. “I’m a little bit irrational,” he admits.​

Marchetti and Olsen had long been friends with the director, whose densely atmospheric film sets are memorable for their layered, subtle details: a barely seen armoire full of linen in 2009’s “I Am Love;” an actual notarized land deed used instead of a facsimile for 2017’s “Call Me by Your Name.” Guadagnino often films his movies in aristocratic villas or Art Deco-era wonders little known outside of Italy — environments are as critical to his vision as actors or scripts. “Space is the most important thing that comes to my mind when I analyze things,” Guadagnino says. “In cinema, you are an impostor, in a way, because you can always edit afterward and change the story. You cannot do that with a house.”​

A house, after all, is not a fiction. And far from being theatrical types, Marchetti and Olsen envisioned their life at La Filanda as one oriented toward family and domestic pleasures. Marchetti, who was born and raised on the Adriatic coast, in Ravenna, is attracted to water and loves to swim. Olsen, from the north of England, enjoys gardening: Guided by Guadagnino’s colleague, Gaia Chaillet Giusti, she planted modest parterres in a chevron pattern, had two mature palms helicoptered onto the property from nearby Tremezzina and installed a dollhouse-like structure for the family’s pet tortoise, Frittata.​

Inside, the couple sought a harmonious retreat. Guadagnino started with a psychologically detailed questionnaire: What colors do they like? What time of the day do they prefer? How do they see themselves in a room? Answers in hand — bright jewel tones, mornings, playing board games with their 7-year-old daughter, Margherita — the director began composing a storyboard in the form of a workbook, a thick volume that encompassed a minutely detailed inventory of the exemplary collection of 20th-century furniture that Marchetti had been amassing for years. “I’m a storyteller,” Guadagnino says. “That’s my first job.”​

Though skilled at creating sumptuous movie sets, the director is neither a trained architect nor an interior designer. Along with a general contractor, the 150 Italian craftspeople Guadagnino assembled like a crew executed his design for the brass-trimmed, ribbed oak paneling used on the lower part of some walls (inspired by, Guadagnino says, “a very precious wood box, the kind you can find in Japan”); upholstered those same walls above the dado with Kvadrat wool fabrics in geometric panels in reference to both the structure’s origins as a textile factory and its mid-20th century Modernist design; and applied in stucco at the cornices a motif of double-ended ogives, a vaguely maritime style that alludes to the lake visible beyond the brass window frames. Still, La Filanda isn’t baldly literal in its references. While it is tempting to think of the place as engineered with the taut economy of a yacht interior, the house more accurately evokes a puzzle, one whose interlocking pieces seamlessly, and seemingly inevitably, fit together.​

Before Guadagnino began, the couple had already gutted the building, which was constructed more than a century ago during a boom in an industry first begun at Como in the 1400s, when Ludovico Sforza (then the Duke of Milan) commanded that the lakeside be planted with mulberry trees for the delectation of silkworms. (Until as recently as the 1970s — when the industry migrated to China — silk remained the area’s most important commercial export.) In the decades after the shuttlecocks stopped clacking through looms at La Filanda, the mill was used as a tennis racket factory, then as an auto repair shop and, finally, as a depot for boat motors before sinking at last into pigeon-haunted desuetude. It was the building’s shoe-box shape that inspired Marchetti and Olsen to acquire it five years ago, after having spotted it on strolls from their nearby rental.​

If executing their vision would prove complex, the impetus for the home’s purchase was simple: “My dream was always to have a pool,” Marchetti says. Originally intended for the ground floor, it was relocated to the basement after workers discovered that the soil beneath the building was contaminated with lead and would need to be removed. After the subterranean bathing pavilion was completed, the house’s transformation picked up pace, Guadagnino filling the home with treasures accumulated by the couple as well as pieces he found for them.​

Guests enter La Filanda at the structure’s midpoint, a sunlit foyer dominated by an immense Claude Lalanne Bagatelle mirror framed in looping bronze tendrils and hung above a matching Lalanne console. For Marchetti, the pair of bronze mice he specified to scurry up the table’s struts are as much a source of pleasure as the Giorgio Morandi still life from the 1950s that he impulsively purchased from an online auction and that now hangs in the ground-floor powder room.​

To the left of the entry, there’s a pantry whose lacquered pistachio cabinetry is branded Studio Luca Guadagnino, the filmmaker’s new design firm, and is rendered, like so much else in the house, in the confectionary hues of Jordan almonds. Beyond this is a kitchen with custom-paneled shelves in varying tones of yellow (also created by Guadagnino’s firm) alongside an enormous suspended lighting fixture created in 1933 by Gio Ponti — merely one example of Marchetti’s irresistible attraction to every imaginable form of artificial illumination.​

Extending toward the lake, the main 62-by-20-foot living area, which spans nearly half the length of the structure, is divided into three discrete zones of seating. What is most notable in each is how Guadagnino has arranged — as though a group of actors were conversing in a scene — decorative elements as disparate as a rugged 1960s George Nakashima slab table, a 1950s sycamore and rosewood Italian bar cabinet, caned chairs copied in Mumbai from early 20th-century designs by the French architect Maxime Old and a colossal 2009 photograph by the German artist Candida Höfer of the national library in Naples. A helipad-size marble table, custom built by Hermès, anchors the room. (With bespoke waxed-leather legs, it’s a marriage of Guadagnino’s passion for the handmade and the retailing mogul’s acquisitive appetites.)​

Together, the designer and homeowners also plundered the archives of venerable European manufacturers. At the Nymphenburg Porcelain Manufactory in Munich, Guadagnino and Olsen unearthed a disused French rose glaze to color a portion of their 303 pieces of china, some of which feature a pattern designed two centuries ago. At Manescalchi, a linen purveyor favored by the Milanese haute bourgeoisie, Guadagnino found from dead stock a collection of pristine place mats and napkins with elaborately handworked fagoting details. At J. & L. Lobmeyr glassworks in Vienna, he commissioned gossamer glassware etched with outlines of Lake Como.​

As with his films, a second take was sometimes required. At the core of the house is an oak stairway resembling the interior of a chambered nautilus that links all three floors. Built once in its entirety, it was torn out and recreated after the original curve was judged to be clumsy. In keeping with the house’s palette, the treads are covered in a bespoke rainbow ombré carpet from France’s Gobelins Manufactory, the colors of which increase or diminish in intensity — yellow to orange to red to blue to green — as you ascend to the bedroom floor or descend to the screening and changing rooms at the pool level. “Even though the house is contemporary, it’s also meant to be a sensual place,” Guadagnino says.​

This is most evident on the private upper level, where he designed cocooning spaces for each occupant, appointing the master suite with furnishings either quirky (reproductions of a pair of wavy 1940s Paolo Buffa night stands), austere (an Hermès re-edition of a 1924 Jean-Michel Frank parchment dressing table) or, as with the textured Cogolin rug, seductively tactile. Connected by a hallway that runs the length of the house, there are three bedrooms — one each for parents, daughter and guests — along with a study, a library and Olsen’s boudoir. (“Finally,” she says, “I have more closet space than Federico.”) It is in these rooms that Guadagnino seems to pay frank homage to one of his greatest influences: Villa Necchi Campiglio, the magnificent Milanese manor designed in the 1930s by Piero Portaluppi for two heirs to a sewing machine fortune, in which “I Am Love” was filmed. As with that house, the hand of a decorative mastermind appears in every detail at La Filanda. Throughout, cultivated restraint takes the place of ostentation. “Of all the great houses you could find on the lake, Federico and Kerry decided to go for this old factory,” Guadagnino says. “Here, everything important is inside.”​