The first time Dan Bergeron toured the above-the-garage apartment that he was to reimagine into something that fit with the rest of the homeowners’ colorful home, he was transported back in time to the early 2000s. Shades of brown and blue were abound and geometric patterns were plenty.

“It was clear that the space hadn’t gotten much love in a long time,” the DB Interiors decorator notes. “That ended up being to our advantage because we could basically start from scratch.”

Over the years, the apartment had seen long-term guests following things like hurricanes, as well as countless slumber parties for the homeowners’ two daughters. But with the girls now grown up and out of the house, Bergeron says the homeowners felt it was time to find a way to utilize that space again.

“They originally told me that they wanted to just update and refresh the space for guests,” he recalls. “But as we got to talking and time passed, it made more sense to tailor the space to their two young grandsons who would use the space weekly, rather than infrequent guests who might stay up there every once in a while.”

With the switch of focus from adults to children, Bergeron says a world of possibilities was unlocked.

“The overall goal I had was to mix as many design styles as possible,” he notes. “I wanted it to be a space of imagination—something stimulating, unexpected, bold. And with these homeowners, there were almost no nos. Basically, if I could dream it, I could do it.”

His first consultation for the space saw him pitching using not one, not two but three different patterned wallpapers. Each in the same blue color family, the papers—all Schumacher—feature everything from running cheetahs to stars mixed with velvet polka dots.

“With the angles in the space, we needed to break it up with multiple patterned wallpapers,” he explains. “They’re whimsical but classic, which was what we were going for. We wanted the wallpapers—and everything else we chose—to be appropriate for kids but not ‘kiddie’ so that it would not only grow with the grandkids but also be a place that the entire family wants to come to sit and hang out.”

Shades of blue corresponding with the wallpapers cover the remaining walls, while a bright cherry red covers the trim, millwork and stairs. Pops of red are carried to the bathroom, where red and white subway tiles are arranged in a stripe pattern, as well as the small kitchenette with the selection of a backsplash tile featuring dainty red stars.

“It works because the colors are all in the same family,” Bergeron says. “It feels cohesive.”

More color was brought in through yellow velvet swivel chairs and window seat shade fabric featuring horses and a bright shade of orange—an homage to the homeowners’ love of Hérmes. Down the stairs, a gallery of bright artworks, including a signed George Rodrigue Blue Dog print titled Angel Baby and a large work Bergeron refers to as “the confetti painting,” add even more interest.

“The things we chose won’t just go out of style,” Bergeron says. “They may not be neutral, but I think they’re timeless.”

Look hard enough and pieces of Bergeron’s own childhood are sprinkled throughout the room’s design, too. The plaid runner on the stairs is inspired by Bergeron’s love for the pattern and his obsession with having a plaid-covered room as a child. In the lofted bunk area, a leather and brass Ralph Lauren sconce also speaks to a love for classic, equestrian style that Bergeron has had for as long as he can remember.

“I think on paper, this room seems like it has a lot happening,” Bergeron says. “But when you’re in it, it feels right.”

And that feeling comes not from the space looking pristine, with everything it its place and no trace of the fun that happens within its walls. Rather, the design comes together with toys strewn across the indoor-outdoor rug, a Maileg mouse castle set up beneath a pinball machine, and remote-controlled cars jetting across the open floor space.

“Kids should grow up with nice things,” Bergeron says. “I firmly believe that. This room has so many nice things, but it also still allows them to have fun in it—and that’s the most important thing.”