The Zahoudanis family: (from left) Jack, Alexis, Peter, and Kelly.

Go for it, said Kelly and Alexis. They also approved less radical improvements—like tearing down the faux-Colonial, painted-wood fireplace mantel in the great room so that the home’s original, minimalist brick hearth would be exposed; swapping the flimsy hollow-core interior doors for solid wood ones; and replacing the retro “clamshell” window and door trim with a more subdued, rectilinear design.

“I try to do the thing that really seems right for the house,” says Helgerson of her design sensibilities, “to be accurate from a period perspective, and to attend to how the house is going to flow and function.” But once that’s accomplished, “portable” things like wall coverings, furnishings, light fixtures, and art “can go in a completely different direction,” she adds.

Ergo, bold arboreal-motif wallpaper in the main-level powder room; a dazzling mirrored cabinet on the prominent upper stair-landing; and an array of fun light fixtures hanging throughout the house, including a curvaceous Le Klint pendant and industrial-chic, hanging glass blobs made by Niche Modern. From the planks of a sugar maple—a Portland street tree that had been felled—Doulis designed and built a coffee table, which now serves as the living room’s centerpiece.

These days, Helgerson revisits her handiwork often, since she, Doulis, and their kids have become good friends with the Zahoudanis clan. Post-remodel and redecoration, it’s hard to believe this beautiful house was ever a “dog.” Or, for that matter, that Kelly and Alexis Zahoudanis ever would have chosen the Santa Monica Freeway fast lane over their 25-mile-per-hour Southwest Portland loop.

“It’s surreal to like your neighbors so much,” says Kelly of her new, nonphilistinish community. “We have picnics on Thursday nights in the summertime. There’s a woodsy area down the street with a creek and a tree house. The kids run around, looking for worms and stuff, while the parents sit around and drink wine.” If it happens to be California chardonnay on occasion, we won’t tell.