In the kitchen/breakfast room, vintage stools slide under the island, and oak chairs by Emil Lagoni Valbak pull up to a vintage French farmhouse table. Apparatus hanging light; Rose Uniacke sconce; Rohl sink fittings; Wolf range; artworks by Richard Serra (left) and Brice Marden (right).

Art: © 2024 Richard Serra / Artists Rights Society (ARS), New York.

That meant rethinking the approach, inside and out. Diaz + Alexander Studio, a development and architectural design firm in Los Angeles founded and run by Rob Diaz and Mark Alexander, had already constructed the foundation and frame. “The shape was there, so we worked with them on the finishes, to make it sustainable and bring it into the context of its environment,” Cassidy says.

They wired the house for solar panels, which will go on the roof, once they are delivered. “There’s a backlog in California—too much demand, which is great,” the designer notes. They put in double-glazed windows, which are required for new construction in California and “help thermal-insulate the house,” he explains. And they clad much of the exterior with responsibly sourced dove gray and sand-hued stone from Eco Outdoor in Los Angeles. “Light stone reflects light and keeps the house cooler,” Cassidy points out. “And stone lasts forever and is no-maintenance. If you think about the midcentury houses across Los Angeles, they always had stone walls. It’s nice that stone is back in fashion.”

For the interior walls, Valletta wanted to avoid conventional paint, which often emits volatile organic compounds, or VOCs—chemicals that can be carcinogenic. Instead, she and Cassidy chose natural clay plaster tinted with natural pigments by Clayworks of Cornwall, England, which was manipulated to create smooth and fluted textures. “In the summer, it stays cool,” Valletta says. “And in winter, it warms up and stays warm.”

A vintage French ceramic owl lamp with a rattan shade glows in the powder room. 1950s Paulo Buffa mirror; a 1950s Italian tailpipe sconce; pink marble countertop with integrated sink; Samuel Heath faucet.

The decor is eco-minded too. Rather than kit the house out with new furniture, Valletta reupholstered pieces she already had, like a pair of American-made BDDW chairs she bought from her friend the model Carolyn Murphy. “When Carolyn saw them, she said, ‘Oh, my gosh, they look so good! They have a great second life.’ ” So do Valletta’s old kitchen chairs: “They were black with leather seats, and that just wasn’t right for the house,” she recounts. “We scraped down the wood and found they were white oak, and re-covered the seats with beige linen.”