Houzz Tour: Modern, Ecofriendly Prefab in Seattle

The family maximizes every square inch of space in this house. Each functional zone is clearly defined but has multiple uses to conserve square footage. This approach enabled Johnston and her team to build a more compact and efficient house with fewer materials; it also requires less energy to heat, cool and maintain.

The kitchen and living room cabinets are formaldehyde free. "Although these particular cabinets were sourced from Italy, we've since learned that local shops are working with formaldehyde-free plywood, so we're sourcing locally from here on. Trust that the cabinets were shipped with green tags to offset carbon emissions," says Johnston.

Couch: Togo, Ligne Roset

The house was assembled onsite from a kit in a little more than seven months. This image shows the two-car garage with Sam's office above, the natural wood shiplap siding and the chartreuse HardiePanel — all low-maintenance materials that were carefully detailed to resist the elements gracefully.

"Sam's home office above the garage is a real workplace for him. He telecommutes some days of the week, which saves on his commute time and gas and gives him more time with his family," says Johnston.

Roll-up doors connect the kitchen and dining area to the outdoor patio and pool area. The doors serve as large windows when closed, and when open, they disappear entirely, blending the outside into the inside. Johnston says, "The roll-up doors have a commercial and industrial look and feel to them but are entirely appropriate and economical to use for this home."

The dining table, windowsills and stair treads came from a fir tree that was on the property prior to construction.

The Guckenheimers' home, along with all Place houses, was made with materials that are nontoxic and low in volatile organic compounds (VOCs). It's equipped with low-flow plumbing fixtures to conserve water and with Energy Star–rated appliances.

"This family is all about flopping on the couch together, living and working and doing all the things that families do in the home. But they also love their individual spaces, being able to read quietly somewhere or watch a movie in the living room. The layout of this house works for them and is an articulation of their love for each other," says Johnston.

In-floor radiant heating is cost effective and runs off the same boiler that supplements the heat for domestic hot water. The floors are made of structural concrete slab, which minimized the layers of material needed to finish out the space, cut down on waste and eliminated a layer of finish that would otherwise have to be replaced every 10 years or so.