During the 1960s and 1970s, several Tri-Valley builders experimented with a strange suburban compromise: houses that weren't fully finished yet.
Buyers could purchase a smaller, more affordable home upfront, then complete unfinished upstairs rooms later as budgets and families grew. In some models, builders even sold the staircase separately.
For a brief period, expandable homes appeared across Dublin, Livermore, Pleasanton, and San Ramon—marketed under names like the Room Maker, Spacemaster, and Now and Future House.
Expandable homes reflected a particular optimism of postwar suburbia. Rather than paying for every square foot on move-in day, families could buy the space they needed now and finish the rest later. Builders marketed these homes as practical investments that would grow alongside young families, turning unfinished attics and bonus rooms into bedrooms, family rooms, or hobby spaces years down the road.
The concept also reflected the realities of the era. Thousands of first-time buyers wanted new suburban homes, but rising prices forced builders to find creative ways to keep monthly payments within reach. Selling part of the house unfinished reduced the initial purchase price while giving homeowners the option to add living space later, often with materials or plans supplied by the builder.
Although the idea never became the dominant way of building homes, it spread surprisingly widely across the Tri-Valley. Different builders gave the concept different names and floor plans, but they all promised the same thing: buy the house you can afford today, and finish the rest when life catches up.
Model homes took two very different approaches to selling the idea. Some showcased beautifully finished bonus rooms to help buyers imagine the possibilities. Others did exactly the opposite, leaving the space unfinished so visitors could picture their own future taking shape there.
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| One way to sell the dream: William Lyon Homes finished this expandable bonus room as a bright recreation space, helping buyers picture how the extra square footage might someday become part of everyday family life. |
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| Not every builder staged expandable space the same way. Rather than decorating the room, American Housing Guild left this Appletree bonus room unfinished, placing only a solitary antique sewing machine beneath the exposed rafters. The sparse presentation emphasized possibility over polish, leaving buyers to imagine the room's future for themselves. |
Expandable homes across the Tri-Valley
Dublin: unfinished upstairs living
Parkwood by Monarch Construction (1962)
One of the earliest expandable designs came from Monarch Construction in Parkwood San Ramon.
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| The Plan 3 model at Parkwood featured an entire second floor as a “bonus room.” Imagery via Google Street View. |
Appletree by American Housing Guild (1967)
The Room Maker model introduced an unfinished second story that included windows but unfinished, highlighting the do-it-yourself nature of these homes.
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| The Room Maker model at Appletree offered affordable flexibility for growing families with an unfinished second-level so buyers could expand later. |
Livermore: the peak of the expandable home
Somerset Homes by H. C. Elliott (1968)
The original Somerset House offered a two-bedroom layout with an unfinished second story.
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| Somerset House with flexible design—stairs and windows sold separately. Imagery via Google Street View. |
A revision of the Somerset House, the 1969 Spacemaster included blueprints and a kit for a 500 sq. ft. second story. In 1970 it came with pre-installed second-story windows and a DIY staircase kit.
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| The Spacemaster: offering blueprints, windows, and a staircase kit for future upgrades. Imagery via Google Street View. |
Pleasanton: the “Now and Future House”
Valley Trails by Morrison Homes (1970)
Morrison’s Now and Future House lived up to its name with a design that could be purchased as a finished 4-bedroom or left at a 2-bedroom starter.
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| The Now and Future House in Valley Trails gave buyers a choice: grow now or later. |
San Ramon: bonus rooms and future bedrooms
Country Club Park by Volk-McLain (1962)
The Woodside model offered an upstairs “bonus room” or up to three additional bedrooms and a bath.
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| Woodside model in Country Club Park, San Ramon, with flexible second-story potential. Imagery via Google Street View. |
California Classics by William Lyon Homes (1968)
The Look Ahead House included a convertible second story that could be finished later as two more bedrooms.
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| William Lyon’s Look Ahead House included an unfinished second story that could later become two bedrooms. Imagery via Google Street View. |
Why expandable homes disappeared
Expandable homes gradually faded from new subdivisions by the late 1970s. As household incomes rose, mortgage financing evolved, and buyers increasingly expected move-in-ready homes, the appeal of purchasing unfinished living space declined. Families still wanted room to grow—but they wanted it finished from day one.
The idea didn't disappear entirely. Instead, it evolved. Builders continued designing flexible floor plans with bonus rooms, lofts, and, more recently, "flex spaces" that could become home offices, playrooms, guest bedrooms, or media rooms without requiring homeowners to complete the construction themselves.
Today, many original expandable homes are almost impossible to recognize. The once-empty spaces have become bedrooms, family rooms, hobby spaces, or rental units, making these houses appear little different from their neighbors. Only subtle clues—such as rooflines, window placement, or floor plans originally designed for future expansion—hint at their unusual beginnings.
For a brief moment in the history of Tri-Valley suburbia, builders treated the tract house as something unfinished by design: a home intended to grow alongside the family that lived in it.
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