I’m asked all the time, which is less expensive to build? A one-story or two-story house?
Tough question that depends on a lot of factors. Construction costs are one measurement, but long-term lifestyle issues may be more important. Assuming you’re desire the same square footage on either one or two floors, the question becomes, do you want a sedan or a SUV? Each will result in different long-term consequences for both design and construction budgeting.
At first glance, a two-story would be less expensive since you have less foundation and roof areas. But it’s not that simple. The permitting, designing and approval processing for each floor added increases time and expenses.
As land becomes more expensive and lots become smaller, the option of a one-story plan may decline, forcing construction of two and even three-story structures. And yet, people want more square footage. Contractors know the more square footage they can add, the easier to spread the hard construction cost, such as plumbing, utilities and finishes, over a larger area. And often it’s better for the sales. Builders know buyers compare square footages when shopping, so lower costs per SF helps.
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Of course, there are advantages and disadvantage is to both. Let’s start with advantages and disadvantages of single-story construction:
— Safer to live, safer to build, less scaffolding or climbing
— Cheaper to design and engineer
— Easier to “age-in-place“; no stairs and easy to operate a wheelchair in the future
— Potentially could use fewer bathrooms when one story. Laundry room can be centrally located.
— More design options and easier to provide more ceiling height variations or skylights.
— Construction is generally easier with ease of perimeter access.
— A one-story plan will take up more space and provide you less outdoor living.
— The building exterior envelope is greater requiring more heating and cooling.
— One-story homes will require more insulation and require more energy conservation.
— Duct work and plumbing may be longer and less energy efficient.
Let’s look at two-story construction:
— In many instances the cost per square foot is less with a reduced amount of excavation/foundation and roofing area.
— A smaller footprint could provide more outdoor living space.
— You might capture better views, however privacy between neighbors could be compromised.
— A two-story building might have more ground floor porches, bay windows, and bump outs.
— A two-story home might have more internal privacy with more and separation for kids as they becoming teenagers.
— Typically, more fuel efficient, with shorter duct and plumbing runs.
The disadvantage could be:
— Engineering design and costly connections are greater, especially here in California where design must take into account earthquakes and wind forces.
— Since privacy between neighbors could be compromised, two-story homes may need design review approval, adding to the design schedule.
— Stairways are expensive. They could take up 100-150 SF of living area and cost anywhere up to $40,000.
— In order to get more interesting ceilings on the ground floor, you have to increase the floor-to-floor height which adds to the construction cost.
— Two-story houses can take longer to build and often require cranes to lift materials to upper floors.
— Exterior wall surface areas are about the same but two-story construction is more expensive to install.
While two-story construction appears to be less expensive and provide more advantageous for land use, it may not be as advantageous to the all homeowners. A one-story house can adapt to multiple generations from a young starter family to senior retirement. A two-story house may not be as adaptable to older inhabitants.
I always recommend to my clients they look at their long-term agenda. Do they plan to raise a family, downsize and move to another facility? Do they wish to have multiple generations living under one roof? In the future, will they consider making a portion of their house an apartment for a family member, a rental or for themselves in their twilight years?
Whether you decide to build a one-story or two-story home is dependent on a lot of factors that you need to consider with your architect and contractor. And, as land gets more scarce, more unusual land conditions become apparent. There’s a reason why there’s a vacant lot down the street. It may have soil problems, utility issues or privacy problems with neighbors.
One thing I tell all of my clients when they are looking at buying or building a home within any neighborhood is, talk to the neighbors. They will tell you more about a piece of property then you’ll get from professionals. Disclosures on purchases are just not enough. I always say, the more you know, the better your investment.
Chris d Craiker AIA/NCARB loves his split-level home as a compromise to a one or two-story home.