According to an analysis conducted by the National Association of Home Builders (NAHB) of the U.S. Census Bureau’s Survey of Construction (SOC), slab foundations were utilized to construct nearly eighty percent of new single-family residences that were initiated in 2025.
The proportion of homes constructed on slabs remained constant at 73% from the previous year, indicating that the use of slabs continues to be significantly more prevalent than other forms of foundations.
In the interim, the proportion of new single-family homes constructed with full or partial basements continued its long-term decline, with a 0.6 percentage point decrease to 16.4%.
Conversely, the proportion of crawl spaces increased by a mere 0.5 percentage points from 2024 to 9.7%.
The type of foundation remains consistent with the climate patterns of the region.
Basements are more prevalent in colder northern regions, where building regulations mandate that foundations extend below the frost line.
Full or partial basements comprised 67.7% of new single-family dwellings initiated in New England (67.7%), 64.4% in West North Central, and 48.7% in the Middle Atlantic in 2025.
West North Central had the largest average finished basement area of 957 square feet (sq. ft.) among these three divisions, followed by Middle Atlantic (830 sq. ft.) and New England (810 sq. ft.).
Nevertheless, each was less than the national average for a finished basement area, which is 1,143 sq. ft.
In warmer regions, slab foundations are generally preferred due to their affordability and efficiency.
In 2025, slabs were utilized in the construction of nearly all new single-family residences in the Pacific (86.0%), West South Central (97.7%), and South Atlantic (85.7%) divisions.
In certain northern divisions, the cost advantages of slabs have also resulted in an increase in their adoption.
The most apparent change was in the East North Central division, where slabs surpassed basements as the most prevalent foundation type in 2025.
Just over half of the new single-family homes that were initiated in the division were constructed on slabs, while a substantial proportion of the homes were still constructed with complete or partial basements, accounting for 43.0% of the total.
In contrast, the foundations of crawl spaces have generally been decreasing.
Despite the fact that the East South Central and Pacific divisions have historically been the primary users of crawl spaces, they both experienced significant declines in the wake of the pandemic.
The percentage of crawl space in the Pacific division decreased from 45% in 2012 to 12% in 2025.
The Mountain division has experienced a gradual increase in the utilization of crawl spaces, which is in contrast to the previous trend.
In 2025, its share of the market reached 20%, the highest since 2007, and it was ranked second among the nine Census divisions.
In contrast, the construction of crawl spaces has been consistently low in divisions such as East North Central, New England, and West South Central, with a share of new homes that have been started being less than 10%.
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