Original research
Foundation types by region
What new houses are built on in each Census region since 1971, and what the homes people live in now sit on.
Written by HyreFoundation Research Desk Primary-source research and fact checking
The finding
Foundation types by region split the country cleanly. In 2025, 75% of new single-family houses in the U.S. were built on a slab, 16% on a full or partial basement and 9% on a crawl space, per the Census Bureau.
The South builds 88% of its new houses on slabs, while the Northeast (53%) and Midwest (50%) still put about half on basements.
The homes people already live in look different. In the 2023 American Housing Survey, 37.7% of occupied single-family and manufactured homes had a basement, 34.9% sat on a slab and 19.4% on a crawl space. New England tops basements at 84.6%; the West South Central division (Texas, Oklahoma, Arkansas, Louisiana) tops slabs at 71%.
The headline numbers
What foundation do new houses get in each region?
Slab dominates new construction in the South and West. Basements hold on in the Northeast and Midwest, where frost lines are deep and a footing already has to go down several feet. Crawl spaces are a small share everywhere now.
| Region | New houses 2025 (thousands) | Basement | Slab or other | Crawl space |
|---|---|---|---|---|
| United States | 1,005 | 16% | 75% | 9% |
| Northeast | 66 | 53% | 40% | 7% |
| Midwest | 131 | 50% | 43% | 7% |
| South | 584 | 4% | 88% | 8% |
| West | 224 | 16% | 70% | 14% |
How has each region changed since 1971?
Every region builds fewer basements and crawl spaces than it did in 1971. The biggest swing is the South, where crawl spaces went from 38% of new houses to 8% and slabs went from 46% to 88%.
| Region | Basement 1971 | Basement 2025 | Crawl 1971 | Crawl 2025 | Slab 1971 | Slab 2025 |
|---|---|---|---|---|---|---|
| Northeast | 80% | 53% | 9% | 7% | 11% | 40% |
| Midwest | 72% | 50% | 14% | 7% | 13% | 43% |
| South | 17% | 4% | 38% | 8% | 46% | 88% |
| West | 15% | 16% | 23% | 14% | 62% | 70% |
What foundations do existing homes sit on, by division?
The housing stock changes slowly, so older patterns still show. Basements lead in New England, Middle Atlantic, West North Central. Slabs lead in West South Central, Pacific, Mountain. Crawl spaces are most common in East South Central and Pacific.
| Census division | Occupied homes (thousands) | Basement | Crawl space | Slab | Manufactured home | Other |
|---|---|---|---|---|---|---|
| United States | 100,662 | 37.7% | 19.4% | 34.9% | 6.8% | 1.2% |
| New England | 4,106 | 84.6% | 3.7% | 8.3% | 3.1% | 0.2% |
| Middle Atlantic | 10,964 | 78.1% | 6.7% | 11.1% | 3.2% | 0.8% |
| East North Central | 15,278 | 71% | 13.1% | 11.4% | 4% | 0.5% |
| West North Central | 7,206 | 73.7% | 11.8% | 8.6% | 5.4% | 0.6% |
| South Atlantic | 21,538 | 21.1% | 25.1% | 43.1% | 9.3% | 1.4% |
| East South Central | 6,853 | 20.4% | 36.5% | 31.6% | 10.5% | 0.9% |
| West South Central | 12,863 | 1.5% | 16.7% | 71% | 8.6% | 2.2% |
| Mountain | 8,136 | 29.5% | 14.3% | 45% | 10.1% | 1% |
| Pacific | 13,717 | 8.6% | 33.4% | 50.8% | 5.4% | 1.8% |
Why do regions build different foundations?
Three things drive it: frost depth, soil and water, and local building habit.
Where the ground freezes deep, footings must sit below the frost line, so digging a little further for a basement adds usable space for the extra excavation.
In warm, flat places with a high water table or clay soil, a slab poured at grade is the default.
Crawl spaces were the Southern standard in the 1970s and are now a minority choice even there. Our crawl space vs slab comparison covers the trade-offs, and foundation types explained walks through how each one is built.
This data says what was built, not what is best. Whether a foundation suits a lot depends on its soil and drainage. See expansive soil by county and why foundations move.
What this means if you own one
Each foundation type fails in its own way. Basements tend to leak at the wall-floor joint and through cracks, so basement waterproofing is the common repair. Crawl spaces hold moisture and can lose support under beams (see crawl space repair). Slabs move with the soil under them (see slab foundation repair).
If you see a wall moving inward, a sudden large crack or floors sagging fast, get a licensed structural engineer to look before any contractor quotes a fix. Our guide on when you need a structural engineer explains how.
Method
Census Bureau Characteristics of New Housing, table "Type of Foundation in New Single-Family Houses Completed" (foundation_cust.xls, sheet SFTotalFoundation), retrieved October 27, 2026. Percentages are the Census figures, computed from unrounded counts. "Slab" includes the Census "slab or other" category.
2023 American Housing Survey national public use file v1.1, household records, retrieved October 27, 2026. We kept occupied units with a reported foundation type (single-family houses and manufactured homes; AHS does not ask it of apartments) and summed the WEIGHT variable by division. Codes come from the AHS 2023 Value Labels file.
Basement combines "under all" and "under part of the house". Manufactured home combines the four mobile-home foundation codes. Other is "foundation set up in some other way" such as stilts or pilings.
Both are sample surveys with sampling error; Census lists relative standard errors in the source file. AHS division figures rest on 270 to 3,600 sample homes each. Regions are Census regions, not states.
How to cite or embed this data
You may reuse the figures and the CSV with attribution (CC BY 4.0). Link back to this page so readers can see the method.
Citation: HyreFoundation Research Desk. (2026). Foundation types by region. HyreFoundation. Data from Census Bureau Characteristics of New Housing and the 2023 American Housing Survey, retrieved October 27, 2026. https://hyrefoundation.com/research/foundation-types-by-region/
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Dataset: /research/new-home-foundation-type-by-region.csv, built from the public source named above. Recompute it from the source if you need a later cut.
Questions
What is the most common foundation type in the U.S.?
Which region builds the most basements?
Why are there so few basements in the South?
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Written and audited by
HyreFoundation Research Desk
Primary-source research and fact checking
We read the model building code, the federal soil and moisture guidance and the insurer position ourselves, and we publish each figure with the document it came from and the date we retrieved it.
Where a number cannot be traced to a primary source, we say so instead of printing it. HyreFoundation does not inspect, engineer or repair foundations. Authorship is organizational: this desk, not a named persona.
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How this desk works
- Primary sources only. Code statements come from the International Residential Code, Chapter 4, as the model code. Soil statements come from USDA and USGS. Insurance statements come from the policy language and the Insurance Information Institute. We open the source rather than cite a blog that cites it.
- The code is a model, and adoption is local. Your jurisdiction adopts an edition and amends it, and foundation chapters are amended more than most because frost depth and soil are local facts. Every code figure says so.
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