How common each type is
According to the National Association of Home Builders’ analysis of the Census Bureau’s Survey of Construction, about 72 percent of new single-family homes started in 2023 were built on slabs, about 17 percent had full or partial basements and about 10 percent had crawl spaces. The slab share has risen steadily from about 46 percent in 2000. Older homes, of course, reflect the building practices of their time and region: basements dominate in the Northeast and Midwest, slabs in Texas and Florida, and crawl spaces across much of the Southeast.
Slab-on-grade
A slab is a concrete floor poured directly on prepared ground, usually thickened at the edges and often reinforced with steel or post-tensioned cables. It is the dominant type in Texas, Florida and much of the South and West.
- Typical problems: settlement or heave on expansive clay, washout under edges, cracks in brick, drywall and tile, sticking doors, plumbing leaks under the slab.
- Typical repairs: piers under settling sections, leak repair, drainage and moisture control.
- Learn more: slab foundation repair, slab leaks, Texas costs.
Crawl space
A crawl space foundation raises the floor a foot or more above the ground on a perimeter wall of block, brick or concrete, often with interior piers or columns under the beams. It is common in the Southeast, Mid-Atlantic and Pacific Northwest.
- Typical problems: sagging or bouncy floors, settled interior supports, moisture and wood rot, bowing perimeter walls on sloped lots.
- Typical repairs: adjustable steel supports, new footings, joist and sill repair, moisture control.
- Learn more: pier & beam and crawl space repair.
Pier-and-beam
Pier-and-beam is a type of raised foundation where the house rests on beams supported by individual piers, sometimes with skirting instead of a continuous wall. It is common in older Texas and Gulf Coast homes and in flood-prone areas.
- Typical problems: settled or leaning piers, crushed shims, sloping floors, damp crawl spaces.
- Typical repairs: re-shimming with steel shims, new piers, beam repair.
- Learn more: pier and beam leveling.
Basement
A basement foundation has full-height walls of poured concrete, concrete block, stone or brick, with a floor several feet below grade. It is typical in the Northeast, Midwest and Mid-Atlantic, where footings must go below the frost line anyway.
- Typical problems: horizontal cracks and bowing walls, water intrusion, settled footings, eroded mortar in old stone walls.
- Typical repairs: wall anchors, braces or carbon-fiber straps, crack injection, underpinning, drainage.
- Learn more: bowing wall repair, stone and brick foundations.
Comparison at a glance
| Type | Where common | Main risks | Repair access |
|---|---|---|---|
| Slab | TX, FL, South, West | Clay movement, washout, slab leaks | From outside or through the slab |
| Crawl space | Southeast, Mid-Atlantic, Northwest | Moisture, sagging floors | From the crawl space |
| Pier-and-beam | Older Texas and Gulf Coast homes | Settled piers, rot | From the crawl space |
| Basement | Northeast, Midwest, Mid-Atlantic | Wall pressure, water, frost | From inside and outside |
Mixed foundations
Many houses combine types: a basement under the original house, a crawl space under an addition and a slab under the garage. Each part moves differently, and cracks often appear where they meet. When you describe a problem to a contractor, mention which part of the house it is in and what foundation is under it.
What each type needs from you
- Slab: even soil moisture, good drainage, prompt leak repair, trees kept at a distance.
- Crawl space: a dry crawl space, working vents or vapor barrier, periodic checks of supports and wood.
- Pier-and-beam: the same as crawl space, plus watching for crushed shims and leaning piers.
- Basement: gutters and grading that keep water away, a working sump pump where needed, monitoring for horizontal cracks and bowing.
Frost depth and why basements are common up north
In cold climates, footings must go below the depth where soil freezes, or frost heave will lift them each winter. Chicago’s building code, for example, requires footings at least three feet six inches below the adjoining ground. Once a builder has to dig that deep, adding a full basement costs relatively little extra, which is one reason basements dominate in the Northeast and Midwest while slabs dominate in warm southern states.
Post-tensioned slabs
Many slab homes in Texas and other clay regions use post-tensioned slabs, with steel cables tightened after the concrete cures. They resist cracking better, but the cables are under high tension. Never cut or drill into a post-tensioned slab without identifying cable locations first; foundation contractors and plumbers use scanning or plans to avoid them.
How to tell what you have
- Stairs down to a finished or unfinished level: basement.
- Vents or an access hatch in the foundation wall outside, and wood floors that sound hollow: crawl space or pier-and-beam.
- Floors at about the same level as the ground outside, no crawl space access: slab.
- Home inspection reports and original plans usually state the foundation type.
Foundations under additions and garages
Garages are usually on their own slab, and many additions sit on a different foundation from the original house: a crawl space addition next to a slab house, a slab sunroom next to a basement, or a porch on shallow piers. Because each part rests on its own footings, they settle at different rates. Separation cracks at the joint, sloping floors where rooms meet and doors that stick between the old and new parts are typical signs. Contractors often support the addition or porch separately, for example with helical piers, rather than treating the whole house.
Questions to ask about your foundation type
- Which parts of the house sit on which foundation type?
- What soil is under the house, and how does it behave in wet and dry seasons?
- Where does water go around each part of the foundation?
- Which repair method fits this foundation type, and why?
What this means for cost
Crawl space and pier-and-beam repairs are often less expensive for minor leveling because the work happens without breaking concrete, but wood damage can raise the price. Slab piering is usually priced per pier. Basement wall stabilization is priced per anchor, brace or strap. See the cost guide and the foundation repair process.