Concrete foundations
Concrete Foundation Cost per Square Foot: Slab, Crawl Space and Basement
Quick reference: the terms that change the price
Four terms explain most of the gap between two quotes for the same job.
Cost per square foot by foundation type
| Type | Cost per sq ft | Typical use |
|---|---|---|
| Monolithic slab | $4 to $14 | Slab-on-grade, garage, simple build |
| Stem wall | $6 to $12 | Raised slab, crawl space |
| Block | $9 to $15 | Crawl space, basement walls |
| Frost-protected slab | $8 to $12 | Cold climates, insulated edges |
| Crawl space | $6 to $18 | Raised floor, access under house |
| Pier and beam | $5 to $16 | Expansive soil, flood zones |
| Alaskan slab | $8 to $14 | Heated slab, cold climates |
| Full basement | $20 to $37 | Extra living space below grade |
The spread is wide because the type changes the excavation, the wall height, the reinforcement and the waterproofing. A basement is not just a taller slab; it is a different build.
Cost by structure type
| Structure | Typical cost range |
|---|---|
| Concrete slab foundation | $5,200 to $21,000 |
| Full basement foundation | $24,000 to $50,000 |
| Garage foundation | $2,000 to $7,000 |
| Mobile home foundation | $3,000 to $36,000 |
| New home foundation | $18,000 to $30,000 |
| Foundation replacement | $25,000 to $115,000 |
A new home foundation is usually priced with the house, but the foundation line is often 8 to 15 percent of the build. A replacement is far more expensive because the house has to be supported while the old foundation is removed.
What drives the price
Size and type. Basements and crawl spaces need taller walls, more excavation and more reinforcement. Soil. Rock, clay or a high water table add excavation and engineering. Frost depth. Deeper footings in cold climates add concrete and labour. Access. A tight lot needs smaller machines and more hand work.
Site work. Clearing, grading, soil tests and dewatering all add cost before the first form is set.
Slab, crawl space or basement
A slab-on-grade is the cheapest foundation and works in mild climates with well-draining soil. A crawl space raises the floor and gives access for plumbing and ductwork, at a higher cost. A basement adds living space but is the most expensive per square foot because of excavation, wall height and waterproofing.
The choice is a design decision as much as a cost one. Cheap soil and a mild climate favour a slab; cold climates and sloped lots often need a basement or crawl space.
Footings and the frost line
Footings spread the house load into the soil and must sit below the frost line in cold climates. Concrete footings average about $6.50 per square foot of footing area, or roughly $150 per cubic yard, and they typically add $5,200 to $15,700 to a foundation project.
A footing that is too shallow heaves in winter and cracks the walls above. Frost depth is set locally; ask the building department.
Permits, soil tests and engineering
Permits for a foundation often run $450 to $2,300 depending on the project size. A soil test is $1,000 to $5,000 and decides the footing design on difficult ground. An architect or engineer may add $2,000 to $10,000 for drawings and structural design.
These lines are easy to forget when comparing quotes, and they are often the difference between a cheap bid and a complete one.
New foundation versus replacement
A new-home foundation is $18,000 to $30,000 for a typical house. Replacing an existing foundation is $25,000 to $115,000 because the structure has to be temporarily supported, the old concrete removed and the new foundation built in stages.
Repair is a third option. Piering is $1,250 to $3,100 per pier and a typical foundation repair is $2,300 to $7,100. A crack repair or drainage fix is cheaper again, but only if the movement is not structural.
Drainage, waterproofing and sealing
Water is the main enemy of a foundation. Sealing a foundation costs about $1,900 to $7,300, a drainage system $1,100 to $6,500, a sump pump $650 to $2,050 and foundation insulation $1 to $5 per square foot.
These are not optional extras on a basement. A dry foundation lasts; a wet one cracks, spalls and grows mould. Budget them with the foundation, not after.
Step by step through a foundation build
1. Site work. Clear, grade and test the soil. 2. Excavate. Dig for the footings and the walls. 3. Footings. Form and pour the footing, then inspect. 4. Walls. Set forms or block, add reinforcement and pour. 5. Waterproof. Apply membrane or coating and drainage. 6. Backfill. Compact in layers. 7. Slab. Pour the floor slab inside the walls.
Each stage needs an inspection in most jurisdictions. Skipping one can mean removing work later.
Frost depth and climate
In cold climates, footings go below the frost line, often 36 to 48 inches or deeper, and the foundation may need insulation and a frost-protected design. In hot, dry climates, the concern shifts to soil shrinkage and movement, which calls for a deeper footing or a pier-and-beam design.
The climate also decides the waterproofing. A basement in a wet climate needs drainage and a membrane; a slab in a dry climate may need none.
A worked example: 1,000 sq ft slab
A 1,000 sq ft monolithic slab at $4 to $14 per square foot is $4,000 to $14,000, before site work, permits and engineering. A stem wall foundation of the same footprint at $6 to $12 is $6,000 to $12,000, and a full basement at $20 to $37 is $20,000 to $37,000 for the same area.
The basement range is where the biggest surprises live. Excavation, wall height, waterproofing and drainage all scale with the design.
What changes the price most
- Foundation type and wall height.
- Soil conditions and water table.
- Frost depth and climate.
- Site access for excavators and trucks.
- Engineering, permits and inspections.
Ask for these lines separately. A low foundation quote with missing site work or engineering is not a comparable price.
Mistakes that cost more later
- Building on fill without testing or compacting.
- Footings above the frost line.
- No drainage around a basement.
- Under-reinforced walls on expansive soil.
- Skipping the inspection before backfilling.
Every one of these is cheaper to fix before the concrete is poured than after the house is on top.
What to ask a foundation contractor
Ask for the foundation type, footing depth, reinforcement, waterproofing and drainage plan, the soil test, the permit and the inspection schedule. Ask what happens if the excavation finds rock or water, and who pays.
Compare quotes on the same design and site work. A foundation quote without a soil test or an engineer is a guess on difficult ground.
Foundation cost and the rest of the build
The foundation is usually 8 to 15 percent of a new home budget, but it is the part that decides how the rest of the house performs. A cheap foundation that moves cracks the walls, sticks the doors and shortens the life of everything above it.
Spend on the site work, the footings and the drainage first. Those are the lines that cannot be upgraded later without major work.
Slab versus crawl space versus basement
| Option | Best for | Cost per sq ft | Trade-off |
|---|---|---|---|
| Slab-on-grade | Mild climate, good soil | $4 to $14 | Cheapest, no under-floor access |
| Crawl space | Cold or wet climates | $6 to $18 | Access for plumbing, more cost |
| Full basement | Extra living space | $20 to $37 | Most expensive, most space |
| Pier and beam | Expansive soil, flood zones | $5 to $16 | Repairable, better for problem soil |
The cheapest option is not always the best value. A crawl space costs more than a slab but avoids freezing pipes and gives access for repairs that a slab makes expensive.
How foundation costs vary by region
Labour, soil, frost depth and local code move the price. Cold states pay more for deeper footings and insulation; wet states pay more for drainage and waterproofing; rocky ground adds excavation; and a busy market adds labour. The per-square-foot ranges are national benchmarks, not local quotes.
Ask for two local quotes on the same design. The site work is often the largest difference between two bids for the same house.
Repair or replace a foundation?
Repair when the movement is local and the structure is sound: crack injection, drainage, piers under one corner. Replace when the foundation has failed broadly, the house needs to be lifted, or the repair cost approaches a large share of a replacement.
An engineer report is the cheapest way to decide. It costs a fraction of either repair and it protects you from buying the wrong one.
What a foundation quote should include
A complete quote names the foundation type, footing size and depth, reinforcement, waterproofing, drainage, slab, permits, soil test, engineering and site work. It should also say who handles rock, water or unsuitable soil found during excavation.
If a quote is one line, it is a placeholder. Compare itemised scopes before comparing totals.
Foundation insulation and energy
Foundation insulation costs $1 to $5 per square foot and reduces heat loss through the slab or walls. In cold climates, a frost-protected shallow foundation with insulated edges can be cheaper than digging deep footings, and it keeps the slab warmer.
Insulation is one of the few foundation upgrades that pays back every winter. Ask whether it is included or priced separately.
Budgeting the site work
Excavation and grading are often priced at $2 to $10 per square foot and can be the largest mover when the site is difficult. Rock, a high water table, a tight lot or a slope all add machine time and hauling.
Get a site visit before the quote. A foundation priced from a drawing alone is a guess on an unknown site.
Foundation cost and resale
A sound foundation is one of the first things a buyer inspects and one of the most expensive things to fix. A documented new or repaired foundation supports the asking price, while an unexplained crack can delay a sale.
Keep the engineer report, permits and inspection records with the house documents. They are the proof that the work was done correctly and the first thing a future buyer or inspector will ask to see.
Cost by house size
| House size | Slab ($4 to $14) | Crawl space ($6 to $18) | Basement ($20 to $37) |
|---|---|---|---|
| 1,000 sq ft | $4,000 to $14,000 | $6,000 to $18,000 | $20,000 to $37,000 |
| 1,500 sq ft | $6,000 to $21,000 | $9,000 to $27,000 | $30,000 to $55,500 |
| 2,000 sq ft | $8,000 to $28,000 | $12,000 to $36,000 | $40,000 to $74,000 |
| 2,500 sq ft | $10,000 to $35,000 | $15,000 to $45,000 | $50,000 to $92,500 |
These are foundation-only ranges. Site work, permits, engineering and drainage are added on top, and they are often 10 to 25 percent of the total.
How long a concrete foundation lasts
A well-built concrete foundation can last a century or more. The variables are the soil, the drainage, the concrete quality and the waterproofing. Foundations fail early when water is not moved away, when the footing is too shallow or when the soil moves seasonally.
Maintenance is mostly water management: gutters, grading, downspouts and drainage. A dry foundation is a long-lived foundation.
Signs you need a foundation inspection
Call an engineer if you see wide or widening cracks, doors that stick, floors that slope, gaps at windows, or a crack with one side pushed out. A hairline shrinkage crack is usually cosmetic; movement is not.
An inspection is cheaper than a repair and much cheaper than a missed structural problem. Photograph the crack with a ruler and note when it appeared.
Common foundation problems and costs
Hairline shrinkage cracks are cosmetic and can be sealed for a few hundred dollars. A leaking crack is injected for about $350 to $900. A settled corner is piering at $1,250 to $3,100 per pier, and a bowing wall can need carbon fibre straps or anchors. A wet basement is a drainage and waterproofing job, not a concrete job.
The repair cost depends on what the crack is telling you. A structural engineer report is the cheapest way to tell the difference.
Foundation cost and home value
A sound foundation supports the asking price; a failing one can delay or kill a sale. Buyers and inspectors look for cracks, slopes and water stains, and an undocumented repair raises questions. Keep the engineer report, permits and inspection records.
A repaired foundation with paperwork is easier to sell than an unexplained crack. The cost of the repair is often smaller than the discount a buyer will ask for, and the documentation answers the question before it is asked.
How to choose a foundation type
Start with the soil, the climate and the lot. A well-draining site in a mild climate can use a slab; a cold climate needs footings below frost depth and may need a crawl space or basement; expansive clay or a flood zone often calls for pier and beam. The house design and the budget then narrow the choice.
Ask an engineer or a local foundation contractor which type is normal for the area. Building against local practice usually costs more and performs worse, and it can make future repairs harder to price because local crews are set up for the standard design.
Concrete foundation cost calculator
Enter the footprint area and pick a foundation type to see the range.
Estimates, not quotes. Ranges from our October 2026 research. See the price index.
| Line | What it covers | Typical share |
|---|---|---|
| Excavation and site work | Dig, grade, haul spoil | $2 to $10 /sq ft |
| Footings | Form, concrete, reinforcement | $5,200 to $15,700 |
| Foundation walls | Concrete or block, reinforcement | $6 to $20 /sq ft |
| Waterproofing and drainage | Membrane, drain tile, gravel | $1,100 to $7,300 |
| Slab | Interior floor slab | $4 to $8 /sq ft |
| Permits and engineering | Permit, soil test, drawings | $1,450 to $12,300 |
What this guide does not cover
Some jobs depend on things a national range cannot see. These are the ones where you need a local quote or an engineer.
- Engineered foundation design for unusual soil or loads.
- Full foundation replacement, priced separately.
- Drainage systems and dewatering.
- Hazardous materials or contaminated soil.
- Permits and inspections that vary by city.
Concrete foundations prices and contractors by state
Ranges here are national with a checked month. Local prices move with labour rates, climate and permit rules, so check your state before comparing bids.
Run the full calculator for your own dimensions: open the calculator →
Questions about concrete foundation cost per square foot
How much does a concrete foundation cost?
About $5 to $37 per sq ft depending on type, with a typical project around $9,100.
How much per square foot for a slab foundation?
About $4 to $14 per sq ft for a monolithic slab.
How much for a basement foundation?
About $20 to $37 per sq ft, or $24,000 to $50,000 for a typical full basement.
How much for a crawl space foundation?
About $6 to $18 per sq ft depending on height, insulation and drainage.
How much is a new home foundation?
Usually $18,000 to $30,000 for a typical house.
How much is foundation replacement?
About $25,000 to $115,000, because the house must be supported during the work.
How much is foundation repair?
A typical repair is $2,300 to $7,100; piering is $1,250 to $3,100 per pier.
Do I need a soil test?
On difficult or unknown ground, yes. It is $1,000 to $5,000 and decides the footing design.
How deep should footings be?
Below the frost line, often 36 to 48 inches in cold climates. Check local code.
How much does foundation waterproofing cost?
About $1,900 to $7,300 for sealing, or $1,100 to $6,500 for a drainage system.
Do I need a permit for a foundation?
Almost always. Permits are typically $450 to $2,300.
How long does a foundation take?
A simple slab can take a few days; a basement with waterproofing and inspections takes weeks.
Can I build on expansive clay?
Only with the right design, often a pier-and-beam or a deepened footing. Get an engineer.
Why is a basement so much more expensive?
Excavation, taller walls, waterproofing, drainage and inspections all add cost.
How do I compare foundation quotes?
Match type, footing depth, soil test, waterproofing, drainage, permits and site work, then compare totals.
Foundation ranges from published national foundation cost research (Bob Vila foundation cost guide: $5–$37/sq ft by type, average $9,100, new-home foundation $18,000–$30,000) cross-checked against the LocalServiceHQ October 2026 index for piering and foundation repair. Footing and frost guidance follows common building practice; confirm local code.
Estimates, not quotes. National ranges checked October 2026; local quotes vary by city, access and finish. · What changed on this page · Report a correction