Written by
Tom Grupa
Foundation Cost
A typical 1,200-square-foot house foundation costs$6,900 to $16,200for a concrete slab, or about$40,000for a full unfinished basem*nt. A floating slab for a mobile home runs$4,600 to $14,000, while a standard 24’ x 24’, 2-car garage foundation costs$3,100 to $4,800.
National Average Cost | $9,300 |
Minimum Cost | $4,600 |
Maximum Cost | $26,750 |
Average Range | $5,100 to $19,400 |
The main types of foundations are slab-on-grade, which is the most common and least expensive; a crawl space foundation that has short walls, pier and beam, or a full basem*nt foundation with 8’-10’ walls for living or storage.
Foundation Type | Average Cost Per Square Foot | Average Total Cost |
---|---|---|
Monolithic Concrete Slab | $5 | $4,600 – $20,000 |
Stem Wall Concrete Slab | $6 | $7,000 – $20,000 |
Pier and Beam | $9 | $7,200 – $13,500 |
Crawl Space | $13 | $10,300 – $19,400 |
Basem*nt | $33 | $26,800 – $50,300 |
A correctly installed foundation holds the weight and load of the house in place, insulates against the cold, keeps moisture out, and resists the movement of the surrounding earth.
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Foundation Cost Calculator
Foundation installation prices include the cost of the excavation, grading, and footings. The foundation type and depth dictate the labor and materials cost. Calculating your house foundation cost depends on:
Site and ground conditions, including local flooding, earthquake, frost heave, wind, and termite prospects
Design factors imposed by the buyer, lender, and local building codes
Construction practices
Square Feet | Concrete Slab | Pier and Beam | Basem*nt (Unfinished) | Crawl Space | Raft |
---|---|---|---|---|---|
800 | $4,600 – $10,800 | $7,200 | $26,800 | $10,300 | $6,000 |
1,000 | $5,800 – $13,500 | $9,000 | $33,500 | $12,900 | $7,500 |
1,200 | $6,900 – $16,200 | $10,800 | $40,200 | $14,500 | $9,000 |
1,500 | $8,700 – $20,300 | $13,500 | $50,300 | $19,400 | $7,500 |
2,400 | $13,900 – $32,400 | $21,600 | $80,500 | $31,000 | $12,000 |
Foundation Cost Per Square Foot
A foundation costs$5 to $33 per square footdepending on the type. A poured concrete slab costs between$5 and $14 per square foot, while an unfinished basem*nt foundation averages$33 per square foot.
House Foundation Types | Cost Per Square Foot |
---|---|
Monolithic Concrete Slab | $5 – $14 |
Stem Wall Concrete Slab | $5 – $6 |
Pier and Beam | $7 – $11 |
Crawl Space | $7 – $14 |
Raft | $5 – $10 |
Basem*nt (unfinished) | $33 |
Concrete Slab Foundation Cost
Aconcrete slab foundation costs$5.75 to $13.50 per square foot, with most homeowners spending $5,800 to $20,300. The total cost depends on the size, condition of the soil, location, and whether it's a monolithic slab, stem wall slab, or a raft foundation.
The average cost to build a 1,350-square-foot concrete slab foundation for a one-story home is$8,600. If extra footings are required, add$6.50 per square footto the cost.
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Concrete slabs are used as foundations for houses at an average thickness of 6", but also poured 4” to 8” thick for mobile homes, garages, workshops, driveways, and patios.
Pier and Beam Foundation Cost
Pier and beam foundations cost $7 to $11 per square foot, averaging$7,200 to $13,500total. The more uniform the shape of the house is, the lower the cost. Costs increase when different sections of the house start projecting off from a central shape, with sloping in the site.
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Piers – Concrete piers are drilled about 12" below the frost line and poured first. Piers are spaced 5' to 10' apart depending on the condition of the soil, the design of the home, and the weight load.
Joists & Grade Beams – Wood or concrete joists are run horizontally every 12' along the top of the piers. Some companies use steel jack stands or masonry blocks, or even hardwood posts, rather than concrete. The foundation (whether wood or concrete) rests on the beams.
Basem*nt Foundation Cost
An unfinished basem*nt foundation costs$33 per square footinstalled on average, while thecost to finish a basem*ntadds$32 and $47 per square foot. Most homeowners spend$26,000 to $80,000to build a full basem*nt foundation with adequate moisture prevention and drainage.
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A basem*nt foundation may be built entirely below ground or partially above it.
Crawl Space Foundation Cost
A crawl space foundation costs$7 to $14 per square foot, or $10,300 to $19,400total. A crawl space foundation costs more than a pier and beam home due to the additional excavation costs and concrete perimeter walls, but crawl spaces protect against water damage.
Framing a house on a crawl space foundation costs30% morethan one over slab-on-grade.
Crawl spaces foundations create an 18" to 24" space under the home that may be ventilated or completely closed off.
Pros | Cons |
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Many contractors recommend building a basem*nt over a crawl space due to the return on investment (ROI) on extra living or storage space.
Concrete Foundation Cost
The average concrete foundation costs$5,100 to $15,400, or $6.80 to $10.30 per square footfor materials and installation. Your final cost will depend on the size and thickness of the slab, and if you add any special reinforcement such as wire mesh or rebar.
This is the easiest and cheapest foundation for a home. One solid slab is poured for the entire house, and it doesn’t require deep excavation.
Square Feet | Pouring Labor | Materials (6" Thick) | Average Total |
---|---|---|---|
400 | $1,000 | $1,500 | $2,500 |
500 | $1,300 | $1,900 | $3,200 |
576 | $1,500 | $2,200 | $3,700 |
600 | $1,600 | $2,300 | $3,900 |
800 | $2,100 | $3,000 | $5,100 |
1,000 | $2,600 | $3,800 | $6,400 |
1,200 | $3,100 | $4,600 | $7,700 |
1,500 | $3,900 | $5,700 | $9,600 |
2,400 | $6,200 | $9,100 | $15,300 |
Monolithic Slab Foundation Cost
A monolithic slab foundation costs$5 to $14 per square footinstalled. A monolithic slab is a concrete slab that is poured once at least ½ a foot above the ground and is thicker around its perimeter. Within this category are one-way beam and two-way beam slabs.
Square Feet | One-Way Beam | Two-Way Beam |
---|---|---|
800 | $7,800 | $10,800 |
1,000 | $9,800 | $13,500 |
1,200 | $11,800 | $16,200 |
1,500 | $14,700 | $20,300 |
2,400 | $23,500 | $32,400 |
Monolithic one-way beams cost $9.80 per square foot on average. This type of foundation pours the beams (or footers) at the same time as the slab. A one-way beam supports the foundation on two edges.
Monolithic two-way beams cost about $13.52 per square foot. A two-way beam supports all four foundation edges at the same time, providing a more stable base.
Stem Wall Foundation Cost
A stem wall foundation costs $50 per linear footinstalled, or $7,000 to $20,000total. A 37’ x 8’ tall wall costs about$1,900. The average cost to build a 1,350-square-foot stem wall foundation is$7,600.
A stem wall foundation works well when building on a slope, as different sections can be built to different heights. The slab can be elevated to accommodate septic systems based on gravity flow.
Stem walls add stability to homes and buildings in areas where earthquakes may happen, or soil may become unstable.
Average Cost of a Raft Foundation
Raft foundations cost $5 to $10 per square foot. The cost to build a 1,350-square-foot raft foundation is about$10,100. Reinforcing the concrete with rebar costs an additional$1 to $2 per square foot.
Mat or raft foundations are used where there are poor ground conditions, such as soil that is unable to bear any loads. The concrete slab rests on steel-reinforced soil, columns, or walls. The load or the weight of the house is stabilized through the raft foundation and dispersed to the earth.
Labor Cost to Pour a Concrete Foundation
The labor cost to pour concrete is$2.60 per square foot, while the cost of concrete alone is$3.81 per square foot. The total cost to pour a concrete foundationis $6.41 per square footon average. Concrete contractors charge$50 to 150 per hourwith additional concrete delivery fees of$60+.
To pour a 1,200-square-foot foundation,$3,100would be attributed to labor and$4,600inconcrete costs. Pouring a foundation typically takes a full 8 hours with a 3-person crew.
Concrete slab foundations for homes should be 6” thick with 3,000 PSI concrete. After the lot is graded with sand and crushed gravel, and footings are poured, one solid slab is poured for the entire house, usually inside a wooden frame filled with rebar—iron mesh—to strengthen the concrete slab and prevent cracking.
Basem*nt Foundation Cost Calculator
The cost to build a basem*nt is$26,000 to $80,000. The cost to pour a basem*nt averages$33 per square foot, lower than thecost of adding a roomat$90 to $200 per square foot. Basem*nt installation cost depends on excavation, grading, materials, labor, size, style, and finishing.
Square Feet | Excavation | Flooring | Stem Walls | Total (Unfinished) |
---|---|---|---|---|
800 | $12,000 | $4,600 | $10,200 | $26,800 |
1,000 | $15,000 | $5,800 | $12,800 | $33,600 |
1,200 | $18,000 | $6,900 | $15,300 | $40,200 |
1,500 | $22,500 | $8,700 | $19,100 | $50,300 |
2,400 | $36,000 | $13,900 | $30,600 | $80,500 |
Once excavation work is complete, a typical unfinished basem*nt is built in three steps – footings, walls, floor.
The footings are poured and the ground is graded.
A drainage system is set up around the exterior of the footings to carry water away from the foundation.
The walls are poured into grooves cut into the footings, so they are fastened to the footings.
The forms are then removed, and the dirt is backfilled.
A vapor barrier is laid.
The concrete floor is poured last.
The exterior walls are waterproofed.
Precast concrete steps are usually dropped in place with a crane.
Item | Percent of Budget | Cost Per Square Foot |
---|---|---|
Excavation (10’ – 12’ depth) | 45% | $10 – $20 |
Foundation Floor | 17% | $5.75 |
Stem Walls | 38% | $12.75 |
Basem*nt Excavation Cost
Basem*nt excavation costs for a foundation are $2.50 to $15.00 per cubic yard, depending on the size and depth. Prices can vary significantly based on the condition of the soil (light, wet, or rock), and the type of equipment used.
Soil Condition | Cost Per Cubic Yard |
---|---|
Light soil | $2.50 – $6.00 |
Average soil | $6.00 – $10.00 |
Heavy/wet soil or loose rock | $10.00 – $15.00 |
Jackhammered rock | $50.00 – $200.00 |
Depth & Difficulty | Cost Per Square Foot |
---|---|
12’ – 18’ Depth | $10 – $12 |
Deeper Footings | $12 – $15 |
Difficult Soils | $15 – $20 |
A basem*nt is one of the most expensive foundations to build but also the most versatile; giving additional living and storage space without the expense of a complete add-on to the home.
Building a basem*nt as part of new home construction can greatly increase the value of your home.
Building a Basem*nt for a New Home
Basem*nt installation for new construction costs$26,000 to $50,000. Excavating at least eight feet deep and then grading the land is the most significant expense followed by materials, drainage systems, sealing, and waterproofing.
There are three main types of basem*nts to choose from based on your specific location, soil, and groundwater conditions. Standard full basem*nts typically have 8'-10' walls and can only be accessed from inside the house.
Standard Full Basem*nt
Walk-out Basem*nt
Daylight Basem*nt
Daylight or Walkout Basem*nt Cost
A typical walkout basem*nt costs$47,000 to $100,500. A walkout basem*nt costs about $20,000 more than a regular full basem*nt and requires extra excavation and grading.
If your home is built on a hillside, creating a daylight basem*nt allows for full-size doors and windows that let natural light into the area through exposed walls. The cost to build a daylight basem*nt is higher than a full basem*nt, due to:
More extensive underground footings
Higher foundation walls on the low side
Higher construction costs from building on a slope
Additional excavation
More site preparation on hillsides because of the complexity of working on them and getting materials to and from the site
Breaking the basem*nt slab to reach the sewer line
Finished or Unfinished Basem*nt?
Building a finished basem*nt costs an additional$22,000 to $46,000to make it into a livable space with rooms. If you plan to finish your basem*nt, there are a few things you can do now, at the foundation stage.
Dig deeper and get higher basem*nt ceilings than the typical 8 feet in height to make room for the pipes and ductwork. Ideally, excavate to give your basem*nt 9’ or 10’ ceilings.
With higher walls comes the need for thicker walls, as they need to be strong enough to safely support both the lateral load and the load above the house. Upgrading to 3,500 PSI concrete is recommended for this purpose.
Prevent potential moisture and soil gas problems with vapor barriers and adequate ventilation.
Cost to Add a Basem*nt to an Existing House
The averagecost to raise a house to add a basem*nt is$40,000 to $50,000, or about$40 to $100 per square foot. Almost 20% of that amount goes toward raising the house. A structural engineer determines if the home is structurally sound enough to lift above the foundation.
There are risks in raising a house and repairs that should be factored into the total cost. Aroom additionmay be more cost-effective and easier on your home than adding a basem*nt.
Square Feet | House Raising | Foundation | Total |
---|---|---|---|
800 | $8,000 – $14,400 | $26,800 | $37,800 |
1,000 | $10,000 – $18,000 | $33,500 | $47,500 |
1,200 | $12,000 – $21,600 | $40,200 | $57,000 |
1,500 | $15,000 – $27,000 | $50,300 | $71,300 |
2,400 | $24,000 – $43,200 | $80,500 | $147,700 |
Level | Cost Per Square Foot | Description |
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Level 1 | $10 – $18 | House elevation service only. It does not include installation of a new foundation system, reconnecting plumbing or electrical systems, or other finishing tasks. |
Level 2 | $30 – $60 | House elevation and installation of the new foundation system. |
Level 3 | $60 – $90 | House elevation and all elements of the architectural, engineering, and structural design tasks. |
Basem*nt Extension Foundations Cost
When building an extension, you’ll find that you might have to dig the foundation deeper than the existing foundation to match updated building codes. If your house is old, you might have to underpin the existing foundation to avoid possible structural damage from attaching the extension to it.
Cost To Dig A Basem*nt
The cost to dig a basem*nt for new construction is$12,000 to $36,000. Basem*nt excavation costs$10 to $20 per square footand takes 2 to 4 weeks to dig out and build. Digging a basem*nt under an existing house averages$47 per square footbecause the house must be raised first.
An engineer’s survey is required before digging to make sure there are no underground utilities in place.
Many houses built on a slab foundation have their plumbing under the slab, which has to be rerouted and pushes the price up.
If grading is required to direct water away from the house, finegrading and leveling land costs$0.40 to $2.00 per square foot.Installing a yard drainage system costs$1,000 to $4,000.
Cost To Pour A Basem*nt
The cost to pour a basem*nt foundation and walls is$14,800 to $44,500or an average of$18.50 per square foot. The concrete and labor cost to pour a basem*nt depends mostly on how deep the excavation work needs to be and the condition of the soil.
A monolithic slab will cost more to pour than a regular slab because the footings have to be set in place before the pour.
Square Feet | Stem Walls | Concrete Floor | Total |
---|---|---|---|
800 | $10,200 | $4,600 | $14,800 |
1,000 | $12,800 | $5,800 | $18,600 |
1,200 | $15,300 | $6,900 | $22,200 |
1,500 | $19,100 | $8,700 | $27,800 |
2,400 | $30,600 | $13,900 | $44,500 |
Cost of Poured Concrete Foundation Walls
Most basem*nt and concrete foundation walls are a minimum of 8” thick. An 8-inch poured concrete wall costs$12.75 per square foot or$1,200 poured on average.
Ready-mix concrete costs$120 to $150 per cubic yard, and an 8-inch thick basem*nt wall measuring 12’ x 8’ will use 2.37 cubic yards of concrete, so concrete alone costs$280 to $350 per average wall.
Poured concrete foundation walls are preferable to block foundations because they are stronger, hold heat better, are more fire-resistant, and are more watertight.
Although cracks can happen in any piece of concrete, a poured concrete wall is more waterproof than a block foundation, which has many seams.
Concrete foundation walls must cure on-site, so water or freezing temperatures might affect the cure.
Walls taller than 8 feet should be 10 inches thick rather than the standard 8 inches for shorter walls—to withstand the pressure of lateral soil movement.
Block Foundation Cost
Ablock foundation costs$7,950 to $41,600, priced at$12 to $18 per square foot. Materials alone cost$7 to $9 per square footfor walls using 8” x 16” blocks, without the footings. A concrete block wall has an exterior concrete form with reinforcing steel and is filled with concrete or cement grout.
A block foundation costs more than a poured foundation because of the skilled labor needed to lay the blocks
Block foundations can hold up more compression weight than poured walls, but blocks incur a big leak risk due to all the seams between the blocks and mortar.
Item | Average Cost |
---|---|
Building Permit | $500 – $1,500 |
Excavation and Grading | $1,150 – $15,000 |
Forms and Finishing | $1,600 – $5,000 |
Concrete Reinforcement | $150 – $500 |
Concrete | $2,500 – $12,000 |
Waterproofing and Sealing | $1,900 – $6,300 |
Inspection | $150 – $1,300 |
Total | $7,950 – $41,600 |
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Best Foundation For A House
The best foundation for a house depends on the soil, groundwater conditions, and frost line of the ground in the area—the depth to which the groundwater in the soil freezes. The foundation has to go below the frost line because freezing water expands 9% and disturbs the foundation’s structural integrity.
To choose the best type of foundation and to calculate the house foundation cost, you’ll need to know:
The condition of the soil on the lot
How much grading and excavation work will be required
How deep the footings need to go and how many are required
If there are any flooding or moisture concerns
How deep the foundation needs to be to go past the frost line
Shallow vs. Deep Foundations
Deep foundations cost more than shallow foundations and require additional excavation, materials, and labor.
Shallow Foundation
A shallow foundation, slab-on-grade, or floating slab is a concrete slab that is formed from a mold set into the ground below the frost line.
Shallow foundations transfer the building loads to the earth through a slab of concrete.
This type of foundation is often used in warmer climates where ground freezing and thawing are less of an issue.
Deep Foundation
A deep foundation is typically used in poor soil conditions, unlevel ground, or if the structure needs to be raised to prevent flooding.
Deep foundations are constructed from steel, wood, or reinforced concrete, and require the assistance of a structural engineer.
Cost To Rebuild or Replace Foundation
For concrete slabs, the cost to rebuild a foundation is$16 per square foot, with the average homeowner spending$20,000 to $40,000on foundation replacement.Foundation repairs costfrom$250to repair minor cracks up to$20,000for major repairs that require hydraulic piers.
The cost of demolition of the old slab foundation runs about$21 per cubic foot, and a new typical 6" thick concrete slab costs$6.80 to $10.30 per square foot.
Square Feet | Demolition | Poured Concrete and Labor | Total |
---|---|---|---|
800 | $8,400 | $4,600 | $13,000 |
1,000 | $10,500 | $5,800 | $16,300 |
1,200 | $12,600 | $6,900 | $19,500 |
1,500 | $15,800 | $8,700 | $24,500 |
2,400 | $25,300 | $13,900 | $39,200 |
Foundation Replacement Cost Factors
Structural Report – A structural engineer charges $100 to $220 per hour. An engineer’s report may be required before you can begin work. The engineer will give an unbiased recommendation on the best kind of foundation replacement for the house which could end up saving you money.
Raising the House – The cost to lift a house and replace the foundation depends on the size of the house and the number of stories. Expect to spend $10,000 to $40,000 to raise a house to replace the foundation with a concrete slab or piers.
Excavation – The cost of excavation is $10 to $20 per square foot or $2.50 to $2.70 per cubic foot. Excavation may be required if the previous space for the old foundation, once demolished, isn’t deep enough. The soil will need to be moved away from the old foundation to build new forms for the new foundation.
Rebuilding – The cost of the new foundation is the same as if you were doing new construction. A simple slab concrete foundation costs $6.40 per square foot and will be the most economical decision after paying for the house to be raised.
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Replacing Different Foundation Types
Crawl Space – Remove and replace any wet wood, insulation, or posts. Install a new moisture barrier sheet to keep it dry.
Crawl space repair and cleaning costs $1,500 to $15,000 for mold removal, ventilating, insulating, and reinforcing or replacing the foundation joists.
Crawl space encapsulation costs $3 to $7 per square foot to prevent future moisture issues.
Pier and Beam – Replacing or stabilizing piers under your house due to shifting soil or the need for a stronger foundation, costs from $950 to $1,600 per steel pier or $1,400 to $2,100 per helical pier. A high-end repair of piers and beams will cost about $10 per square foot.
Concrete Slab – A typical reinforced 6” slab concrete foundation costs $6.40 to $10.30 per square foot. If you need to correct drainage problems at the same time (which can often be the cause of cracks), it can cost $1,100 to $5,500.
Average Mobile Home Foundation Cost
A permanent foundation for a mobile home costs between$3,000 to $36,000depending on the type. A floating slab costs$4,600 to $14,000, while a crawl space runs$4,900 to $16,800. Installing a basem*nt foundation under your mobile home costs$23,000 to $36,000.
Foundation Type | Average Cost |
---|---|
Pier and Beam | $3,000 – $8,000 |
Floating Slab | $4,600 – $14,000 |
Crawl Space | $4,900 – $16,800 |
Basem*nt | $23,000 – $36,000 |
Pier and Beam – A pier and beam foundation for manufactured and mobile homes is common. They are secured to the sill of the foundation with a nailing strip. Ground anchors attached to the home with steel straps can help resist wind uplift, and they can be used in conjunction with stabilizer plates.
Floating Slab – A slab foundation for a mobile home is one of the best options for colder climates. They don’t need to be measured precisely to the base of the house. Slab foundations need to be insulated around the perimeter to keep the ground under the home warmer, or they tend to shift with soil movement during frost heave. Mobile homes must be anchored to the foundation with anchors embedded in the concrete.
Crawl Space – One of the difficulties with moving a manufactured home onto a crawl space foundation is that the foundation has to match the exact dimensions of the house. If the foundation site isn’t accessible from the street to place the home with rollers, a crane will be required, directing the chassis beams onto the installed concrete, wood, or steel piers.
Basem*nt – Installing a manufactured home onto a basem*nt foundation is difficult. The outside walls of the foundation must be the exact length and width of the mobile home, and not many contractors have enough experience to do the job correctly. Part of the difficulty is attaching the shearwalls and chassis properly to the foundation system, and all the rough-ins to go under the floor must be designed before the house goes in. Foundation bolts are usually used to secure the home.
It’s always best to check with the manufacturer of the home for their recommendation of the best type of foundation to go with the home you purchased.
Garage Foundation Cost
A 24’ x 24’, 2-cargarage foundation costs$3,100 to $4,800, while a 16’ x 24’, 1-car slab costs$2,000 to $3,200installed. Prices range from$5.30 to $8.30 per square footfor a 4” reinforced concrete slab, and$6.80 to $10.30 per square footfor a 6” slab installed.
Size (4” Deep) | Square Feet | Average Cost |
---|---|---|
16’ x 24’ | 384 | $2,000 – $3,200 |
20’ x 20’ | 400 | $2,100 – $3,300 |
24’ x 24’ | 576 | $3,100 – $4,800 |
20’ x 30’ | 600 | $3,200 – $5,000 |
36’ x 24’ | 864 | $4,600 – $7,200 |
You may need to have the land graded which carries a$3,000minimum job charge. You’ll also need excavation done at$2.50 to $2.70 per cubic foot, which costs$480 to $520for a 24' x 24' garage slab, but this should be included in the quote from your contractor.
If you’rebuilding a garageslab right beside the home and sharing a wall, you could run into a lot of structural damage if the new slab starts to shift. An engineer can design it with expansion joints to offset this possibility.
Additional Foundation Estimates
Below are average overall cost estimates by structure.
Structure | Average Cost |
---|---|
Concrete Slab | $5,000 – $15,000 |
Full Basem*nt | $26,000 – $80,000 |
Garage | $2,000 – $5,000 |
Mobile Home | $3,000 – $14,000 |
Cement Foundation Cost Factors
Cost factors that increase or decrease the cement foundation cost are:
Required prep work on the lot
Grading
Concrete thickness
Moisture barrier
Forms and reinforcements used
Delivery and pouring or pumping costs
Finishing methods
Concrete Footing Cost
Concrete footings cost$6.50 per square footor$150 per cubic yard. Footings add$5,200 to $15,700to the cost of the foundation, with prices growing as the footings go deeper and wider. The estimated cost for footings and a foundation is usually quoted together by contractors.
Footings must extend below the surface of the earth, deep enough to get past the unstable soil that exists in many locations.
Footings are typically poured separately from the slab, except in the case of monolithic slabs.
Cost of Pilings for Foundations
The cost of pilings for securing your foundation costs$15,000 minimum, plus site testing, which could add$20,800. It’s expensive because of the steps involved—soil study, excavation, concrete, capping beams, rebar, design, and project management—possibly more expensive than a solid column base.
The cost of driving in the pilings can vary based on the materials used.
Type | Minimum Cost |
---|---|
Wood – Treated or Untreated | $20,000 |
Steel Pipe Piling | $20,000 |
Prestressed Concrete Piling | $28,000 |
Steel HP-share Piling | $20,000 |
Concrete-filled Steel Piling | $15,000 |
In the case of unstable soil, pilings are used in conjunction with piers—they go even deeper beneath the piers to provide additional security and spread the weight load of the building. Sometimes you can dig out tunnels for the pilings around piers with an auger yourself, saving the excavation costs.
Pilings are sometimes necessary when the soil is soft, and when a solid base is not available at the proper depth.
Pilings may be required when constructing a building near the seashore or riverbed.
Planning and Permit Prices
Some cities charge a$30 to $150 flat feefor your permit, while in other cities, building permits are generally figured as a percentage of the total job averaging$500 to $1,500. Your contractor should take care of the permits.
Building a foundation will always require a permit, but if you’re adding an extension or building a house, the permit for the entire project will cover the foundation.
Total Price of Job | Price of Building Permit |
---|---|
$500 – $2,000 | $80 |
$2,000 – $25,000 | $140 |
$25,000 – $50,000 | $800 |
$50,000 – $100,000 | $1,300 |
Foundation Inspections
Foundation inspections cost about$145 an hour, with most homeowners spending$150 to $1,300total. Inspections verify that the new foundation meets all code requirements and will support the weight of your home.
The inspections will take place before you pour concrete and after the work is done.
The pre-work inspection should take about 90 minutes, and you will receive a written report which will outline any changes that must take place before pouring.
A pre-construction geotechnical soil test costs $1,000 to $5,000 to determine if the ground is stable enough to support a foundation.
Drainage and Radiant Heat
When installing a new concrete foundation, there are things you can do now that will be more difficult, if not impossible, to do after the foundation is poured.
Radiant heat adds$3 per square footwith most homeowners paying$4,800 to $10,000. Drainage systems such asFrench drains and sump pumps cost$2,500 to $12,000to install.
System | Average Cost |
---|---|
French Drain System | $6,000 – $12,000 |
Sump Pump | $500 – $1,200 |
Sump Pump System | $2,500 – $5,500 |
Radiant Heat | $16 – $26 per SF |
French drains are installed around the foundation to drain water away from the house. The drained water is often directed to the sump pump, which forces the water away from the house. It’s easy to install while the house is under construction, but much more expensive to connect to an existing home.
If your basem*nt might be prone to water problems, a sump pump can help alleviate that.
Radiant heat is a luxury item where all pipes need to be laid under the foundation, and the concrete is poured over them. You cannot install radiant heat under a concrete foundation at a later date. If you miss the boat, another option is to place it under your flooring.
To provide better protection against moisture issues, install a gutter system, and invest a lot in the grading of the land before work begins.
Foundation Insulation
Foundation installation costs about$2,000on average. Many homeowners install skirting and vents around the crawl space or pier and beam foundation to allow for proper airflow, prevent moisture, and keep critters out. Otherwise, they install a vapor/moisture barrier and dehumidifier.
Homeowners who want more insulation under the floor will add spray foam, foam board, or batts between or across the bottom of the joists.
Cost To Seal Concrete
The cost to seal a concrete foundation professionally with an acrylic spray-on cure and seal will cost about$0.50 per square foot. Contractors typically charge a minimum fee of$100 to $200regardless of project size and add 50% more to your total cost if two coats are required.
DIY costs range from$0.20 to $0.75 per square foot. Some decorative sealers will need to be reapplied every few years, while a penetrating sealer will need to be applied every 5 to 10 years.
The main reason to seal your concrete is to keep water from eroding it and causing cracking. The cracks enlarge, and the water carries damaging salts and chlorides to the metal reinforcements damaging them as well. Applying a sealer will densify the concrete, giving it years of additional, crack-free life.
Cost to Lay A Precast Foundation
The cost to lay a precast foundation is$11 to $13 per square footwith more than 50% of the costs coming from labor. Prefab concrete slabs are poured and cured offsite then delivered to your job site and laid down over a prepared area.
Precast foundations are used for a shed or garage, but they are not strong enough for a home foundation.
The most common use for pre-poured slabs is in the form of pavers installed in patios, driveways, and courtyards.
Hiring A Foundation Contractor
Before hiring a concrete contractor, be sure to get at least three formal bids to compare and verify the following:
Get at least three formal bids to compare.
Confirm their experience with pouring foundations.
Confirm they are licensed, bonded, insured, and have been in business 5+ years.
Check their reviews on HomeGuide and Google.
Ask for references with contact information.
Confirm all cleanup is included in the quote.
Ask for beginning and end dates
Avoid hiring the company with the lowest bid as quality may suffer.
Never pay in full before the work begins. Follow a payment plan for work completed instead.