Table of Contents for this Page
- Cinder Block Foundation Cost
- Cost Range for Cinder Block Foundations
- Average Total Costs
- Overview of a Block Foundation
- Cinder Block Foundation Cost Factors
- Cleaning Supplies Cost Details
- Permits, Inspection, Related Costs and Installation Time
- Related Projects
- DIY or Hire a Pro for this Project?
- Comparison Costs from Leading Resources
- Common Questions and Answers about Block Foundations
Average Cost of a Block Foundation
The cost range for a concrete block or cinder block foundation is $9,000 to $31,000 when the foundation is 800 to 1,600 square feet.
The low cost includes crawlspaces of 36” to 54”. Higher costs are for full foundations between 8 and 10 feet high. The cost per square foot is $11.25 to $24.50 based on the foundation’s footprint, not square feet of all space.
Cinder block foundation cost includes everything you would pay for when hiring a foundation contractor: Excavation, pouring footings, laying the block, filling some or all the core with concrete, installing reinforcement rebar and adding a concrete slab. Drain tile or a French drain is often installed around the foundation perimeter.
Interior piers and/or posts to support load-bearing beams may be included.
Average Cost Ranges
Overview of Cinder Block Foundations
Cinder block is an alternative option to a poured foundation for a crawlspace or a full basement. Cinder blocks are also called cinder masonry units, or CMU. A concrete block foundation costs more than a slab foundation but gives you space for mechanical equipment like a furnace and for storage or living space.
CMU foundations cost a little less in materials compared to poured foundations, especially when not all of the core is filled with concrete. But installation costs can be higher than with a poured foundation because laying block is time-consuming and block installers are well-paid.
There’s a concern too that cinder block construction is more prone to cracks along the block lines, which can lead to leaks into the crawl or basement. Filling the entire core alleviates much of the concern about leaks.
Most DIY homeowners choose block because it can be installed without heavy forms and by using bags of concrete and a small mixer rather than having concrete trucks and a pump in for the job. Yes, it is a slow and arduous process, but DIY block foundations cost about a third to half of those professionally installed.
Here are a couple tips before getting started.
First, before you decide to dig a foundation, a perc test should be done to determine that the soil types and seasonal water table allow for excavation. Most communities require this type of testing before issuing a permit for any foundation type. If you purchased the property recently, it’s likely that the seller had this done prior to being given permission to split the original property, if a split was made.
Secondly, a land survey, if one has been completed, might show where the property passed a perc test – and hence where acceptable foundation/building sites are located on the property.
Block Foundation Cost Factors
A cost range of $11.25 – $24.50 per square foot is wide. Let’s narrow it for you, so that you can better “guestimate” what cinder block foundation cost estimates you’ll get from local contractors.
- DIY vs Pro – Labor accounts for about two-thirds of the cost of a block foundation. While renting equipment and paying a higher cost for bags of concrete than for a truckload of it will eat into your potential savings, you should be able to around a third to half the price is you have the site excavated, pour your own footings and lay the block. But see the DIY or Not section below for more details.
- Foundation Height – The price range above begins with a 3-foot-high crawlspace. Full basements height is usually 8 foot, but 9 and 10 foot basements are popular for finished basements.
- Foundation Size – Bigger foundations come with a higher total price tag, but cost per square foot actually drops a little as the size increases due to basic economies of scale.
- Core Filling – There’s an ongoing debate about whether the entire core should be filled, as shown here or whether adding concrete every 4-6 feet is acceptable like on this job. Local codes often dictate the answer. If your ground is unstable, the foundation is partially or fully exposed, soils are especially heavy or seismic activity is likely, then filling the entire core is the right choice.
- Potential Freezing Weather – When concrete is poured at a time that a spring or autumn freeze is possible, an anti-freezing agent must be added to the concrete.
- Slab Installation – Unless you’re dealing with bedrock issues in a crawlspace, then most homeowners include a 4” concrete slab floor.
- Number of Corners – A 4-corner foundation is the simplest. When your home design has 6+ corners, cost of foundation installation rises.
- Site Conditions – Rocky soil, difficult access due to spring rains, a large number of trees to work around and other site challenges raise the cost.
- Excavation and Base Materials – Foundations must rest on stable, undisturbed soils. The amount of soil that must be removed to reach stable soils impacts excavation time and how much material must be installed beneath the foundations.
- Fees – You’ll need a permit (cost below), and if an engineer must be hired to complete the foundation design, cost can be significant.
- Insulation – While really a separate cost than foundation installation, insulation makes a crawlspace or basement more energy efficient and comfortable. Your options include standard insulation and spray foam insulation. Crawlspace encapsulation is recommended when there are concerns about moisture and mold in a crawlspace.
- Sump Pump Installation – Unless the soils beneath your foundation are “bone dry” all year, adding a sump pump to deal with seasonal or regular moisture around and beneath your foundation can prevent leaking and a flooded foundation.
Block Foundation Supplies, Services and Costs
As noted in our Slab Foundation Costimate, material costs, not including labor costs, are:
- $35 – $55 per Cubic Yard | Pea Stone or Gravel for beneath the slab and around the perimeter of the foundation
- $2.75 – $3.35 per Block | 8”x8”x16” Cored Concrete Blocks
- $110 – $160 per Cubic Yard | Mixed Concrete Delivered for Footings and the Core
- $3.50-$5.00 per Bag | Bags of Concrete – If you use 80lb bags, you’ll need 45 bags per cubic yard of concrete needed to fill cores or form the slab. That comes to around $158 to $225 per cubic yard plus mixer rental.
- $40/Day or $200/Week | Average Cost of Concrete Mixer Rental
- $0.12 – $0.20 per Square Foot | Vapor Barrier for beneath the slab
- $1.50 – $4.00 per Square Foot | Professional Exterior Waterproofing on any part of the foundation that is below grade
- $50/Gallon or $200/5-gallon | DIY Foundation Waterproofing with each gallon covering approximately 175 square feet
- $0.55 – $0.70 per Square Foot | Steel Rebar or Mesh Reinforcement
- $25 – $60 Each | Foundation vents, if required.
Estimating tip: One cubic yard of pea stone, gravel or concrete covers 108 square feet to a depth of 2”, 81 square feet to a depth of 4” and 54 square feet to a depth of 6”.
Foundation Size and Cost
Cost examples for crawl spaces are found in our Crawlspace Costimate.
Here are block foundation cost estimates for foundations from 8-10 feet in height. All examples include a 4” concrete slab floor.
In each example, the core might be partially filled (lower cost) or completely filled (higher cost).
Easy: Good access and site conditions near the road; 4-6 corners. Example: A flat or nearly flat small lot with sand or loam soil and dry conditions.
Average: Minor access issues such as wet soils or some trees or brush. Foundation up to 8 corners Example: Large suburban lot or a rural property with the building site well off the road. Damp conditions and/or possible freezing temperatures.
Difficult: 6 or more corners. Poor site conditions. Difficult access and concrete pump required. Example: A sloped lot possibly treed or with wet soils preventing easy access.
Let’s apply these general guidelines to cinder block foundation prices.
800 Square Feet – $15.00 – $24.50/square foot
- Easy: $12,000 – $15,350
- Average: $14,650 – $17,500
- Difficult: $14,250 – $19,600
1,200 Square Feet Foundation – $14.85 – $24.00/square foot
- Easy: $17,800 – $22,000
- Average: $20,500 – $24,750
- Difficult: $23,000 – $28,000
1,600 Square Feet Foundation – $14.50 – $23.80/square foot
- Easy: $23,200 – $28,500
- Average: $27,300 – $33,750
- Difficult: $31,900 – $38,100
2,200 Square Feet Foundation – $14.35 – $23.00/square foot
- Easy: $31,600 – $40,500
- Average: $37,900 – $44,800
- Difficult: $41,950 – $50,600
Permits, Inspection, and Labor Costs
Permits and Inspection
- $200 – $1,000 | Your foundation will require a permit that includes inspection of the footings and complete foundation. Cost factors are foundation size and fees where you live.
Homewyse gives an accurate estimate of labor costs for a block foundation – about two-thirds of the total cost. That’s roughly $6,000 to $20,000 for most foundations up to 1,600 square feet.
It adds up quickly when you consider these labor costs:
- Excavation | $100 – $200 per hour for an excavator and operator. Expect excavation to take 8-12 hours for a full foundation including transportation time plus unloading/loading the excavator. Total cost is $800 to $2,400.
- Base Materials with Delivery | $35 – $55 per cubic yard. Sand, gravel and pea stone are all options for forming a stable base for the slab of a foundation and for backfilling around it. A 1,600 square foot foundation needs 30-35 cubic yards of material at a cost of $1,500-$1,800.
- Vapor Barrier Installed | $0.25 – $0.50 per square foot. Most foundation installers insist on installing vapor barrier beneath a slab foundation.
- Concrete Delivery | $110 – $160 per cubic yard. A 1,600 square foot concrete floor that is 4” thick requires 20 cubic yards of concrete at a cost up to $3,200. The amount of concrete needed to fill the core depends on height of the walls and how much of the core is filled. The cost range for a 1,600 square foot foundation with 8-foot walls ranges from $1,500 to $2,700.
- Wages | $20 – $45 or more per hour. Wages vary from $20 for basic labor to $45/hour or more for block layers and concrete finishers. An average block foundation requires 100-200 hours of labor at a cost up to $9,000 total.
Time Required to Install a Block Foundation
This timeframe does not include weather delays or delays caused by scheduling conflicts for delivery and subcontractors.
- Up to 1 Day | Site Excavation
- Half Day | Pouring the Footings plus a few days to allow them to harden and get them inspected
- 3-10 Days | Laying the Blocks – time based on crew and foundation size
- 1-3 Hours | Filling the Core with concrete and rebar
- Up to 1 Day | Pouring and Finishing a concrete slab
A foundation is an essential part of home construction and creating a place of your own for you and your household. Here are a few projects related to this project.
Are You a Pro Home Foundation Company?
If so, head over to our Costimates Pro’s page, and help us make this page better and more accurate for both our visitors and your future customers.
DIY or Hire a Pro
Doing it yourself requires a range of skills and a lot of time on your hands.
A DIY job might look like this:
- Get your permit and, if necessary, hire an engineer or architect to design the foundation.
- Rent an excavator, mark the foundation footprint and dig it out – to 4’ beyond the footprint on all sides. For example, the hole for a 32’x48’ foundation should be 40’x56’.
- Dig the footing trenches, level them, add forms, reinforcing rebar, and pour/finish the footings (they must be “perfectly” level)
- Build your block walls
- Mix concrete on site or order a truck and pump to fill the core – install rebar as you go
- Add pea stone or gravel as a base for the slab
- Mix concrete or order a truck to pour the slab – this is a good step to leave to a truck/pro finisher to get a high-quality, seamless slab floor
- Add drainage around the footings/perimeter
- Backfill the foundation
Compare Costs from Leading Resources
- Homewyse: $15.75 - $20.25, Per Square Foot
- Hunker: $11.00 - $15.00, Per Square Foot
- HomeGuide: $12.00 - $18.00, Per Square Foot
- Forbes: $14.00 - $17.00, Per Square Foot
- HomeAdvisor: $9.00 - $15.00, Per Square Foot
Common Questions and Answers
How much is a block foundation?
$11.25 - $24.50 per square foot. Total cost is $9,000 to $31,000 based on wall height and foundation size.
Is a block foundation cheaper than poured?
No. The cost of a block foundation is about the same or a little higher because of the increased time and labor costs. If you DIY, then a block foundation can be cheaper.
How long does a block foundation last?
50 years minimum and more than100 years when properly installed and maintained.
How do I estimate the cost of a foundation?
Consider the number of square feet and multiply it by the cost per square foot above. Easy: $14.00 - $20.00 per square foot Average: $15.50 - $22.00 per square foot Difficult: $17.00 - $24.50 per square foot The higher the walls, from 3-10 feet, the higher the cost per square foot.
Is a poured foundation better than block?
Not necessarily. Discuss your project with local foundation contractors to determine the right material based on your foundation size and specific factors related to your property and homebuilding project.