Crawl Space Jacks Guide (2026)
Crawl space jacks (adjustable support posts) fix sagging floors and provide structural support, costing $500–$2,000 per jack installed. Here is what you need to know about types, installation, and costs.
$500–$2,000
Per Jack
$2,000–$6,000
Typical Project
$200–$500
Engineer Consult
Types of Crawl Space Jacks
Adjustable Steel Support Jack
$100–$300The most common type. A steel post with a threaded screw mechanism that allows precise height adjustment. Sits on a concrete footing and supports a beam or joist above.
Lally Column (Steel Post)
$80–$200A fixed-height steel column, sometimes filled with concrete. Cut to exact height during installation. Very strong but cannot be adjusted after installation.
Telescoping Jack Post
$50–$150A temporary or semi-permanent adjustable post. Good for quick leveling but not approved as permanent structural support in most building codes.
Smart Jack System
$400–$800An engineered steel support system with a galvanized post, base bracket, and engineered footing. Designed specifically for crawl space foundation repair by companies like Supportworks.
When You Need Crawl Space Jacks
Installation Process
1. Structural Assessment
A structural engineer or foundation specialist evaluates the crawl space, identifies weak points, and determines how many jacks are needed and where to place them.
2. Footing Preparation
A concrete footing pad (typically 24" x 24" x 12" deep) is poured at each jack location. The footing must cure for 24–48 hours before the jack is installed.
3. Jack Placement
The adjustable jack is positioned on the footing and raised to contact the beam or joist above. A steel plate distributes the load across the wood member.
4. Gradual Adjustment
Jacks are raised slowly over days or weeks — typically 1/8 inch per day — to avoid cracking drywall or causing other damage above as the floor levels out.
5. Final Check
Once level, the jack is locked in position. The contractor verifies the floor is level and the load is properly distributed.
FAQs
How much do crawl space jacks cost?
Crawl space support jacks cost $500–$2,000 per jack installed. The jack itself costs $100–$300, while professional installation with a concrete footing runs $400–$1,700 per jack. Most homes need 2–6 jacks, putting the total project cost at $1,000–$10,000.
When do you need crawl space jacks?
You need crawl space jacks when floors are sagging or bouncy, floor joists are spanning too far without support, existing support beams or posts are damaged, you are removing a load-bearing wall above, or a home inspection identified insufficient structural support in the crawl space.
How long do crawl space jacks last?
Quality steel crawl space jacks last 50+ years when properly installed on a concrete footing. Galvanized or powder-coated jacks resist rust. The concrete footing should be at least 24 inches square and 12 inches deep to prevent settling over time.
Can I install crawl space jacks myself?
While DIY installation is possible, professional installation is recommended. Improper placement can cause more structural damage, and you need to correctly size the footing and jack for your load requirements. A structural engineer consultation ($200–$500) is worthwhile before any jack installation.
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