Crawl Space Jacks and Support Posts
Sagging beams and floors in crawl space homes can be stabilized and releveled with correctly installed support jacks, restoring structural capacity to the framing system.
On cost: $2,000 to $8,000 depending on the number of jacks required and footing conditions.
Overview
Crawl Space Jacks and Adjustable Support Posts
Crawl space jacks, also called adjustable support posts or screw jacks, are steel support columns installed in the crawl space to shore up sagging main beams, replace failed wooden support posts, or add supplemental support where beam span is too long for the original framing. In Middle Tennessee homes built on pier-and-beam foundations, the original support posts were often solid wood or short masonry piers. When the wood rots or the masonry piers settle and tip over time, the main beam loses its mid-span support and sags, causing the floors above to deflect.
Adjustable steel crawl space jacks are installed on concrete footings or bearing pads set on or into the crawl space floor. The column is extended to contact the main beam, and a leveling screw at the top allows precise height adjustment. Raising the jack gradually, over multiple visits to allow the house to adjust without damage to finished surfaces, allows the sagging beam to be returned to a level or near-level position.
Wondering if this is the right fix for what you are seeing? Learn more about the warning signs: Bouncy or Springy Floors and Mold Growth in the Crawl Space . Or browse the full Problem Signs library for crawl space repair.
Installation Process
How we install crawl space jacks and adjustable support posts
Structural Assessment
The crawl space beam system is mapped, identifying main beams, the original post locations, current bearing conditions, and the extent of deflection. A floor measurement is taken above to quantify the amount of sag.
Footing Preparation
For each new jack location, a concrete pad is poured or an existing footing is verified as capable of supporting the transferred load. Bearing pad sizing is determined by the load being transferred.
Jack Installation
Steel adjustable jacks are positioned on footings and extended to contact the underside of the main beam. Initial contact is made without applying upward pressure.
Gradual Lifting
Jacks are raised incrementally, typically no more than 1/8 inch per day, to allow the house structure to redistribute loads and stresses without damage to framing connections or finished surfaces.
Locking and Final Inspection
Once the target elevation is achieved, jacks are secured at the adjusted height. The floor above is re-measured to confirm improvement. All bearing connections are inspected for adequacy.
Crawl space jacks are one of the most direct structural repairs we do. We put the support back where it was lost, and the floor stops deflecting. The key is raising the structure slowly so nothing cracks.
Why Ground Up
The difference is in the diagnosis
Get several quotes and you'll see a wide range of prices. The gap isn't luck. It's whether the contractor finds the actual cause and stands behind the work.
- In-house certified crews: we never subcontract your repair
- Optional independent third-party engineer review on larger jobs
- Honest three-tier triage: we tell you what can wait, in writing
- Family owned from the same Shelbyville Highway address since 2009
FAQ
Crawl Space Jacks and Adjustable Support Posts questions
Floors that have sagged gradually over years can typically be raised significantly, but attempting to return them to perfectly level in one operation risks cracking drywall and disrupting framing connections. Ground Up raises floors incrementally to a structurally sound position.
Quality steel adjustable jacks with concrete footings are designed as permanent structural elements. They do not rot like wooden posts and can be re-adjusted in the future if additional settling occurs.
Jacks are installed specifically where beams have lost support or where beam spans exceed their design capacity. A structural assessment determines the correct locations and number of jacks needed.
More Solutions
Other solutions we offer
Crawl Space Moisture Control
Crawl space moisture control is not a single product. It is a strategy that combines multiple solutions to address the different sources of moisture that affect a crawl space. In Middle Tennessee homes, moisture enters the crawl space as vapor from the soil, as condensation from warm humid outdoor air, as liquid water from rain intrusion, and from plumbing or HVAC leaks. Effective moisture control identifies which of these sources are active in a specific crawl space and applies the appropriate solutions in the correct sequence. The goal is a crawl space that maintains relative humidity below 60 percent throughout the year without continuous intervention.
Crawl Space Access Doors
The crawl space access door is the primary maintenance access point for the crawl space and, in a sealed encapsulated crawl space, the last gap in the moisture and pest barrier. A standard wood-framed or uninsulated access door is a significant thermal and moisture bypass: it allows outdoor air and humidity to enter the sealed crawl space during inspection or maintenance access, and between visits if the door fits poorly. Ground Up installs sealed, insulated crawl space access doors that fit tightly, are weatherstripped, and include a latch that maintains compression against the frame.
Crawl Space Drainage Systems
A crawl space drainage system is an interior water management solution installed at the perimeter of the crawl space floor to intercept water that enters through stem walls, rises from the soil, or drains off the crawl space walls. The system channels that water to a sump basin where a pump discharges it away from the home. In Middle Tennessee, where clay soils retain water after heavy rain and seasonal water table elevation is common in many neighborhoods, interior drainage is often the most practical and durable solution for crawl spaces that experience recurring water entry.
Crawl Space Water Removal
Crawl space water removal is the process of extracting standing or pooled water from the crawl space floor, assessing the scope of any damage caused, identifying the water source, and developing a plan to prevent recurrence. In Middle Tennessee, crawl space flooding most commonly occurs during and after heavy rain events when drainage systems are overwhelmed, when downspouts discharge near the foundation, or when the seasonal water table rises to the crawl space floor level. Ground Up provides water removal service as part of a comprehensive assessment: we pump out the standing water, identify the entry source, document any damage to framing, insulation, and mechanical systems, and present a repair and prevention plan.
Crawl Space Waterproofing
Crawl space waterproofing is the process of preventing or managing water entry into the crawl space to keep framing dry and structurally sound. In Middle Tennessee, crawl spaces deal with three primary water sources: surface water that flows in through foundation vents or over grade during rain events, groundwater that seeps through the perimeter stem walls during extended wet periods, and condensation that forms when humid summer air contacts cooler surfaces inside the crawl space. An effective waterproofing system addresses all three sources, redirecting surface water with grading and downspout extensions, capturing seepage with interior drainage channels, and reducing condensation with vapor barriers and sealed enclosures. Ground Up designs and installs crawl space waterproofing systems sized for each home's specific conditions.
Crawl Space Access Wells and Hatch Doors
Crawl space access hatches and exterior access wells are often overlooked until they fail. An interior hatch that is uninsulated, poorly sealed, or too small to allow practical entry undermines the encapsulation system every time it is opened, and makes annual maintenance impractical. Exterior access wells that fill with water, have deteriorated doors, or allow pest entry compromise the encapsulation perimeter. Upgrading access as part of a crawl space repair project ensures that the system can be inspected and maintained efficiently for its full service life.
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