Structural Beam Replacement When Your Crawl Space Cannot Wait
Support beams carry the weight of your home's entire floor system. When moisture or pests compromise them, every joist and floor above is at risk.
On cost: Structural beam replacement varies by beam size, span, crawl space accessibility, and the condition of bearing points. Typical projects range from $2,500 for a single accessible beam to $8,000 or more for complex multi-beam situations or those requiring engineered lumber and new pier supports.
Overview
Structural Beam Replacement
The main girder beams and support beams in a crawl space are the primary load-bearing members of the floor system. They span between foundation walls and piers, carrying the floor joists that in turn support the subfloor and everything above. When these beams are compromised by moisture-driven rot, pest infestation, or overloading, the consequences extend throughout the floor system above. Structural beam replacement is the appropriate solution when beams have degraded beyond the point where repair or reinforcement is sufficient. Ground Up Foundation Repair provides beam replacement in crawl spaces throughout Middle Tennessee, using properly sized dimensional lumber or engineered lumber products to restore full structural capacity.
Structural beam replacement involves temporarily supporting the floor loads that the failing beam carries, carefully removing the compromised beam while protecting adjacent framing, and installing a properly sized replacement beam in its place. The replacement is secured to foundation walls, piers, or posts using appropriate hardware and fasteners. The process requires careful structural analysis to ensure the new beam is correctly sized for the span and load it must carry.
Wondering if this is the right fix for what you are seeing? Learn more about the warning signs: Broken or Cracked Floor Joists in the Crawl Space and Mold on Crawl Space Framing . Or browse the full Problem Signs library for framing repair.
Installation Process
How we install structural beam replacement
Structural Assessment and Replacement Planning
A Ground Up technician inspects the failing beam, assesses the full extent of decay or damage, and determines the appropriate replacement beam size and species. For beams with significant span requirements or unusual loads, engineered lumber such as laminated veneer lumber may be specified. The assessment also identifies the condition of the posts, piers, and bearing points that will support the new beam.
Temporary Shoring Installation
Before the failing beam is disturbed, the floor loads it carries are transferred to temporary shoring installed in the crawl space. This distributes the structural loads safely during the replacement process and prevents floor movement or further damage above. Shoring must be adequate for the full live and dead loads of the floor system.
Removal of the Compromised Beam
The damaged beam is carefully disconnected from the framing it supports and from its bearing points. In cases of advanced rot or pest damage, the beam may be cut into sections for easier removal through the crawl space access point. All debris is removed from the crawl space and disposed of properly.
Preparation of Bearing Points
The bearing points where the new beam will rest, including foundation wall pockets, steel posts, and concrete piers, are cleaned, assessed for damage, and repaired if needed. Bearing hardware, post caps, and beam seats are installed as appropriate to meet current structural standards and provide positive connections between the beam and its supports.
Installation of the Replacement Beam
The new beam, pre-treated with borate-based wood preservative to resist biological activity, is positioned in place and set on its bearing hardware. Joists are reconnected to the new beam using joist hangers or toe-nailing per engineering specifications. The floor system is checked for level and alignment before temporary shoring is removed.
Moisture Control and Final Inspection
With the new structural beam in place, the crawl space is assessed for moisture control measures needed to protect the new framing. A vapor barrier, dehumidification system, or full encapsulation may be recommended and installed as part of the project. A final walkthrough confirms that floor flex has been resolved and the repair is complete.
The beam is the backbone of the floor system. When it goes, everything above it is at risk. I have seen homes where the homeowner thought they just had a squeaky floor, and when we got in the crawl space the main girder was completely hollow from termites. Replacing it correctly, with the right size lumber and proper bearing hardware, makes a real structural difference that you can feel underfoot the same day the job is done. Derek Veselich, Owner, Ground Up Foundation Repair
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
Structural Beam Replacement questions
A beam that has lost more than 30 percent of its cross-section to rot or pest damage typically requires replacement rather than repair. Beams that are compromised at their bearing points, where they rest on foundation walls or posts, are particularly critical because this is where the highest stress concentrations occur. A professional probe inspection determines the degree of structural compromise and the appropriate response.
A girder beam is the primary horizontal structural member that runs perpendicular to the floor joists and carries them over longer spans. It is typically larger in cross-section than a joist and bears on foundation walls, steel posts, or concrete piers. Floor joists are the secondary members that span between the girder and the rim joist. Beam failure has more widespread consequences because it compromises all the joists it supports.
Sistering is sometimes appropriate for beams with localized or early-stage damage, but it is more complex than joist sistering because of the larger member sizes and higher loads involved. Heavily compromised beams, especially those with damage at their bearing points, are generally better candidates for full replacement. Ground Up evaluates each situation individually.
Yes. A compromised beam often allows mid-span deflection in the joists it carries, which translates to a soft, bouncy feel across a wide floor area. Replacing the beam with properly sized new lumber restores the designed stiffness of the floor system, and most homeowners notice an immediate improvement in floor feel.
In most Middle Tennessee jurisdictions, structural framing repairs including beam replacement require a building permit. Ground Up manages the permit process where applicable and ensures all structural work meets local building code requirements.
More Solutions
Other solutions we offer
Beam Repair
Structural beams throughout a crawl space home serve distinct load-carrying roles, the sill plate transfers floor loads to the foundation wall, rim joists close off the floor system at the perimeter, and secondary beams support floor joists between the main carrier and the foundation. When any of these members is damaged by rot, insect activity, or physical stress, the floor system above loses support. Ground Up Foundation Repair identifies the affected beam, determines the appropriate repair method, and restores full structural capacity without disrupting the living space above.
Carrier Beam Repair
The carrier beam, also called the main girder, is the primary horizontal member that supports your floor joists and transfers their load to posts and the foundation. When a carrier beam cracks, sags, or rots, every joist it carries becomes compromised, causing widespread floor movement across an entire section of your home. Ground Up Foundation Repair assesses carrier beam damage, determines whether repair or replacement is appropriate, and restores full load capacity with minimal disruption to the living space above.
Crawl Space Jack Installation
Crawl space support jacks are adjustable steel columns installed on concrete footings beneath the floor framing of a crawl space home. They provide permanent supplemental support for floor joists and carrier beams that have deflected beyond what sistering alone can address, for spans that are too long for the existing framing depth, or for homes where the original post spacing was inadequate. Because they are adjustable after installation, crawl space jacks also allow incremental floor leveling without additional structural work. Ground Up Foundation Repair sizes, spaces, and installs support jacks to match the load conditions of each specific home.
Floor Joist Repair Plates
Floor joist repair plates, also called mending plates, joist plates, or structural connector plates, are heavy-gauge galvanized steel plates fastened across a crack, split, or notched section of a floor joist to restore local bending and shear capacity. They are most effective when damage is localized to a specific point along an otherwise sound joist, rather than distributed along its length. Repair plates are a faster and lower-cost solution than sistering in specific circumstances, and they are frequently used in combination with sistering when a joist has both a discrete crack point and overall reduced stiffness. Ground Up evaluates each joist individually and recommends the repair method, plates, sistering, or full replacement, that matches the actual damage pattern.
Floor Joist Repair
Floor joists are the horizontal structural members that span from beam to beam beneath your subfloor, carrying the weight of everything in your home. When they are damaged by moisture, rot, or pests, they lose load-bearing capacity and the floors above begin to flex, bounce, or sag. Floor joist repair restores the structural capacity of compromised framing through sistering, partial replacement, or full joist replacement, depending on the extent and nature of the damage. Ground Up Foundation Repair specializes in crawl space framing repair across Middle Tennessee, where humid conditions make joist damage an especially common problem.
Floor Leveling Services
Uneven floors are more than a cosmetic problem, they signal that the framing or foundation beneath them has shifted, weakened, or settled unevenly. Ground Up Foundation Repair diagnoses the root cause of sloping, bouncy, or sagging floors and develops a targeted leveling plan. Depending on the cause, floor leveling may involve jacking sagging joists, sistering damaged members, installing or adjusting steel support posts, or addressing the foundation settlement that started the movement. We restore floors to level without disturbing finished flooring wherever possible.
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