The average U.S. homeowner spends $3,250 to replace a main house support beam, but the cost can range from $1,500 to $25,000, depending on the scope of the project.
A structurally sound home depends on its main support beam, so it’s important to replace a damaged beam to prevent serious structural damage. Replacing a main house support beam costs an average of $3,250, but costs often range between $2,000 and $10,000, depending on the complexity of the project, the materials used, and more.
The material your support beam is made from will be a major determining factor in replacement costs. Natural wood and laminated veneer lumber (LVL) beams and natural wood are more budget-friendly options, while longer-lasting options like steel I-beams, glued laminated timber, also called glulam, and aluminum will cost more.
| Support Beam Material | Average Cost Range per Linear Foot |
|---|---|
| Laminated Veneer Lumber (LVL) | $3 – $12 |
| Natural Wood | $5–$30 |
| Glulam | $6 – $40 |
| Steel | $6–$20 |
| Aluminum | $13–$30 |
Hiring a general contractor to install a new support beam costs an average of $650 to $2,300 on top of the cost of materials. Contractor costs may increase depending on how difficult the beam is to access, whether they need to work around electrical wiring and plumbing, and the extent of necessary finish work.
Since altering a support beam nearly always requires the sign-off from a local structural engineer, budget between $350 and $750 for their expertise as well. The cost of a structural engineer report depends on the complexity of the beam and what it holds up. The inspection of a load-bearing wall, for example, will cost just $100 to $200 per hour, while a roof inspection and report cost up to $600.
In addition to materials and labor, there may be other factors adding to the cost of replacing a main house support beam. Support beam replacement is a complex project, and each step will involve additional costs.
All structurally related projects in your home must begin with an inspection. The cost of a foundation inspection, for example, averages $600. Inspection costs can run higher for more complex projects, such as when investigating a larger horizontal foundation crack.
The cost of building permits varies depending on where the beam lives in your home but can range up to $2,000 if the project is considered new construction. Thankfully, a contractor will research and pull permits for you before getting started.
Contractors will typically include the cost of temporary support posts in their flat fee since they will bring the materials along for the job. If you are only installing a support post—also known as a lally column—the process will cost an average of $2,500. These posts support the area with the missing beam before replacement. For example, you will see lally columns around a missing basement support beam to fortify the floors overhead.
Unless we're talking about exposed beams in your rustic living room or in the case of a pier and beam foundation, you'll need to remove drywall to expose them. Drywall removal costs between $0.30 and $0.45 per square foot.
Replacing a structural element of your home is not advisable, especially for load-bearing support beams. In most areas, and especially in condos or housing developments, you'll likely need to call a licensed and certified contractor to obtain a permit for the work and handle the project.
You can address issues that may impact the structural integrity of your home or escalate project costs by watching for signs of termites, dry rot, or the need for foundation repair. Call a pro to help get these resolved as early on as possible.
In some cases, you may be able to repair a main house support beam instead of replacing it, but a structural engineer should make that call. Once a support beam has been damaged, the structural integrity of your house is at risk, and repairing the beam may compromise its effectiveness. While repairing a support beam may save you some money in the short term, a replacement will ensure your house is structurally sound and no further damage occurs.
While you never want to cut corners when altering the structural elements of your home, there are ways to be smart about the process. Here are some ways to keep costs low when replacing a main house support beam:
Investigate the issue early, especially something as severe as sagging floor foundation repairs. Your costs will increase the longer the rotten beam affects the structure of the area around it.
Speak to at least three general contractors to compare costs and ensure their payment schedule meets your needs.
Discuss possible cost-effective material solutions, such as LVL beams.
Work with a contractor who can address all surrounding issues at once in one lump sum to cut down on travel and overhead fees.
Research local permit fees ahead of time to understand how to fit them into your budget.
A structurally sound main house support beam is critical to your home’s structural integrity. While replacing a damaged support beam may not directly increase your home’s value, failing to replace it can cause structural damage and make your house difficult to sell or insure. Support beam replacement is a necessary maintenance cost to keep your house structurally sound and will help it retain its value when it comes time to sell.
Home is the most important place on earth, which is why Angi has helped more than 150 million homeowners transform their houses into homes they adore. To help homeowners with their next project, Angi provides readers with the most accurate cost data and upholds strict editorial standards. We extensively research project costs to develop the pricing data you see, so you can make the best decisions for you and your home. We rely on reputable sources, including the U.S. Bureau of Labor Statistics, academic journals, market studies, and interviews with industry experts—all to ensure our prices reflect real-world projects.
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Call a foundation repair pro to replace a rotted support beam. Your contractor will likely install temporary support to the area while replacing the beam with new wood or steel. Load-bearing elements of your home—such as the horizontal beams that run along your floors, walls, roof, and ceilings—should be inspected by a trained structural engineer. Call these experts the moment you detect rot, water damage, or foundation issues in your home.
You should pick steel for your new support beam for a few reasons. While steel is more expensive than other materials, such as laminated veneer lumber or glulam, it offers the following benefits:
Fire-resistant
Unaffected by pests
Longer-lasting
Stronger against water damage (when galvanized against rust)
Detecting a weak or rotted beam is a great time to look into the underlying cause and start on some other home projects. Bring in experts to double-check for high moisture levels that lead to dry rot, encapsulate your crawl space or basement by calling a local crawl space encapsulation pro, or inspect your property for wood-damaging pests.
