How Much Does Replacing Floor Joists Cost in 2024?

Average Cost to Replace Floor Joists

Floor Joist Replacement Cost Factors

Several factors can influence the total cost of a floor joist replacement. For instance, if your floor is tough for a pro to reach, it will require more time and labor to fix, which drives up costs.

Accessibility

If possible, your contractor will replace your joists from below, either from a crawl space or an unfinished basement ceiling. However, if you have rotting joists in a second-story room, your contractor needs to remove and replace the existing carpet or hardwood and subflooring on top of the joists to expose the damage, which significantly increases the price of the job. Furniture and appliances also need to be removed, which you can do yourself to reduce labor costs.

Flooring and Subflooring

Flooring and subflooring installation costs range between $6.50 to $23.50 per square foot. You can lower flooring installation costs by installing a floating floor.

If your floors need to be removed and replaced as part of your joist replacement, the type of flooring you choose will impact your total cost. For instance, the cost to repair hardwood floors or tile is higher than laminate floors, and requires a more complex installation with higher labor and material costs.

Labor

Labor makes up the bulk of the cost of repairing or replacing floor joists. Most general contractors charge by the day rather than by the hour, with average rates ranging from $300 to $500 per day. If they’re bringing a helper or laborer, the average rate for that person’s work is an additional $150 to $250 per day.

Labor rates vary depending on the difficulty of the job and the contractor’s experience. Rates may also depend on your location and how far the contractor has to travel to your home. Preparing your space in advance by removing rugs, furniture, and appliances can reduce the time your contractor has to spend at your home, saving you money on labor.

Extent of Damage

The cost to replace all joists on one level of a typical home is $10,000 to $30,000, based on a 300-square-foot space. If damage is limited to one room or section, your total will likely fall between $2,000 and $10,000.

The more extensive the damage to your floor joists, the higher your costs. Insects like termites or prolonged water exposure can damage joists, so you’ll need to pay to exterminate the insects or fix the moisture problem before you can begin replacing the floor joists. These costs can vary greatly depending on the nature of the issue.

If you’ve noticed sagging floors, insect damage, or moisture, contact a general contractor in your area for professional floor joist repair.

Floor Joist Prices by Type

Floor joist costs vary quite a bit based on the type of joist you use. There are three main types of floor joists commonly used in home construction.

Engineered I-Beam Floor Joists

The average cost for a standard 16-foot engineered I-beam is $40 per joist. This type of joist comes from plywood, oriented strand board (OSB), particleboard, or fiberboard placed between standard pieces of lumber in the shape of the letter “I.” Beam-shaped or truss-type engineered joists can span greater distances than other floor joists with little to no sagging over time.

2x10 Joists

A popular choice for floor joists, 2x10s cost about $10 per joist. They’re made from softwood lumber cut to custom lengths more easily than engineered I-beams. However, their natural wood construction can cause warping or bowing over time. Plus, they don't come in sizes that span the length of an average home. This means you’ll often need to purchase twice as many joists as you would I-beams, increasing your overall installation cost.

Open-Web Floor Truss Joists

Open-web floor truss joists feature two 2x4s that sandwich an inner wood or metal "web." These joists typically cost $30 to $70 per joist, depending on the type. They minimize shrinking, squeaking, and bowing. You can also fit electrical wires and some pipes through them, which can make construction easier. 

Floor Joist Total Installation Cost

Replacing floor joists is a major structural repair to your floor, often requiring the professional tools and knowledge of a trained contractor. The total project cost for full joist replacement is typically $5,000 to $20,000 for a 300-square-foot room. Additionally, unless your joists are easily accessible from a crawl space or an unfinished basement ceiling, joist replacement will likely also involve subfloor replacement costs and floor covering replacement.

Floor Joist Installation Cost Per Joist

Expect to pay anywhere from $100 to $2,000 per joist, depending on their accessibility and whether additional repair or replacement work is required. You may pay only $100 to $300 per joist if your contractor can easily access the joists from below.

However, if your joists are insulated or covered by flooring and subflooring, a complete replacement will likely cost $1,000 or more per joist. Most contractors price a full joist replacement job as a total project cost based on the number of joists replaced.

Floor Joist Replacement Cost by Extent of Damage

Joist replacement is usually necessary when a joist has rotted away due to damage from insects or moisture. The scale of your floor repair project depends partly on the extent of this damage.

Sistering

On average, sistering will cost you $100 to $300 or more per joist. Sistering involves clearing rot, treating the wood, and laying a new joist beside the old one. However, these costs will increase if your contractor needs to open up a floor or ceiling to access the joists. 

Partial Room Replacement

A minimal joist replacement typically costs $2,000 to $5,000. If only part of your room suffered damage, you might only need to replace a few joists rather than all of them. Generally, the more joists you need replaced, the more you can expect to pay.

Full Room Replacement

Full room replacements typically cost $5,000 to $10,000, as damage extent is among the biggest factors affecting floor joist replacement costs. If your room experienced extensive damage throughout, you may need to replace all of the joists in the room.

Entire Level Replacement

In some cases, damage is so widespread that an entire level of a home is compromised. In this instance, you'll need to replace all of the joists on that level, typically costing $10,000 to $30,000. The larger your level, the more you'll likely have to pay. 

Floor Joist Replacement vs. Repair

Whether it’s better to replace or repair your damaged floor joists depends on the type and extent of the damage.

If your floor joists are cracked rather than rotten or significantly damaged, sistering can be an effective and affordable repair method. Sistering saves you from having to raise large floor sections to conduct replacements, which can strain the floor structure.

However, if your floor joists are rotten, damaged by moisture, or impacted by other major damage, it’s usually better to replace them. If you have a large number of cracked floor joists, it may be more cost-effective in the long run to replace them all at once.

Budgeting for Floor Joist Replacement

The cost of floor joist replacement depends primarily upon the size and extent of the damage and the accessibility of the space. A home inspector can help you estimate the extent of your floor joist replacements so you can budget for repairs or replacements.

Preparing the space in advance can also make your floor joist replacement project more budget-friendly. Clear away any furniture or appliances that could prevent your contractor from easily accessing the floor. Open access routes, such as crawl spaces or unfinished basement ceilings, offer an easier and more affordable way to reach floor joists.

Improving access and reducing prep time will save you money, so it’s worth rearranging furniture, removing rugs, and taking extra steps to prepare your home. If your repairs require removing a section of flooring, you can also explore flooring repair costs for tips on the best flooring solutions for your budget.

How HomeAdvisor Gets Its Cost Data

No place is more important than your home, which is why HomeAdvisor connects homeowners with local pros to transform their houses into homes they love. To help homeowners prepare for their next project, HomeAdvisor provides readers with accurate cost data and follows strict editorial guidelines. After a project is complete, we survey real customers about the costs to develop the pricing data you see, so you can make the best decisions for you and your home. We pair this data with research from 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.