How much does it cost to replace floor joists?
How much does it cost to replace floor joists?
$350 – $1,000 average cost per joist
$5,000 – $10,000+ average cost per room
$10,000 – $30,000 average cost per entire level of home
Average cost of replacing floor joists
The average cost of replacing floor joists is $350 to $1,000 per joist. The cost of replacing rotten floor joists in the entire room costs $5,000 to $10,000+. For a whole-house project, expect to spend $10,000 to $30,000. Factors such as accessibility, home age, joist material, and additional repairs influence the final price.
| Project scope | Average cost |
|---|---|
| Per joist | $350 – $1,000 |
| Per room | $5,000 – $10,000 |
| Whole house | $10,000 – $30,000 |
Replacing floor joists is a crucial task that ensures the structural integrity and safety of your home. Whether due to damage from moisture, pests, or simply age, compromised joists can lead to uneven floors, sagging, and even potential collapse if not addressed promptly.
The number of joists you’ll need to replace depends on these factors:
Material: The type of joist (dimensional lumber, engineered I-joists, LVL, or steel) influences strength and spacing requirements.
Joist spacing: The distance between joists, typically 16 inches, but up to 24 inches on center, can vary based on codes and load requirements.
Span length: Longer spans between support walls require more or stronger joists to maintain structural integrity.
Load-bearing capacity: The expected floor load determines the size and number of joists needed. Residential floors usually require 40 PSF (pounds per square foot) live load and 10 PSF dead load.
Building codes: Local regulations dictate minimum requirements for joist size, spacing, and materials based on the structure's use and location. Consult building codes in your area for specific requirements.
Consult with a structural engineer or licensed contractor to ensure your floor joist replacement meets all necessary requirements and will perform well in the long term.
Cost to replace floor joists by material
Floor joists come in various materials, each with unique benefits and costs. Traditional dimensional lumber is still common for smaller-scale projects, while engineered products like I-joists and LVL provide greater strength and span. Steel joists, though less frequent in homes, offer superior durability at a higher cost.
| Type | Average cost per linear foot* |
|---|---|
| Dimensional lumber | $2 – $8 |
| Engineered I-joists | $3 – $12 |
| Laminated veneer lumber (LVL) | $4 – $15 |
| Steel joists | $5 – $20 |
*Materials only; not including labor cost
Dimensional lumber
Dimensional lumber joists cost $2 to $8 per linear foot for traditional solid wood used in residential construction. They’re widely available and affordable but have limitations in span and can warp or shrink over time. Contractors typically use them in older homes or small projects where long spans are unnecessary.
Engineered I-joists
Engineered I-joists cost $3 to $12 per linear foot and consist of an OSB web between LVL or lumber flanges. They are strong, consistent, and can span longer distances without sagging. Commonly used in modern residential and light commercial construction, they are ideal for floors and roofs.
Laminated veneer lumber (LVL)
LVL joists cost $4 to $15 per linear foot and are made from thin wood veneers glued together to form strong, stable beams. More expensive than traditional lumber, they offer greater strength and longer spans. You can use LVL joists for projects that require high load-bearing capacity and rigidity, such as in large open spaces.
Steel joists
Contractors use steel joists in residential, industrial, and commercial construction for their superior strength and resistance to warping, shrinking, and pests. Steel joists are more expensive at $5 to $20 per linear foot and require specialized installation. They are ideal for long spans and heavy loads.
Consult a structural engineer when selecting joist materials. Their expertise can help you choose the most suitable and cost-effective option based on your specific load requirements, span distances, and long-term performance needs.
Floor joist replacement cost factors
Several factors affect the cost of replacing floor joists:
Accessibility: Joists in crawl spaces or unfinished basements are easier to replace than those under living areas which require removing the flooring.
Home age: Older homes may have additional complications like extensive rot, poor accessibility, and the need for additional support or repairs of outdated wiring or plumbing that increase costs.
Labor costs: Labor costs vary based on the regional wage rates, the complexity of the project, and the experience of the contractor.
Building permits: Most districts require permits costing $50 to $200 for structural work like joist replacement.
Subfloor replacement: Replacing joists often requires removing and replacing the subfloor, which costs $2.20 to $4.75 per square foot.
Flooring replacement: New flooring costs $4 to $15 per square foot if the existing flooring needs to be removed and replaced.
Additional repairs: Addressing the root cause of joist damage and making necessary repairs adds to the overall cost:
Water damage restoration costs $4 to $12 per square foot, depending on the amount of and type of water and the equipment needed.
Termite treatmentl costs $225 to $2,500 to treat with chemical or bait stations, while severe infestations requiring whole-home termite tenting cost $2,000 to $8,000.
Foundation repair costs $4,500 to $20,000, depending on the house size, foundation depth, and the repair method used.
Alternative joist and subfloor repairs
Some repairs do not require a complete joist replacement and can be addressed with easier and less costly fixes. The cost for sagging floor repair ranges from $300 to $2,000 for surface-level repairs, while more extensive structural repairs can be significantly higher.
These are some alternative repair options to complete joist replacement:
Sistering joists: This repair costs $150 to $325 per joist and involves reinforcing damaged joists by attaching new joists alongside the existing ones.
Blocking and bridging: For minor sagging or reinforcing weak areas, adding blocks or bridging between joists can enhance stability and reduce floor bounce.
Subfloor patching: For localized damage, such as small areas of rot or holes, patching the subfloor with new plywood can be an effective solution costing $100 to $300.
Leveling compounds: You can use self-leveling compounds to even out minor dips and uneven areas in the subfloor. This method is suitable for minor issues and can be a quick fix.
For a broader overview of flooring repair costs, check out our comprehensive flooring repair cost guide.
Floor joist replacement FAQs
Can you replace floor joists without removing the floor?
Replacing floor joists without removing the floor is possible if the floor joists are accessible through a basement or crawl space. However, full floor removal often provides better access and ensures a comprehensive repair.
When do you replace floor joists?
You should replace floor joists when they show signs of considerable damage or deterioration. Common indicators include:
Visible sagging
Bouncy or uneven floors
Cracks in walls or ceilings
Visible rot or insect damage
Replacement is also necessary if anything has weakened the integrity of the joists, such as water damage, fire, or structural modifications.
Who can replace floor joists?
Only licensed and experienced professionals, such as general contractors or structural repair specialists, should replace floor joists. The job requires expertise in structural engineering, carpentry, and building codes. DIY attempts are not recommended due to the complexity and potential safety risks involved.
How long does floor joist replacement take?
A small, localized repair might take 1 to 2 days while replacing joists in an entire room could take 3 to 5 days. Larger projects involving multiple rooms, or an entire floor can extend to 1 to 2 weeks. Factors like accessibility, additional repairs, and unforeseen issues can affect the timeline.
Do you need a permit to replace floor joists?
In most areas, replacing floor joists requires a building permit since it is a structural modification that affects the building's integrity and safety. The permit process ensures that the work meets local building codes and standards. Always check with your local building department to understand specific requirements before starting the project.
Getting estimates from floor repair contractors
For the most accurate quotes from a floor joist repair service, consider the following:
Contact at least 3 contractors to get a range of estimates to compare.
Ensure the contractors are licensed, insured, and bonded.
Verify their credentials and check for any complaints or reviews on trusted consumer sites like HomeGuide and Google.
Ask for a detailed written breakdown of the costs, including labor, materials, permits, and any additional fees.
Choose contractors with specific experience in floor joist replacement. Ask for references or examples of similar projects they have completed.
Determine whether the contractor plans to repair or replace the joists. Sistering a joist (reinforcing it with another joist) is cheaper than a full replacement. Ensure the method aligns with your needs and budget.
Confirm the contractor will handle the necessary permits.
Discuss the project timeline and ensure it fits your schedule.
If moisture or pests caused the damage, address the root cause to prevent future problems. Discuss potential additional costs for these preventive measures with your contractor.
Questions to ask a floor joist repair company
Ask the flooring repair service these important questions:
Are you licensed and insured to perform structural repairs like joist replacement?
How much experience do you have with replacing floor joists, and can you provide references?
Will you conduct a thorough inspection to determine the extent of joist damage?
How do you determine which joists need replacement versus repair?
What type of new joists do you recommend, and why?
Will you provide a detailed written estimate for the joist replacement work?
How long will the joist replacement process take?
Do you handle any necessary permits for structural work?
How will you ensure the new joists are properly sized, spaced, and level?
Will you address any issues with mold, rot, or pests discovered during the process?
Do you offer any warranty or guarantee on your joist replacement work?
What's your policy if unforeseen issues arise during the joist replacement process?
Using our proprietary cost database, in-depth research, and collaboration with industry experts, we deliver accurate, up-to-date pricing and insights you can trust, every time.