How Much Does It Cost to Add a Second Story in 2025?
Adding a second story costs an average of $175,000
The average cost to add a second story falls between $100,000 and $250,000. Most homeowners spend an average of $175,000, with some projects costing up to $600,000, depending on the scope and finishes.
The addition size, material requirements, quality of finishings, permits, and cost of temporary housing all impact the total price.
Expect to reinforce, repair, or even replace the foundation so it can handle the extra load.
A full addition involves complete roof removal, whereas a partial addition only involves minor modifications.
General contractors charge 10% to 20% of the total cost to manage the project, and hiring a professional helps ensure that your project stays on track and is completed to the highest standard.
This article was updated using automation technology and thoroughly reviewed for accuracy by HomeAdvisor Editor Ryan Noonan.
The cost to add a second story ranges from $80,000 to $600,000, with most homeowners spending an average of $175,000. The average cost range is between $100,000 and $250,000. The total price depends on the addition size, materials, and quality of finishes.
Most projects average $100 to $300 per square foot; however, using high-end materials can increase costs to $500 per square foot. Knowing these variables up front helps you set a realistic budget, and hiring a professional home addition builder to oversee your second story addition ensures that structurally sound, durable results.
Cost Factors for Adding a Second Story
Various factors, including the addition size, materials, quality of finishes, and foundation work required, impact the total cost of adding a second story to your home.
Size and Shape
Your home’s size and footprint drive much of the project cost. Plan on $100 to $300 per square foot, but premium materials can push that figure to $500. Irregular footprints also add to the price.
The more square footage you add, the more your costs increase. A full addition to a standard 1,500-square-foot home ranges from $150,000 to $450,000, whereas a partial addition costs an average of $300,000.
| Square Footage | Average Cost Range |
|---|---|
| 800 | $80,000–$240,000 |
| 1,000 | $100,000–$300,000 |
Materials
Materials account for nearly two-thirds of the cost of building a second story. The type, quality, and amount of materials required determine the total price. Your location also affects the cost of materials, with varying roofing, framing, and insulation requirements depending on your climate. For example, roofing costs $4.35 to $11 per square foot.
Finishing Quality
The quality of finishes, such as doors, windows, flooring, and countertops, chosen for the project significantly impacts the total cost. High-quality materials, such as stone siding, marble countertops, or hardwood floors, increase costs. Opt for cost-effective options, such as vinyl siding, laminate countertops, or engineered hardwood flooring, to keep the total cost down.
Foundation Work
Most single-story homes weren’t built to carry an extra floor. A contractor will likely need to reinforce, repair, or even replace the existing foundation before framing starts. Reinforcement and repair start at $5,000, but you can pay up to $600,000. A full addition is a large project that involves removing the entire roof and repairing the foundation to accommodate the additional square footage. You’ll also spend more on labor and materials like windows, roofing, and insulation.
A partial second-story addition covers only one portion of the house, leaving more of the original structure intact. A partial second-story addition costs an average of $300,000.
Labor
Start by hiring an architect to translate your ideas into buildable plans and blueprints. Rather than providing an hourly rate, architects charge an initial fee of 8% to 20% of the total project cost. The cost to draw blueprints is an additional $1,740.
Once the architect has drawn up the initial designs, a structural engineer can evaluate them and ensure your home has the structure to support the new addition. The average cost to hire a structural engineer is $550.
Once the blueprints and structural design are approved, a construction manager can oversee the process. Construction managers charge a fee of 10% to 20% of the total project cost. Their fee covers the cost of design, budgeting, permits, and hiring subcontractors such as electricians, carpenters, and HVAC specialists.
Often, your construction manager will coordinate the cost of required subcontractors and provide a complete labor estimate for the project.
| Contractor | Cost per Hour |
|---|---|
| Plumber | $45–$200 |
| Electrician | $50–$150 |
| Painter | $20–$50 |
Permits
A second-story addition always requires the proper building permits. The average cost for a building permit ranges from $1,200 to $2,000, depending on the project complexity and your location. If your local municipality denies the permit, you may need to hire legal assistance to help you appeal the decision.
Post-Construction Cleaning
Once construction wraps, expect plenty of dust and debris both inside and out. While contractors may do a rough cleaning of the space, you’ll likely want to hire a professional cleaner to make it move-in ready. The average cost of post-construction cleaning ranges from $300 to $700, depending on the amount of work required.
Temporary Housing
Because crews will cut into the roof and main structure, most homeowners arrange temporary housing during the build. Depending on the project's complexity, you may need accommodations for two to 12 months. Prices vary depending on your location and the type of housing. Many homeowners opt for a short-term rental, an extended-stay hotel, or a mobile home.
Does Adding a Second Story Increase Home Value?
A well-executed second-story addition can lift your home’s resale price, but the exact bump hinges on location, design, and market conditions. Extra square footage almost always attracts buyers—and in some areas, the potential for rental space sweetens the deal—but talk with a local real-estate pro before counting on a specific return.
Budgeting for Adding a Second Story
A second-story build is a major investment, but these strategies can help keep costs in check:
Do a partial addition rather than a full addition to reduce the cost of labor and materials.
Choose budget-friendly finishes and fixtures.
Dispose of debris yourself to reduce labor costs.
Complete the post-construction clean-up on your own.
Avoid paying for temporary housing by finding a friend or family member to stay with while your home is under construction.
Compare quotes from local home addition builders to find the most cost-effective option in your area.
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.
Frequently Asked Questions
For many homeowners, building up is worth the expense because it provides the extra bedrooms or living areas that can’t be accommodated within the existing footprint. A larger, updated home often commands a higher resale price, recouping a sizable share of the project cost while allowing you to stay in the neighborhood you love. Run the numbers with a real estate agent and contractor to ensure the expected return and day-to-day benefits align with your goals.
Whether it makes more sense to build up or out depends on your lot, budget, and local code. Building up preserves yard space and involves less foundation work, but you may need to vacate the home during construction. Building out avoids staircases and can proceed while you stay put; however, it encroaches on the yard and may face setback limits. Compare both options with your contractor before making a decision.
A structural engineer will first inspect the existing foundation for cracks, footings, and load capacity. Depending on the findings, the crew may pour new concrete footings, install steel or concrete piers, add reinforced beams, or tie additional rebar into the slab. These upgrades redistribute the weight of the new floor and bring the structure up to code. Your contractor will outline the specific reinforcement plan and timeline once the engineering report is complete.
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