How Much Does It Cost to Add a Second Story?

Typical Range:

$80,000 - $600,000

Find out how much your project will cost.

Cost data is based on research by HomeAdvisor.

Updated January 17, 2022

Reviewed by Robert Tschudi, Expert Home Building and Remodeling Contributor.

Written by HomeAdvisor.

Building a second story addition typically costs between $100 and $300 per square foot. For complex projects with high-end materials, it could cost as much as $500 per square foot.

A partial second story addition may cost around $80,000 to $250,000, whereas adding a full second-story to your home could range from around $100,000 to $600,000 or more. Costs vary depending on your location, quality of materials used, and the size and complexity of the addition.

Average Cost to Add a Second Story

Average Cost$175,000
High Cost$600,000
Low Cost$80,000

Second-Story Material Prices

The quantities and types of materials used will depend on the size and scope of the project. Below are examples of common materials required for most second story additions (whether partial or full). Typically, materials will be at least 50% of your total budget.

MaterialAverage Cost
Roofing materials$100 – $1,000 per square foot
Drywall$0.40 – $0.65 per square foot
Insulation$0.50 – $5 per square foot
Flooring$0.50 – $15 per square foot
Electric wiring$6 – $8 per foot
Plumbing$4.50 per square foot
Staircase$50 – $100 per step
Foundation strengthening$5,000
Painting$25 – $50 per 350 square feet
Windows$150 – $650 per window
Siding$3 – $12 per square foot
Framing$3 – $6 per square foot
HVAC$25 – $60 per square foot
Doors$40 – $500 per door
Lumber$1 – $5 per square foot

Costs and Fees to Hire Second-Story Addition Professionals

You’ll typically hire a general contractor to complete a second-story addition on a home. Rather than an hourly rate, general contractor fees are usually about 10% to 25% of the total construction project cost.

Depending on your needs, you’ll have to factor in the cost of dealing with various other professionals during the project. These will usually include:

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Second Story Addition Cost Factors

Adding a second story is a big project, and various factors can influence the amount you will spend. We recently added a second story to a 950-square-foot house,” says Bob Tschudi, an Expert Review Board Member and Raleigh, N.C.-based general contractor. “One surprise cost was that the municipality required that we have the newly-constructed building re-surveyed to ensure that the structure's roof was within 2 inches of what we proposed. So it’s critical that you hire a contractor who understands blueprints built to specification.”

Size and Shape

It’ll cost more to add a full second-story addition on top of a 2,000 square foot single story than building an apartment over a garage or a partial second story on top of a 1,000 square foot home. Complex shapes also increase installation costs.

Quality of Finish

If you opt for slate roof tiles, luxury hardwood flooring, or architecturally designed windows, this will cost more than asphalt shingles, carpets, or standard double-hung windows.

While selecting a higher quality finish can reduce the frequency of repairs, you will reduce your costs by selecting materials wisely.

Location

The cost to hire contractors in desirable city locations will be more than in rural locations. However, there will be more contractors to choose from in the built-up areas.

Foundation Work

Depending on the type of second-story addition you’re planning and the structure of your existing home, the foundations may not be strong enough to support the additional weight.

You’ll need to hire a structural engineer to establish whether there’s a requirement for further foundation work before the project begins. Additional foundation support work costs could be $5,000 or more.

“To add the second story, we had to jackhammer out boulders under the house before we could pour new concrete footings and piers, “ says Tschudi. “Then we had to install a costly parallel-strand-lumber (PSL) column from the pier to the steel beam—we were creating an open-concept first floor so the engineering had to be right.”

Temporary Housing

Timelines for constructing a full second story addition can be around six to 12 months. Even partial additions can mean you have to be out of your house for as much as three to six months. If you don’t have an obliging relative or motorhome you can reside in temporarily, you may need to factor in additional rental costs for the duration.

Cost to Add a Second Story Yourself

Typically, labor costs make up 30% to 50% of your total second-story addition budget. While tackling the entire project without the help of contractors isn’t advisable unless you’re an experienced builder, there will be places where you could save costs. For example, you can do interior and exterior painting or laying floors if you’re handy, and it may save you around $1,000 or more.

DIY vs. Hiring a Building Contractor

Hiring a building contractor not only ensures a high standard of work, but they can subcontract electricians and plumbers and keep the project on track, safe, and on budget. Most contractors will help with building permit applications and liaise with other professionals such as architects and engineers.

Tackling a second story addition on your own without understanding the complexities of constructions and building code requirements can result in a project going over budget, takes years to complete, and may not be up to local building standards. You could end up with an unsafe home that’s difficult to insure or sell.

FAQs

Is it better to build up, out, or replace altogether?

Home addition costs vary considerably depending on their size and complexity. If you have limited space for building out and your foundations don’t need strengthening to build up, it may be more cost-effective and practical to build a second story. If there are zoning restrictions relating to building height or you want to stay in your home during construction, building out is better.

Depending on the complexity of the additional story and the age and condition of your home, it can sometimes work out cheaper to demolish the existing building and start again. But this won’t make sense if you’re planning a simple partial second-story addition or you have a historic home full of character.

How do I find the best contractor for the job?

The pros involved in your second story addition can make or break your project. When searching to hire a local building contractor, take the time to get multiple comparative quotes.

Ask to see portfolio photos, follow up on references, and check contractor credentials—they must have a license and insurance. Get a written contract before work begins and check all the details. This includes timelines, work descriptions, cost breakdowns, payment schedules, and permit details.

How can I keep the costs down on my second story addition?

Compromising is often the key to keeping the costs down on your projects. While you might not want to go with budget finishes, you don’t need to choose the most high-end options. If your architect suggests a different, simpler layout to keep the costs down, don’t dismiss it without proper consideration. Also, you could make some savings by tackling some of the more straightforward elements of the building work yourself.

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