Quick answer: A second story addition in Chicago usually costs about $300 to $450 per square foot with standard finishes, and $450 to $600 or more with high-end finishes. A partial addition over part of the house often runs $175,000 to $325,000, and a full second floor on a bungalow or ranch commonly runs $350,000 to $550,000 with standard finishes, and more with high-end finishes. The biggest cost drivers are foundation and structural reinforcement, removing and rebuilding the roof, the new staircase and new mechanical systems. Plan on 3 to 6 months for design and permits and 5 to 9 months of construction. AMG Proline gives a fixed written price after a free in-home visit. Call (708) 979-3298 or request a free estimate!
Licensed and bonded in Illinois (License #104.020448) · Remodeling since 2000 · BBB A+ rated · In-house trades · Read our Google reviews here!
When a Chicago family outgrows a bungalow, a Cape Cod or a ranch, the lot is often the limiting factor. City lots are narrow and suburban lots have setbacks, so building out is not always possible. Building up is. A second story addition can double the living space without giving up the yard, and it lets you stay in a neighborhood and school district you love. It is also the most structural project most homeowners will ever take on. This guide explains what drives the cost, how the structural work and permits work, and how long it really takes.
This guide goes with our home remodeling in Chicago service. If you are planning a larger renovation of the whole house at the same time, read Whole Home Remodel in Chicago.
Thinking about adding a second floor? We review your foundation, framing and zoning before we price anything. Call (708) 979-3298!
Second Story Addition Cost in Chicago by Project Type
These are planning ranges based on additions across Chicago and the suburbs. Your fixed price depends on the engineering, your finishes and what we find once the roof and walls are opened.
| Project type | Typical size | Planning range |
|---|---|---|
| Partial addition, such as a primary suite over part of the house | 400 to 700 sq ft | $175,000 to $325,000 |
| Full second floor on a bungalow or ranch, standard finishes | 900 to 1,300 sq ft | $350,000 to $550,000 |
| Full second floor with high-end finishes and multiple baths | 1,000 to 1,500 sq ft | $500,000 to $800,000+ |
| Addition over a garage | 300 to 600 sq ft | $150,000 to $275,000 |
Cost per square foot is useful for early planning, but it hides the fixed costs every addition carries: engineering, permits, roof removal, the staircase and new systems. Small additions often cost more per square foot than large ones for that reason.
Where the Money Goes
| Line item | What drives the cost | Typical range |
|---|---|---|
| Architect and structural engineer | Design, structural calculations, permit drawings | $20,000 to $60,000 |
| Permits and zoning | City or village permit fees, any zoning relief | Varies by town and scope |
| Foundation reinforcement | Enlarged footings, underpinning or new piers where the engineer requires them | $15,000 to $80,000+ |
| Roof removal and weather protection | Tear-off, temporary protection, scheduling around weather | $15,000 to $40,000 |
| Structural framing | Floor system, walls, beams, posts, new roof framing | $60,000 to $150,000 |
| New roof | Size, pitch and roofing material | $20,000 to $50,000 |
| Staircase | New stair, opening the first floor, finishes | $15,000 to $45,000 |
| Windows and exterior siding or masonry | Matching existing brick or siding, window count | $30,000 to $90,000 |
| HVAC | New zone or system for the upper floor | $15,000 to $40,000 |
| Plumbing | Bathrooms, laundry, new stacks and venting | $20,000 to $60,000 |
| Electrical | Service upgrade, new circuits in conduit | $20,000 to $50,000 |
| Insulation, drywall and interior finishes | Flooring, doors, trim, paint, closets | $50,000 to $150,000 |
| Bathrooms | Number of baths and finish level | $30,000 to $90,000 each |
We give one fixed written price covering every trade. Read Why We Quote Fixed Written Prices and In-House Trades vs. Subcontractors.
Structural Work: Can Your House Carry a Second Floor?
The first question is not design. It is whether the existing house can carry the new weight. A second story adds walls, floors, a roof, people, furniture and snow load, and all of it travels down through the first floor walls into the foundation.
The foundation
Many Chicago bungalows and ranch homes were built with footings sized for one story. A structural engineer reviews the foundation, often by digging test holes to see the footing size and condition. Depending on what they find, the plan may need:
- No foundation work, when the existing footings have enough capacity.
- Enlarged footings or new piers under specific points where new loads come down.
- Underpinning, which extends sections of the foundation deeper or wider.
The first floor structure
- Floor joists. Ceiling joists from a one-story house were rarely built to be a floor. Most additions add a new floor system on top.
- Load-bearing walls and beams. New beams and posts carry loads down to the foundation. If you also want an open first floor, the engineer plans both together. See Open Concept Kitchen: Removing a Wall.
- Wall framing. Exterior walls may need reinforcement to carry the new floor and roof.
The roof and weather
Most additions remove the existing roof. The house is open to the weather until the new walls and roof are framed and covered, so this phase is planned tightly, ideally between spring and fall, with temporary protection ready for rain.
Permits and Zoning
In the City of Chicago
- Building permit with architect drawings. A second story addition needs a full permit with plans prepared by a licensed architect, including structural drawings.
- Zoning limits. Each residential district sets a maximum building height and floor area ratio (FAR), which caps total floor area based on lot size. Many bungalow lots are already close to their limit, so the size of the addition may be capped.
- Setbacks. The new floor usually has to stay within required front, side and rear setbacks.
- Zoning relief. If the design goes beyond the limits, the project may need a zoning variation, which adds time and is not guaranteed.
- Landmark districts. Homes in a Chicago landmark district may need review of exterior changes before a permit is issued.
In the suburbs
Each village has its own permit process, zoning code and review times. Some require architectural review boards or HOA approval. For timelines, see our South Suburb Permit Timelines and our room-by-room permit guide.
We check zoning before design starts, so you know how large the addition can be before you pay for full drawings.
Want to know how big your addition can be? We review your lot, zoning and structure in one visit.
Design Decisions That Change the Price
- Full or partial floor. A partial addition saves money but still carries many of the same fixed costs.
- Stair location. The new staircase takes space on both floors. Placing it well can avoid moving kitchens or bathrooms.
- Number of bathrooms. Each bathroom adds plumbing, waterproofing and finishes. See our primary bathroom remodel guide.
- Roof style. Simple roofs cost less. Dormers, gables and complex lines add framing and roofing cost.
- Exterior match. Matching existing brick on a Chicago bungalow costs more than siding.
- Windows. Large and specialty windows add cost and structural work.
- Finish level. Flooring, tile, cabinets and fixtures can swing the budget by six figures.
How Long a Second Story Addition Takes
| Stage | Typical time |
|---|---|
| Feasibility, zoning check and engineering review | 2 to 6 weeks |
| Architectural design and permit drawings | 6 to 12 weeks |
| Permit review and approval | 4 to 12 weeks or more, longer with zoning relief |
| Foundation work and roof removal | 2 to 6 weeks |
| Framing, new roof and dry-in | 4 to 8 weeks |
| Mechanical, electrical and plumbing rough-in and inspections | 3 to 6 weeks |
| Insulation, drywall and finishes | 8 to 14 weeks |
| Final inspections and punch list | 2 to 4 weeks |
In total, most projects take about 8 to 15 months from first meeting to move-in, with 5 to 9 months of construction.
Can you live in the house during the work?
Many families move out for at least part of the project, especially while the roof is off and during heavy structural work. Others stay for the finish phase. Read Living at Home During a Remodel in Chicago to plan for it.
Hidden Costs in Older Chicago Homes
- Electrical service upgrades when the existing panel cannot carry the new floor.
- Asbestos in old roofing, siding or pipe insulation. See What Happens When Asbestos Is Found During a Remodel.
- Lead paint in homes built before 1978. See Lead Paint and Pre-1978 Homes.
- Sewer and water line capacity for added bathrooms.
- First floor repairs where the new stair and beams pass through finished rooms.
Second Story Addition vs Other Options
| Option | Best when | Trade-off |
|---|---|---|
| Second story addition | The lot is small and you need a lot more space | Highest structural cost and longest timeline |
| Rear or side addition | The lot has room and setbacks allow it | Uses yard space, needs new foundation |
| Attic finish with dormers | The attic has enough height and the structure allows it | Less space than a full floor |
| Basement finish or apartment | The basement is dry with good ceiling height | Below grade, with water and egress requirements |
| Moving | The neighborhood is less important than the house | Transaction costs and leaving the area |
For other ways to add space, read Kitchen Addition in Chicago and Basement Apartment Conversion in Chicago.
Second Story Additions Across Chicago
| Home type | Common in | What to plan for |
|---|---|---|
| Brick bungalows | Chicago neighborhoods and inner suburbs | Matching brick, FAR limits, foundation checks |
| Ranch homes | Orland Park, Tinley Park and the south suburbs | Long roof spans, stair placement, new HVAC zone |
| Cape Cods and older suburban homes | Hinsdale, Glencoe, Northbrook | Village design review, matching architectural style |
About AMG Proline
AMG Proline has been remodeling homes in Chicago and the suburbs since 2000. We’re licensed and bonded in Illinois (License #104.020448) and BBB A+ rated. Our own crews handle demolition, framing, waterproofing, tile and finish work, from our showroom at 4711 W 135th St, Crestwood, IL 60418. Learn more about us, see our projects, or read our Google reviews. Before hiring anyone for a project this size, read How to Hire a Licensed Contractor in Illinois.
Second Story Addition FAQs
How much does a second story addition cost in Chicago?
Most run about $300 to $450 per square foot with standard finishes and $450 to $600 or more with high-end finishes. A full second floor on a bungalow or ranch commonly runs $350,000 to $550,000 with standard finishes, and $500,000 to $800,000 or more with high-end finishes.
Is a second story addition cheaper than moving?
It can be, especially when you love your neighborhood and schools. Compare the addition cost with the price difference of a larger home plus selling and moving costs.
Can my foundation support a second story?
A structural engineer has to check. Some foundations can carry the load as they are, and others need enlarged footings, piers or underpinning.
Do I need an architect for a second story addition?
Yes. A permit for a second story addition requires drawings from a licensed architect, along with structural engineering.
What permits do I need in Chicago?
A full building permit with architect drawings. The design must also meet zoning rules for height, floor area and setbacks, and some homes need landmark review.
What is FAR and why does it matter?
Floor area ratio caps the total floor area of a home based on lot size. Many Chicago lots are close to their limit, which can cap the size of a second floor.
How long does a second story addition take?
About 8 to 15 months from first meeting to move-in, including 3 to 6 months for design and permits and 5 to 9 months of construction.
Can we live in the house during construction?
Many families move out while the roof is off and during heavy structural work, then return for the finish phase. It depends on the project and your household.
Does the roof come off completely?
Usually yes, over the area of the addition. That phase is planned tightly, with temporary weather protection, until the new structure is dried in.
Where does the new staircase go?
It needs space on both floors. The architect places it to fit the layout, often near the center of the house, to avoid moving kitchens or bathrooms.
Is a partial second story addition worth it?
It can be, for a primary suite or a couple of bedrooms. It costs less overall but carries many of the same fixed costs, so the price per square foot is often higher.
How do I get a price?
Call (708) 979-3298 or request a free estimate online. We visit, review your structure and zoning, and give you a fixed written price.
Get Your Free Second Story Addition Estimate
Call (708) 979-3298 · 4711 W 135th St, Crestwood, IL 60418 · Monday to Saturday, 8 AM to 7 PM
Categories
Wellness Center Build-Out in Chicago: Sauna, Cold Plunge, Plumbing and Electrical Planning
Quick answer: A wellness center build-out in Chicago usually costs about $150 to $350 per square foot in construction, before equipment, because saunas, cold plunges, steam rooms and showers add heavy electrical loads, water and [...]
Fitness Studio Build-Out in Chicago: Flooring, Ventilation, Showers and Cost
Quick answer: A fitness studio build-out in Chicago usually costs about $100 to $200 per square foot for a yoga, Pilates or barre studio without showers, $125 to $250 for strength and cycling studios, and [...]
Urgent Care Build-Out in Chicago: Exam Rooms, Medical Gas, Permits and Budget
Quick answer: An urgent care build-out in Chicago usually costs about $175 to $350 per square foot for construction, before medical equipment. A typical 3,000 to 5,000 square foot clinic with 6 to 10 exam [...]
Second Story Addition Cost in Chicago: Structural Work, Permits and Budget Ranges
Quick answer: A second story addition in Chicago usually costs about $300 to $450 per square foot with standard finishes, and $450 to $600 or more with high-end finishes. A partial addition over part of [...]
