Cost to Bump-Out Addition in Chicago, IL (2026)
If you’re budgeting a bump-out addition in Chicago, most projects run $11,750-$58,751, 18% above the $22,000 national average. What moves that number most is usually one thing: Foundation Type. On its own it can swing the cost by $0 - $15,000, so that’s the decision to slow down on before you sweat the smaller stuff.
Easiest place to save: Keep the bump-out to 2 feet or less so it can cantilever off existing framing - this eliminates foundation costs entirely.
$11,750-$58,751 in Chicago
18% above the national average · 1.18x cost multiplier
In Chicago, a bump-out addition runs $11,750 to $58,751 on average - about 18% above what homeowners pay nationwide. The Midwest market's labor costs account for most of the gap, with material pricing and local permitting fees adding to the spread. Use the cost table below to compare budget, mid-range, and premium options side by side.
Cost Breakdown in Chicago
| Line Item | Low | Mid | High |
|---|---|---|---|
| Cost per sq ft | $106 | $188 | $294 |
| Materials | $4,360 | $9,265 | $19,620 |
| Labor | $7,599 | $13,932 | $27,864 |
| Permits | $1,308 | $2,180 | $3,270 |
| Design | $872 | $1,635 | $3,270 |
| Total | $14,139+18% vs. national avg | $27,012+17% vs. national avg | $54,024+17% vs. national avg |
Budget
Small 60-80 sq ft bump-out, cantilevered over existing foundation, no foundation work needed, standard materials matching existing siding.
Mid-Range
100-150 sq ft bump-out with foundation piers or slab extension, mid-grade finishes, energy-efficient windows, basic electrical.
Premium
200+ sq ft bump-out with full concrete foundation, premium materials, custom windows, dedicated heating/cooling, high-end finishes.
Material Options
Material prices below are national averages; availability in Chicago may shift costs slightly.
| Material | Cost/Unit | Best For |
|---|---|---|
| Cantilevered (No New Foundation) | $90-$130 per sq ft | Small bathroom, closet, or bay window expansions of 2-3 feet depthLowest cost option, no excavation or foundation work, fastest construction |
| Concrete Pier Foundation | $110-$160 per sq ft | Bump-outs of 3-6 feet depth in moderate climatesGood for medium-sized bump-outs, minimal excavation, stable support |
| Poured Concrete Slab | $130-$190 per sq ft | Kitchen or family room bump-outs where a durable floor is neededSolid, stable, can support any size addition, good for kitchen/dining expansions |
| Full Perimeter Foundation | $160-$250 per sq ft | Large bump-outs over 150 sq ft or in areas with challenging soil conditionsMost stable, allows crawl space access, supports heavy loads and large bump-outs |
Other Projects in Chicago
Chicago Estimate
Typical Range
$11,750-$58,751
vs. National Average
18% above national
Cost Multiplier
1.18x
Cost Per sq ft
$106-$294
This 1.18x estimate prices Chicago labor from BLS Occupational Employment and Wage Statistics (May 2025) and applies a lighter regional adjustment to materials and permits, which vary less by metro than labor does. Actual bids vary by contractor, project scope, and timing.
See national average costs →