Cost to Second Story Addition in St. Louis, MO

$88,000–$264,000 in St. Louis

12% below the national average · 0.88x cost multiplier

In St. Louis, a second story addition runs $88,000 to $264,000 on average — about 12% below 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 St. Louis

Line Item	Low	Mid	High
Cost per sq ft	$132	$220	$352
Materials	$35,200	$66,000	$123,200
Labor	$44,000	$74,800	$123,200
Permits	$4,400	$7,040	$10,560
Design	$6,160	$10,560	$22,000
Total	$89,760-12% vs. national avg	$158,400-12% vs. national avg	$278,960-12% vs. national avg

Budget

Full second story over a 1,000 sq ft footprint with standard materials, vinyl siding, builder-grade windows, and basic finishes. Minimal interior customization.

Mid-Range

1,200 sq ft second story with mid-grade finishes, fiber cement siding, energy-efficient windows, 3 bedrooms, 2 bathrooms, and dedicated HVAC system.

Premium

1,500+ sq ft second floor with custom architectural design, premium finishes, vaulted ceilings, master suite with luxury bath, and full structural engineering.

Material Options

Material prices below are national averages; availability in St. Louis may shift costs slightly.

Material	Cost/Unit	Pros	Cons	Best For
Wood Frame with Vinyl Siding	$150-$200 per sq ft	Most affordable construction method, fast framing, widely available contractors	Lower-end appearance, vinyl can look mismatched on older homes, less durability	Budget-conscious projects on homes that already have vinyl sidingMost affordable construction method, fast framing, widely available contractors
Wood Frame with Fiber Cement Siding	$200-$280 per sq ft	Durable, paintable, low maintenance, matches most existing home styles, fire-resistant	Higher material and labor cost than vinyl, requires painting every 10-15 years	Mid-range additions where exterior quality and longevity matterDurable, paintable, low maintenance, matches most existing home styles, fire-resistant
Wood Frame with Brick Veneer	$250-$350 per sq ft	Excellent curb appeal, matches brick first floors seamlessly, very durable	Heavy - may require foundation reinforcement, slow to install, expensive skilled labor	Brick ranch homes where matching the exterior is critical for resaleExcellent curb appeal, matches brick first floors seamlessly, very durable
Structural Insulated Panels (SIPs)	$220-$320 per sq ft	Superior insulation, faster framing, energy-efficient, airtight construction	Fewer experienced contractors, difficult to modify after construction, higher material cost	Energy-conscious homeowners in climate extremes who want long-term utility savingsSuperior insulation, faster framing, energy-efficient, airtight construction
Modular / Prefab Second Story	$130-$220 per sq ft	Factory-built sections reduce on-site time, weather exposure, and labor costs	Limited design flexibility, requires crane for installation, not available everywhere	Straightforward rectangular footprints where speed and cost control are prioritiesFactory-built sections reduce on-site time, weather exposure, and labor costs

Other Projects in St. Louis

Full Kitchen Remodel

Basement Finishing

Roof Replacement (Asphalt Shingles)

Back to national average for Second Story Addition

St. Louis Estimate

Typical Range

$88,000–$264,000

vs. National Average

12% below national

Cost Multiplier

0.88x

Cost Per sq ft

$132–$352

Estimates apply St. Louis's 0.88x regional cost multiplier to national averages. Actual bids vary by contractor, project scope, and timing.

See national average costs →