Cost to Bump-Out Addition in San Antonio, TX (2026)

If you’re budgeting a bump-out addition in San Antonio, most projects run $8,531-$42,653, 15% below 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.

$8,531-$42,653 in San Antonio

15% below the national average · 0.85x cost multiplier

Expect to pay $8,531-$42,653 for a bump-out addition in San Antonio, about 15% below the national benchmark. The Southeast region's contractor market and material costs account for most of this difference. The detailed breakdown below shows how budget, mid-range, and premium projects compare at San Antonio prices.

Cost Breakdown in San Antonio

Line ItemLowMidHigh
Cost per sq ft$77$136$213
Materials$3,780$8,033$17,010
Labor$4,524$8,294$16,589
Permits$1,134$1,890$2,835
Design$756$1,418$2,835
Total$10,194-15% vs. national avg$19,635-15% vs. national avg$39,269-15% 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 San Antonio may shift costs slightly.

MaterialCost/UnitBest For
Cantilevered (No New Foundation)$90-$130 per sq ftSmall 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 ftBump-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 ftKitchen 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 ftLarge 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 San Antonio

San Antonio Estimate

Typical Range

$8,531-$42,653

vs. National Average

15% below national

Cost Multiplier

0.85x

Cost Per sq ft

$77-$213

This 0.85x estimate prices San Antonio 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 →