Dormer Addition Cost

On February 25, 2026 By newsroom Topic: Home Services

Adding a dormer to your home enhances natural light, increases space, and improves curb appeal. Costs vary widely based on size, style, roof type, and materials. Here’s a detailed breakdown:

Average Costs

| Metric | Cost | |------------------------------------|---------------------------| | Per Square Foot | $80–$200 | | Small Window Dormer | $3,000–$8,500 | | Bathroom Dormer | $20,000–$55,000 | | Attic Dormer | $19,000–$30,000 | | Labor | $30–$50 per hour | | Permit Fees | $390–$1,930 |

Cost by Dormer Style

| Dormer Style | Cost per Square Foot | |--------------------|--------------------------| | Shed Dormer | $75–$120 | | Gable Dormer | $110–$150 | | Nantucket Dormer | $95–$140 | | Flat Dormer | $80–$125 | | Hip Dormer | $115–$135 | | Prefab Dormer | $65–$90 |

Cost Factors

Dormer Size
50 sq. ft.: $4,000–$10,000
100 sq. ft.: $8,000–$20,000
200 sq. ft.: $16,000–$40,000
Roof Type
Asphalt: $5–$12 per sq. ft.
Metal: $8–$14 per sq. ft.
Clay or Slate: $12–$24 per sq. ft.
Materials
Windows: $75–$1,500 each (depending on material)
Siding: $1–$20 per sq. ft.
Cladding (for water protection): $2–$15 per sq. ft.
Foundation Reinforcement
Reinforcement: $4,000–$12,000
Repairs: $2,000–$8,000
Labor and Structural Work
Expect ~50% of your total cost to go toward labor (~$6,000 average).

Common Add-Ons

Flooring: $12.50 per sq. ft.
HVAC Extension: ~$3,500
Gutters: $4–$40 per linear foot

How to Save Money

Opt for prefab dormers instead of custom designs.
Choose simpler styles like flat or shed dormers.
Install a single window per dormer instead of larger, more elaborate designs.
Use budget-friendly materials, like asphalt shingles or vinyl siding.
Select a flatter roof slope for easier and cheaper installation.

DIY vs. Hiring a Pro

Savings Potential: $1,000–$15,000 in labor costs.
Risks: Structural errors, water damage, or improper permits.
Recommendation: Hire a professional for safety and accuracy, especially for complex projects.

Adding a dormer is an excellent investment for extra space and style. Proper planning, cost-efficient choices, and hiring experienced contractors can make your dream dormer a reality!