How Much Does a Home Addition Cost in New Jersey? A 2025 Guide for Homeowners

If you're considering expanding your home in Montclair, Wayne, or Kinnelon, you're probably asking the big question: How much will this cost me? Home additions are one of the most valuable upgrades you can make—but the price can vary dramatically based on what you're building, where you're located, and how complex the job is.

In this guide, we break down realistic cost ranges, key pricing factors, and what to expect when planning a home addition in Northern NJ.

What’s the Average Cost of a Home Addition in NJ?

For most New Jersey homeowners, home additions cost between $250 to $400 per square foot. Here's a basic breakdown by type:

• One-room bump-out (bedroom, office): $75,000 – $100,000

• Kitchen extension: $100,000 – $160,000

• Primary suite addition: $120,000 – $200,000

• Garage or sunroom: $80,000 – $150,000

• Second-story addition: $180,000 – $300,000+

These are ballpark figures for typical homes in Essex, Passaic, and Morris Counties—actual quotes may vary based on materials, labor, site access, zoning, and scope of work.

What Drives the Cost Up or Down?

Several factors influence the final price of your home addition in NJ:

• Foundation work: New construction on a slab or crawl space costs more.

• Utility tie-ins: If you’re relocating plumbing or electrical lines, expect added costs.

• Interior finishes: Custom cabinetry, hardwood floors, or premium windows will raise the budget.

• Permit and inspection requirements: Each town (e.g., Montclair vs. Wayne) has its own process.

• Accessibility: Tight spaces or grading issues can affect excavation and equipment costs.

Is It Worth the Investment?

Yes—if done right. A well-designed addition can increase both livable space and home value. For example:

• Kitchen or bedroom additions can offer up to 60-70% ROI

• A second-story addition may double your square footage and resale appeal

• In-law suites or accessory dwelling units (ADUs) can create rental or multigenerational living opportunities

Real Projects, Real Numbers

At Kenly Construction, we’ve completed recent home additions in:

• Montclair: Second-story addition with new staircase – $240K

• Wayne: Kitchen and mudroom extension – $135K

• Kinnelon: Bedroom + bath suite over garage – $160K

Each project included architectural plans, permit handling, structural work, and full interior finishes.

Planning a Home Addition in 2025?

Start with a realistic budget, an experienced builder, and a clear idea of your goals. We’ll help you design a space that fits your home—and your future.

Schedule a Free Estimate with Kenly Construction today.