Home Addition Cost · 500 Sq Ft · 2026
A 500-square-foot addition is one of the most common ways NJ and PA homeowners add a real room — a family room, a primary suite, or a first-floor bedroom and bath. Here’s what one actually costs in 2026 and what moves the number.
500 Sq Ft Addition Cost by Scenario
| Scenario | Typical 2026 cost |
|---|---|
| Single-story, no plumbing (family room, bedroom) | $125,000 – $150,000 |
| Single-story with a full bath or wet bar | $145,000 – $175,000 |
| Primary suite (bedroom, bath, walk-in closet) | $165,000 – $190,000 |
| Two-story / complex rooflines & foundation | $180,000 – $200,000+ |
These are all-in ranges — design, permits, foundation, framing, mechanicals, and finishes. Roughly $250 to $400 per square foot depending on what the space contains and how the addition ties into the existing house.
What Moves a 500 Sq Ft Addition’s Price
Plumbing is the biggest swing. A 500 sq ft family room or bedroom with no water lines is far cheaper per square foot than the same footprint holding a bathroom or a kitchen. Adding a bath or kitchen can move the number $30,000 or more.
One story vs. two. A single-story addition needs its own foundation and roof; a second-story addition avoids the foundation but requires reinforcing the structure below and rebuilding the roof. Both are real projects — the cost depends on your home.
How it connects. Matching rooflines, siding, and floor heights so the addition reads as original to the house takes more work than a boxy bump — and it’s the difference between adding value and looking added-on.
500 Sq Ft Addition FAQs
How much does a 500 square foot addition cost per square foot?
For a 500 sq ft addition, expect roughly $250 to $400 per square foot all-in in the NJ and PA market — lower for a simple single-story room, higher when the space includes a bathroom or kitchen or is built as a second story.
Is a 500 sq ft addition cheaper than adding a second story?
Not always. A single-story 500 sq ft addition needs a new foundation and roof, while a second-story addition of the same size avoids the foundation but requires reinforcing the structure below. Which is cheaper depends entirely on your existing home — we assess both at the site visit.
What can you fit in a 500 square foot addition?
Plenty — a large family room, a primary suite with a bath and walk-in closet, a first-floor in-law bedroom and bath, or an expanded kitchen and dining area. The use case is the single biggest driver of cost.
Get Your Real Number
Planning a 500 sq ft addition?
We’ll walk your home, talk through the layout, and give you a line-itemed estimate — not a ballpark.
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