
If you're a homeowner in Long Island looking to add space, boost home value, or simply transform your house's curb appeal, dormers and extensions are two of the most impactful ways to do it. But before you break ground, it's important to understand what each project entails, what the local regulations are, and how to choose the right contractor for the job.
What Are Dormers and Extensions?

Dormers are structures that project from a sloped roof, usually containing a window. They can add headroom, natural light, and architectural interest to upper floors or attic spaces. Dormers are especially popular in Cape Cod and Colonial-style homes commonly found across Long Island.
Home extensions involve building out part of the existing structure to add more square footage. This could be a rear extension, side extension, or even a second-story addition. Extensions are ideal for growing families or homeowners who want to add bedrooms, bathrooms, or open-concept kitchens.
Why Long Island Homeowners Choose Dormers and Extensions
- Increase Living Space: Dormers can turn an attic into a livable bedroom or office. Extensions can add entire new wings to a home.
- Add Property Value: Homes with expanded square footage typically appraise higher.
- Stay in the Neighborhood You Love: Instead of moving, many Long Islanders choose to expand and improve.
- Customize Your Layout: Whether it's a bigger kitchen or a private guest suite, expansions let you tailor your home to your lifestyle.
Permits and Regulations in Nassau and Suffolk Counties
Local building codes vary across Long Island's many towns and villages. Common requirements include:
- Submitting architectural plans for approval
- Meeting setback and zoning requirements
- Passing safety inspections
- Securing permits before beginning construction
Be sure to work with a contractor familiar with your town's specific code, whether you're in Huntington, Smithtown, Hempstead, or anywhere in between. The team at LPS takes care of all of this for you.
How to Choose the Right Contractor in Long Island
- Experience with Dormers and Extensions: Ask to see before-and-after photos of similar projects.
- Local Knowledge: Choose a builder familiar with Long Island building codes and permitting processes.
- Licensed and Insured: Always confirm credentials.
- Transparent Estimates: Get detailed, written quotes and timelines.
- Strong Reviews and References: Look at Google, Yelp, and Facebook reviews or ask for referrals.
Budgeting for a Dormer or Extension Project
Costs can vary widely depending on materials, scope, and permits. Here's a rough range:
- Dormers: $15,000 - $50,000
- Single-Room Extensions: $25,000 - $100,000+
- Full Second-Story Additions: $100,000 - $250,000+
Plan for contingencies—unexpected costs can arise during demolition or structural changes. Timelines can range from 4 to 12 weeks for dormers and 3 to 6 months or more for extensions, depending on the scope of work, weather conditions, and municipal approvals. On Long Island, delays often stem from permit backlogs, so early planning is essential.
FAQ
1. Do I need a permit to build a dormer or extension in Nassau or Suffolk County?
Yes—most towns require zoning approval and building permits. We handle the entire process, from architectural plans to inspections.
2. How much does it cost to add a dormer or home extension on Long Island?
Typical costs range from $15,000–$50,000 for dormers and $25,000–$150,000+ for extensions, depending on size and scope.
3. How long does a dormer or home addition project usually take?
Dormers typically take 4–12 weeks, and full extensions can take 3–6 months, including permits and site work.
4. Can the addition match my existing home’s architectural style?
Absolutely—we custom design dormers and extensions to blend with your home’s style, materials, and neighborhood aesthetic.
5. Are there zoning or setback requirements I should know about?
Yes, each municipality has specific rules on height, setbacks, and lot coverage. We research and ensure full compliance before starting.
Final Thoughts
Whether you're considering a dormer to brighten up an attic or a full extension to accommodate a growing family, investing in your Long Island home is a smart move. With the right planning and team, your dream home can be built right where you already live.
Need help getting started with dormers and extensions? Contact us to schedule a consultation and learn what’s possible with your property.
Learn more about our home remodeling services.