What Is a Dormer? A Complete Guide to Styles, Costs, and Benefits for Long Island Homes

Written By Ciro Cascella

When you think about expanding your living space, you may picture an addition or a full second story. But for many Long Island homeowners, adding a dormer is one of the most cost-effective and aesthetically pleasing ways to gain space, light, and functionality. In this guide, we’ll cover everything you need to know about dormers—from the different styles and costs to the practical benefits and how they can add long-term value to your home.

What Is a Dormer?

A dormer is a structural element that protrudes from the slope of a roof and typically includes a window. Dormers create usable space in the roof area and are often added to attics or upper floors to improve headroom, natural light, and ventilation.

In Long Island homes, dormers are commonly added to cape-style houses, colonials, and ranches to convert an unfinished attic into a livable room—often a bedroom, office, or bathroom.

Popular Dormer Styles

  • Gable Dormer: Also known as a doghouse dormer, this is the most traditional style, featuring a peaked roof and vertical walls.
  • Shed Dormer: With a flat roof that slopes in one direction, this dormer creates maximum interior space and is ideal for large expansions.
  • Hip Dormer: Has three sloped sides and integrates well with homes that have a hipped roof.
  • Eyebrow Dormer: Features a curved roof without vertical sides, often used for aesthetic appeal rather than function.
  • Wall Dormer: Built as an extension of the home’s exterior wall, creating a full vertical wall from the bottom up.

Benefits of Adding a Dormer

  • Increased Living Space: Transform your attic into a usable room without a full addition.
  • More Natural Light: Dormer windows brighten up formerly dark areas.
  • Better Ventilation: New windows improve air circulation.
  • Enhanced Home Value: Adding square footage and bedrooms boosts resale appeal.
  • Improved Exterior Curb Appeal: Dormers add architectural interest and dimension.

Cost of Adding a Dormer on Long Island

The cost of a dormer addition varies depending on size, complexity, and structural changes required. Here’s a general range:

  • Shed Dormer: $25,000 – $50,000
  • Gable Dormer: $10,000 – $30,000
  • Full Second-Story Rear Dormer: $60,000 – $100,000+

These figures include design, permits, framing, roofing, siding, windows, insulation, and interior finishing. At Cascella & Sons, we provide detailed quotes tailored to your home and goals.

Permitting and Regulations in Nassau & Suffolk County

Before adding a dormer, it’s essential to work with a licensed contractor familiar with Long Island’s zoning laws and building codes. You’ll likely need:

  • Architectural plans
  • Building permits from your town or village
  • Structural inspections
  • Proper setbacks and height limits

We can help navigate all of these steps for you.

Is a Dormer Right for Your Home?

If you want to add square footage and natural light without extending the home’s footprint, a dormer is a smart and stylish solution. It’s especially useful if you’re looking to:

  • Add an extra bedroom or home office
  • Create a second-floor bathroom
  • Improve ceiling height and comfort in attic spaces

Dormers offer tremendous value for their cost and are one of the top-requested remodeling projects for expanding homes across Long Island.

Work with Trusted Dormer Contractors on Long Island

At Cascella & Sons Construction, we specialize in dormer additions that are built to last. We’ll help you choose the right style, handle all design and permitting, and complete your project on time and on budget.

Visit our Our Work page to see examples of dormer additions we’ve completed for homeowners across Nassau and Suffolk Counties.

Get a Free Dormer Consultation

If you’re considering a dormer addition for your home, contact us today for a free consultation.

Let’s turn your attic into a beautiful, functional space.