Nassau County's Dormer & Home Extension Specialists | SERVING ALL OF LONG ISLAND
Free Estimates · Licensed & Insured · Serving Long Island Since Day One
At Madden Development, our multiple industry accolades are a testament to our unwavering commitment to excellence and distinguish us as the top choice for premium home remodeling contractors
Dormer and Home Extension Long Island Neighbors Always Call
If you are looking for a dormer contractor or home extension builder on Long Island that you can trust, Madden Development is who your neighbors call. We have built dormers and home extensions across Nassau County and Suffolk County for years, and our crew brings over 100 years of combined experience to every single project. We are locally owned, we know Long Island, and we have the 5-star reviews to back it up.Before you think about moving, call us. We have helped hundreds of Nassau County homeowners add the space they needed — without leaving the neighborhood they love.
Our Services
From dormers and extensions to full custom builds — we do it all in Nassau County.
Renovations
Custom Home Builds
Sell Us Your Home
Dormers
Extensions
What We Do
Dormers
We build dormers on Cape Cods, Colonials, and Ranches all across Long Island. A full shed dormer can turn your attic into two bedrooms and a full bathroom. We handle everything — architectural plans, permits, construction, and finish. You don't lift a finger.
Home Extensions
Need a bigger kitchen? An extra bedroom? More living space? A home extension is almost always the smarter move over buying new on Long Island right now. We build rear extensions, side additions, and bump-outs across Nassau and Suffolk County.
Second Story Additions
We add full second floors to ranch homes and single-story houses across Long Island. If your family has outgrown your footprint but you love your lot, a second story addition solves it completely.
Whole House Renovations
From gut renovations to full interior transformations — kitchens, bathrooms, open-concept conversions, basement finishing. One team handles it all.
Custom Home Builds
Build on your land or ours. We work with you from the first sketch to the final walkthrough. Custom homes across Long Island starting at $500,000.
From Concept to Completion
Consultation and Design
Our project process begins with an initial consultation where we'll discuss your vision, budget, and timeline.
Construction and Installation
Once the design has been finalized and approved, our skilled professionals will begin the construction process.
Final Inspection and Approval
After the construction and installation process is complete, we'll conduct a final inspection to ensure that everything is up to code and meets our strict quality standards.
Why Homeowners Across Long Island Choose Madden Development
We are not a large company that hands your job off to whoever is available. When you work with us, you get one dedicated team from the first consultation to the day we hand you the keys. Our crew has over 100 years of combined experience building dormers and home extensions on Long Island. We know Nassau County permits, we know Suffolk County permits, and we know exactly what your municipality requires before we ever break ground.We are fully licensed and insured. Every project we build is permitted, inspected, and up to code. No shortcuts that come back to bite you when you sell. And we are local — we live and work on Long Island, and our reputation here means everything to us.Our customers give us 5 stars because we show up, we communicate, and we finish what we start.
How It Works
Free ConsultationWe come to your home, look at the property, and tell you exactly what is possible. No pressure, no commitment. Just a real conversation about your home and what you want to do with it.
Plans & PermitsWe handle all architectural drawings and file every permit with your Nassau or Suffolk County municipality. You never have to deal with the building department.
ConstructionOur crew handles everything — framing, roofing, insulation, windows, and interior rough-in. We keep your home clean and your family's life as undisturbed as possible throughout.
Final Inspection & HandoverWe walk through with the inspector, sign off on every detail, and hand you a finished, fully permitted space.
Serving All of Long Island
We build dormers and home extensions across Nassau County and Suffolk County — East Meadow, Levittown, Westbury, Hicksville, Roslyn, Roslyn Heights, Roslyn Harbor, East Rockaway, East Hills, Salisbury, Williston Park, Manorhaven, Glen Head, Old Westbury, Woodbury, Syosset, Bethpage, Merrick, Lynbrook, Rockville Centre, Malverne, Manhasset, Glen Cove, and surrounding communities throughout Long Island.Not sure if we cover your area? Call us at (516) 875-4663 and we will let you know.
Everything You Need to Know
We serve Nassau County, NY. Specifically: Levittown, Westbury, Salisbury Estates, Roslyn, and Roslyn Harbor.
We are a full service home renovation company and commercial builder. Whether you want a custom built home, a small remodel, or help with your construction planning, we have it all.
For most projects, it takes a few days to a couple of weeks. For custom design builds it can take longer.
Every job is different, but we only use the highest quality materials for each project. We will work with you throughout the design process to choose top-quality materials that fit your budget and vision.
If you're doing a small remodel or renovation project, you can expect pricing to vary widely based on the size of the project. For custom built homes, our homes start at $500,000.
We will work closely with you in the design process and once construction starts you are welcome to be involved as much as you would like to be. Regardless, we keep constant communication about the status of the project so you are always aware of the progress being made.
Transform Your Home TodaY
Take the first step towards creating their dream living space, by partnering with Madden Development to bring their vision to life.
