You love where you live. Your kids go to school here. Your neighbors are family. But your house feels smaller every year.
A dormer gives you the square footage you need without taking over your backyard or forcing you into a bigger mortgage somewhere else. It turns that dark, cramped attic into an actual bedroom, a home office with natural light, or a bathroom that finally gives everyone their own space in the morning.
On Long Island, zoning restrictions make it tough to expand outward. Lot sizes are tight. Setback rules are strict. Building up makes sense when building out isn’t an option. And unlike a full second-story addition, a dormer keeps costs reasonable while still adding real value to your home—both in how it lives and what it’s worth.
We’ve been doing dormer construction and home additions across Nassau County since 1972. We’re licensed, insured, and ranked in the top 1% of contractors in New York according to BuildZoom.
We answer the phone. We show up when we say we will. We keep the job site clean every day, and our crews treat your home like it’s theirs.
Old Bethpage homeowners call us because they know we’ve done this work hundreds of times in neighborhoods just like theirs. We understand local building codes, we pull the permits, and we handle inspections so you don’t have to figure it out on your own.
First, we come out to look at your attic and roof structure. We measure headroom, check framing, and talk through what kind of dormer makes sense—shed, gable, or a combination. We’ll also go over your goals: more bedrooms, a master bath, office space, whatever you’re trying to solve for.
Once we agree on a plan, we handle the design and pull permits with the town. Then we schedule the work around your life, not ours. Most dormer projects take a few weeks depending on size and complexity.
During construction, we protect your home with tarps and coverings, especially if weather’s a factor. Framing goes up first, then roofing, windows, insulation, and interior finishes. We clean up at the end of every day because we know you still live there. When we’re done, you’ll have a finished room that feels like it was always part of the house—plus the natural light and headroom that makes it actually usable.
Ready to get started?
A dormer isn’t just a roof bump. It’s structural work, weatherproofing, insulation, windows, and interior finishing. We handle all of it.
That includes framing the dormer into your existing roof structure, installing new roofing and flashing so nothing leaks, adding windows that meet code and actually open, insulating to Long Island standards so the room stays comfortable year-round, and finishing the interior with drywall, trim, flooring, and paint. If you’re adding a bathroom or upgrading electrical, we coordinate that too.
In Old Bethpage and across Nassau County, home values have climbed steadily over the last few years. Inventory is tight and buyers want space. A finished dormer adds livable square footage that shows up in your appraisal and makes your home more competitive if you ever do sell. But more importantly, it makes your life easier right now. You’re not tripping over each other. You’re not using the dining room as an office. You’ve got the room you actually need.
Cost depends on size, dormer type, and what finishes you want inside. A typical dormer that adds 150 to 200 square feet usually runs between $15,000 and $35,000 in Nassau County. That includes framing, roofing, windows, insulation, and basic interior finishes.
Larger dormers or ones that include a full bathroom will cost more. Custom windows, vaulted ceilings, or high-end flooring also add to the budget. But compared to moving or building a full addition, it’s one of the most affordable ways to gain real living space.
We give you a clear estimate up front so there’s no guessing. And we don’t inflate numbers just to come in “under budget” later. You’ll know what it costs and what’s included before we start.
Yes. Any structural work that changes your roofline or adds square footage requires a building permit from the Town of Oyster Bay. That includes dormers.
We handle the permit process for you. We submit the plans, coordinate with the building department, and schedule inspections. You don’t have to take time off work or figure out what forms to fill out.
Skipping permits might seem easier, but it creates problems down the road when you sell or refinance. Unpermitted work shows up in appraisals and home inspections, and it can kill a sale or force you to rip things out. We do it right the first time so you never have to worry about it.
Most dormer projects take three to five weeks from start to finish, depending on size and weather. Smaller dormers that don’t include plumbing or major electrical work can be faster. Larger ones with bathrooms or custom features take a bit longer.
We give you a realistic timeline before we start, and we update you if anything changes. Weather delays happen, especially in winter, but we don’t drag jobs out or disappear for days at a time.
The goal is to get you back to normal life as quickly as possible without rushing the work. You’ll have a finished, usable space that’s done right—not a half-done project that sits for months.
Not if it’s insulated correctly. We insulate dormer walls and ceilings to current Long Island building standards, which means R-30 or higher depending on the application. That keeps the space comfortable year-round and prevents your heating and cooling costs from spiking.
We also make sure the dormer is properly ventilated and sealed. Poor ventilation traps heat and moisture, which leads to mold and ice dams in winter. We install ridge vents, soffit vents, or both to keep air moving and temperatures stable.
If you’re adding HVAC to the new space, we coordinate with your system to make sure it’s sized right. A properly built dormer shouldn’t feel like a separate part of the house. It should feel like the rest of your home—just with better light and more headroom.
A shed dormer has a single sloped roof that runs parallel to the main roofline. It’s wider and adds more interior space, which makes it a good choice if you’re trying to create a full bedroom or bathroom. Shed dormers also tend to cost less per square foot because the framing is simpler.
A gable dormer has a peaked roof that sticks out from the main roof. It’s narrower and adds less square footage, but it brings in a lot of natural light and can improve your home’s curb appeal. Gable dormers work well if you just need a little extra headroom or want to brighten up a specific area.
We’ll walk you through both options and show you what makes sense for your roof pitch, your budget, and the look you’re going for. There’s no one-size-fits-all answer. It depends on what you’re trying to accomplish and how your house is built.
Yes. A lot of homeowners use dormer space to add a master bathroom, a second full bath, or a walk-in closet. As long as there’s room to run plumbing and meet code clearances, it’s doable.
Bathrooms require venting, proper drainage, and sometimes upgrades to your existing plumbing. We coordinate all of that. If your home’s plumbing is older, we’ll let you know up front if anything needs to be updated to support the new fixtures.
Closets are even easier. We can frame out a walk-in, add built-in shelving, or just create a standard reach-in closet depending on your layout. The key is planning it right from the start so the space works the way you need it to—not just adding square footage for the sake of it.
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