Replace Your Flat Roof Skylight Window
You’re lying in bed during a heavy Brooklyn rain, listening to water drum against your window-but instead of peaceful, the sound feels threatening. You’re watching a brown stain spread across the ceiling around your skylight, or worse, feeling cold drops hit your face. That’s the moment most people realize their flat roof skylight needs more than another tube of caulk. A proper flat roof skylight replacement fixes the leak, stops the drafts, and gives you back a bright room instead of one you avoid looking up in.
At a certain point, replacing your flat roof skylight window is safer, drier, and usually more cost‑effective than sealing it for the fifth time. Brooklyn wind, snow, and freeze-thaw cycles will keep testing every weak point in that opening until it fails completely.
When a Flat Roof Skylight Needs More Than Another Patch
If you’re seeing any of this, it’s time to look at replacement:
- Water stains or active drips around or under the skylight
- Cracked, yellowed, or brittle plastic dome
- Condensation or permanent fogging between glass panes
- Cold drafts in winter, hot sun baking the room in summer
- Previous repairs that never seem to last more than a season
On a Park Slope duplex last winter, I met a homeowner who’d had three different handymen try to seal a 20-year-old acrylic dome. Each time it lasted maybe four months. The problem wasn’t the sealant-it was that the curb underneath had rotted to the point where there was nothing solid left to seal to. Once we replaced the curb and installed a modern double-glazed unit, the leak stopped and the bedroom finally stayed warm.
Quick Check: Repair or Full Flat Roof Skylight Replacement?
Answer these 4 questions to figure out urgency:
- Is water actively leaking when it rains or snows?
- Is the skylight frame or curb visibly rotten, rusted, or soft when you press on it?
- Is the skylight older than 15-20 years or original to the house?
- Has more than one roofer already tried to fix it with sealant or flashing?
3-4 yes answers: Replacement is almost always the right move. The unit and curb are likely at the end of their life.
1-2 yes answers: You may have a flashing or small component issue, but replacement should still be priced as an option.
0 yes answers, just cosmetic issues: You might be able to wait, but upgrading could improve comfort, light, and energy performance.
What You’re Really Replacing on a Flat Roof Skylight
A skylight isn’t just the piece of glass or plastic you see from inside. Four parts work together on a flat roof skylight:
- Skylight unit: The visible window or dome-glass or plastic-that lets light in. This can be fixed or operable (venting).
- Curb: The raised box that the skylight sits on. It lifts the opening above the roof surface and provides something solid to flash to.
- Flashing system: Metal and membrane pieces that seal the curb into the flat roof and direct water away.
- Roof membrane around the skylight: The EPDM, TPO, modified bitumen, or other roofing material tying the whole system into the rest of the flat roof.
On a Brooklyn flat roof, a “skylight replacement” often includes rebuilding or replacing the curb and redoing the flashing, not just swapping the window. That’s how you stop leaks for good instead of for a few months. If someone quotes you $600 for a skylight replacement and says they’ll be done in two hours, they’re probably just setting a new dome on top of the old, rotting curb-and you’ll be calling someone else in six months.
Types of Flat Roof Skylight Replacements You Can Choose From
| Type | Best for | Key benefits | Things to watch |
|---|---|---|---|
| Fixed, double- or triple-glazed flat skylight | Rooms that just need light, not ventilation (hallways, stairwells, some kitchens) | Simple, fewer moving parts, better energy performance than old domes | Must be flashed correctly to the flat roof material or it will leak at the curb |
| Venting skylight (manual or electric) | Kitchens, bathrooms, or top-floor spaces that get stuffy | Lets heat escape in summer, can reduce moisture build-up | Needs weathertight seals and good controls; more moving parts to maintain |
| Dome-style skylight (acrylic or polycarbonate) | Utility areas, stairwells, or buildings where budget is tight | Lightweight, can shed water and snow well on flat roofs | Cheaper domes can yellow, crack, or become brittle in NYC sun over time |
| Curb-mounted vs. deck-mounted systems | Matching existing conditions and roof build-up height | Curb-mounted units are often better on true flat roofs with thicker membranes and insulation | Curb height must meet code for snow and water; too low is a major leak risk |
Flat Roof Skylights in Brooklyn: Local Issues to Consider
Common Brooklyn conditions that affect your skylight:
- Older brownstones and rowhouses with multiple roof layers and aging curbs
- Top-floor apartments where condensation and interior humidity are already high
- Snow accumulation and ice around skylight curbs in winter
- Tree debris and soot that can stain glass or clog drainage around the curb
- Shared roofs or walkable roofs where people step near skylights
On a Bushwick loft conversion, the owner wanted to replace a big, fogged acrylic dome that was original to the building-probably installed in the 1980s. The problem was that three different roofing layers had been added around it over the years, and the curb was only about 3 inches tall, which is nowhere near high enough for Brooklyn snow and ponding water. We stripped everything back, rebuilt the curb to 8 inches, installed a modern flat glass skylight with Low‑E coating, and tied the flashing into a fresh TPO membrane. The room stayed 6-8 degrees cooler in summer and the owner stopped worrying every time it rained.
How Flat Roof Skylight Replacement Actually Happens
1. Inspection and measurement: We examine the existing skylight, curb, and surrounding roof membrane from the roof and from inside. Exact opening size, roof type, and pitch (even on “flat” roofs) are measured so the new unit fits correctly.
2. Choose replacement unit and schedule: You select the skylight type (fixed or venting, glass or dome). We time the job to avoid forecasted rain because the roof will be briefly open.
3. Protect the interior: Floors and furniture below the skylight opening are covered. In occupied Brooklyn apartments, we coordinate access times with owners or tenants.
4. Remove the old skylight and curb (if needed): The old unit is taken out, sealants and flashing are cut back, and any rotten or rusted curb or decking is removed so we’re working with solid structure.
5. Rebuild curb and integrate with flat roof: We build or adjust the curb to proper height and size, then wrap and flash it into the existing roof membrane using manufacturer-approved details for EPDM, TPO, modified bitumen, or other systems.
6. Install the new skylight unit: The new window is mounted to the curb, sealed, and fastened per specifications. Any required interior trim adjustments are noted.
7. Water test and clean up: Where safe and practical, we perform a controlled water test around the skylight. Debris is removed from the roof, and interior protection is taken up.
What Goes Wrong When Flat Roof Skylights Are Replaced Incorrectly
Shortcuts that cause long-term problems:
- Setting a new skylight on a rotten or too‑low curb: Leaks at the curb, water and snow piling up against the frame, interior damage.
- Relying on caulk instead of proper flashing into the membrane: Sealant cracks in sun and cold; leaks return in the next heavy rain or freeze-thaw cycle.
- Mixing incompatible roof materials at the curb: Poor adhesion and seams that peel, especially where old asphalt meets newer single‑ply membranes.
- Installing a deck‑mounted unit where a curb‑mounted unit is needed: Difficult or impossible to flash correctly, especially with thick insulation or multiple roof layers.
One red flag to watch for: if a contractor says they can replace your skylight without touching the roof membrane or curb, they’re planning to set a new unit on top of an existing, failing system. That’s not a replacement-it’s a temporary bandage that will cost you more in the long run.
Light, Comfort, and Energy: Upgrades to Consider When You Replace
Smart upgrades many Brooklyn owners choose:
- Low‑E and argon-filled glass to cut heat loss in winter and heat gain in summer
- Laminated inner glass for extra safety and sound reduction
- Tinted or solar-control glazing for very bright exposures
- Built‑in blinds or shades on certain skylight models
- Electric venting units with rain sensors for kitchens or bathrooms
If your old skylight was a thin acrylic dome, a modern, insulated flat skylight can make the room feel less drafty, reduce street noise, and tame harsh midday sun-all while solving the leak problem. Not just dry, but actually comfortable.
Can You Replace a Flat Roof Skylight Yourself?
Generally safe for owners or supers:
- Cleaning dirt and debris from glass or dome surfaces from inside
- Checking for visible cracks, gaps, or damaged interior trim
- Photographing leaks and stains to document changes over time
Jobs for a flat roof skylight specialist:
- Removing existing skylights, curbs, or roof membrane
- Rebuilding curbs and flashing into EPDM, TPO, or modified roofs
- Installing new units on roofs with multiple layers or structural concerns
- Working near roof edges or on surfaces without railings or fall protection
Old domes and glass units can crack or collapse if stepped on or leaned on. We regularly see damage from people using skylights as stepping stones on walkable roofs-which is one more reason to let trained crews handle replacement.
How Long Flat Roof Skylight Replacement Takes and What to Expect
Typical timing for one skylight replacement:
- Initial inspection and measurements: 30-60 minutes on site
- Ordering the skylight: from a couple of days to a few weeks depending on model and size
- On-site replacement work: often completed in one day for a straightforward job
What happens inside your home or apartment:
- We protect floors and furniture under the skylight opening
- You’ll hear some noise during demolition and installation
- In most cases, you can stay in the home; we coordinate with you or tenants on timing
Flat Roof Skylight Replacement FAQs for Brooklyn Owners
Do I need to replace the roof around the skylight at the same time?
Not necessarily. If the surrounding flat roof is in good condition and still within its expected life, we can often tie a new skylight and curb into the existing membrane. If the roof is old or already failing, it can be smarter to combine skylight replacement with a reroof so you’re not re-doing work twice.
Can you replace just the skylight dome or glass and keep the curb?
Sometimes. If the curb is sound, at the right height, and properly integrated with the roof membrane, we may be able to install a new unit on the existing curb. But if the curb is too low, rotten, or poorly flashed, we recommend starting fresh.
Will a new skylight stop condensation and fogging?
A modern, insulated skylight helps a lot, but interior humidity also matters. Bathrooms, kitchens, and top-floor apartments may still need good ventilation and exhaust fans to keep moisture under control.
Do skylight replacements in Brooklyn need permits?
Simple one-for-one replacements at the same size and location often do not require a full building permit, but rules can vary based on building type and scope. When curb work, structural changes, or larger openings are involved, filings may be needed. We can advise based on your specific situation.
What if my flat roof is shared with another unit or building?
In many Brooklyn co‑ops, condos, and multi‑family buildings, you’ll need building management or board approval. We can provide photos, specs, and scope descriptions to help you get that approval before work starts.
Get Professional Flat Roof Skylight Replacement in Brooklyn, NY
Stop living with a leaky or cloudy skylight. FlatTop Brooklyn provides:
- On-roof and interior inspection of your existing skylight and curb
- Straightforward explanation of repair vs. replacement options
- Replacement skylight recommendations suited to Brooklyn’s weather and your flat roof system
We regularly coordinate with Brooklyn landlords, co‑op boards, and property managers to replace flat roof skylight windows with minimal disruption to residents and businesses. Request a skylight replacement visit and get a clear plan to fix the problem correctly.