Flat Roof Scupper Installation Service

A properly sized four-inch scupper can move more than 3,000 gallons of water per hour off a flat roof during a heavy Brooklyn storm-but only if it’s placed at the right height, integrated with the membrane correctly, and discharging to a safe location. That’s the difference between a hole someone punched through a parapet wall and a true scupper installation designed around your building’s drainage system. At FlatTop Brooklyn, we approach scupper work as a precision fix for chronic ponding, overwhelmed internal drains, and parapet overflow that turns facades into waterfalls. We size, locate, and install scuppers based on your roof area, measured slope, parapet condition, and where water can actually go once it leaves the roof-not guesswork.

The Drainage Problems Scuppers Can Solve on Flat Roofs

Most property owners call us about scuppers after they’ve watched the same puddle sit along the parapet for days, or worse, after a storm sent water cascading over the edge and down a neighbor’s wall. Those symptoms point to a flat roof that can’t move water out fast enough-or at all.

If any of this sounds familiar, scupper installation or upgrade may be the answer:

• Water sits along your parapet walls for days after rain instead of leaving the roof.
• During big storms, water spills randomly over the edge instead of through a controlled outlet.
• You see staining, efflorescence, or peeling paint on rear or side walls below the roof edge.
• Neighbors complain about water dumping into their yard or onto shared walkways.
• An existing scupper is tiny, high up on the wall, or half blocked by old patchwork.

The common thread is a drainage system that’s either missing, undersized, or positioned wrong for how water actually behaves on your roof. Scuppers solve these problems by giving water a direct, horizontal path off the roof-but only when they’re engineered to handle the flow your building generates.

Why a Dedicated Scupper Installation Service Matters

You can’t just cut a hole in a parapet and call it a scupper. The opening needs a box or sleeve to control flow, protect the wall structure, and tie into the roof membrane without creating a leak path. The height of that opening sets the waterline for your entire roof-set it too high, and you still get ponding; too low, and you lose your emergency overflow margin.

We treat scupper installation as part of your flat roof’s drainage design. That means inspecting the roof surface, measuring actual slope (not what the drawings say), understanding where existing drains are and whether they’re working, and figuring out where discharged water can safely land. A scupper on the street side might need a leader head and downspout running to grade; one facing a rear yard might spill to a lower roof or a splash block. All of that gets planned before we touch the wall.

On a Cobble Hill three-story last spring, the top-floor roof had two internal drains that were clogged more often than not, and ponding along the south parapet was staining the brick below. We added two 6×4-inch scuppers on that wall, each feeding a new leader head tied to existing downspouts. The key decision was setting scupper invert height one inch above the average roof surface and two inches below the parapet cap, giving water a fast exit while keeping an overflow buffer. That balance-between getting water out and keeping the roof from draining too low-only works when you measure the real roof conditions first.

Scupper 101: What It Is and How It Works on a Flat Roof

What is a scupper? A scupper is an opening through a parapet or roof edge that lets water move horizontally off a flat or low-slope roof. It’s often a metal or molded box that projects through the wall, usually connected to a leader head and downspout or designed to spill into a controlled area. Unlike an internal drain that pulls water down through the roof deck, a scupper works at or near the surface, moving water sideways through the building envelope.

Where scuppers live in your drainage system:

1. Roof surface and slope move water toward the parapet or low edge.
2. Membrane and flashing form a watertight “bowl” up to scupper level.
3. Scuppers form the openings at that bowl’s rim, setting the waterline height.
4. Leaders, downspouts, or splash blocks carry water away from the building.

That sequence matters because a scupper isn’t a standalone fix-it’s the exit point for a roof that’s already directing water toward it. If the roof slopes the wrong way or the membrane isn’t continuous up to the scupper opening, you’ll still have problems even with perfectly sized scuppers.

What Our Flat Roof Scupper Installation Service Includes

From first visit to final test, our scupper installation work covers the full chain-from roof surface to ground discharge. Here’s what that looks like on a typical Brooklyn job:

• On-roof and parapet inspection to understand existing drainage, low spots, and wall condition.
• Sizing and placement plan for new or enlarged scuppers, including any emergency/overflow scuppers.
• Safe creation or enlargement of openings through parapet walls or edge structures.
• Installation of scupper boxes or sleeves compatible with your flat roof membrane.
• Integration of scuppers into the roofing and wall flashings.
• Connection to leader heads, downspouts, or lower roofs, following Brooklyn norms and any code or HOA rules.
• Controlled water test where practical, to verify flow and check for weeping or leaks.

That last step-testing-sounds simple but reveals a lot. We’ll run a hose or buckets of water across the roof and watch how it moves toward the scupper, how fast it exits, and whether the box and flashing stay dry on the underside. On one Park Slope rowhouse, testing showed that a scupper we’d just installed was working fine, but water was also pooling at the opposite corner because the roof slope was flatter than expected. We added a second, smaller scupper there to handle that zone’s runoff, turning a near-miss into a complete drainage solution.

How We Decide Where to Put Scuppers-and How Big They Should Be

Scupper layout starts with math: how much roof area drains toward each parapet section, how much rain Brooklyn gets in a design storm (usually a 15-minute cloudburst), and how fast a given scupper size can move that water. A 4×4-inch scupper opening can handle roughly 400 square feet of roof in a typical Brooklyn storm, assuming decent slope. Double that roof area and you need a bigger opening or a second scupper.

Key factors we consider for each Brooklyn roof:

• Total roof area and which sections will drain toward each parapet wall.
• Existing slope-real, measured slope, not just what drawings say.
• Height and shape of parapets, coping stones, and edge metals.
• Locations of existing internal drains, downspouts, and safe discharge zones.
• Wind exposure, leaf/debris load, and where scuppers are likely to clog.
• Any shared walls or property-line issues with neighbors.

We also design for peak flow, not average rain. A one-inch-per-hour storm might be manageable, but Brooklyn sees two-inch-per-hour bursts several times a year, and that’s when undersized scuppers turn roofs into bathtubs. So we build in headroom-usually 20-30 percent extra capacity-and we locate scuppers at the actual low points, not where it’s convenient to cut the wall.

These numbers assume quarter-inch-per-foot slope and clean scupper throats. Flatter roofs or scuppers prone to leaf blockage need larger openings or more frequent placement. On a Williamsburg mixed-use building with a nearly flat 1,400-square-foot roof, we installed three 6×4 scuppers spaced around the perimeter instead of relying on one big opening, so each parapet wall had its own exit and no single scupper could bottleneck the whole roof.

Tying New Scuppers into Your Existing Flat Roof Membrane

The scupper box is where your roof membrane meets the outside world, and that junction has to be watertight under pressure, freeze-thaw cycles, and years of UV exposure. How we integrate scuppers depends entirely on what’s already on your roof.

EPDM (rubber roofs): We use metal scupper boxes with wide flanges-usually 12 inches or more-so there’s enough surface for adhesive and mechanical attachment. The EPDM gets primed, then fully adhered up to and into the scupper throat. Corners get reinforced with EPDM patches because 90-degree turns are where rubber likes to split under stress. We avoid relying on caulk; the bond between membrane and metal flange does the waterproofing.

TPO and PVC (single-ply thermoplastics): These membranes heat-weld to metal, so we install scupper boxes clad with weldable material or use pre-fabricated TPO/PVC scuppers. The membrane gets welded directly to the scupper flange and, where the design allows, into the throat itself. Outside corners at the parapet base get pre-formed corner pieces that create a continuous, weldable envelope around the scupper. Done right, the weld is stronger than the membrane itself.

Modified bitumen and built-up roofs: These systems use multiple plies, so scupper boxes get embedded into the bitumen or cold adhesive as the cap sheet goes down. We torch or cold-apply layers up and over the flanges, overlapping onto the parapet wall. Timing matters-parapet caps and scupper installation need to happen in sequence so the flashings tie together, not as separate patches that meet at a caulk line.

Why we rarely rely on caulk at the scupper: Sealant has its place for edge details and terminations, but long-term watertightness comes from properly lapped and bonded membranes at the scupper box and wall-not from a heavy bead of caulk that cracks after a couple of Brooklyn winters. If your scupper’s waterproofing depends on caulk staying perfect, it’s not detailed correctly.

Working Safely in Parapet Walls and Facades

Scuppers depend on the wall they pass through. The masonry or framing around that opening must be solid, or cracks and voids become leak paths. Older Brooklyn parapets-especially on pre-war rowhouses-often need local rebuilding, repointing, or replacement of rotted wood blocking before new scuppers can go in safely.

We start by cutting a neat opening at the marked location, using a masonry saw or reciprocating saw depending on wall type. Then we remove any loose or damaged material around the cut edges and rebuild with new brick, block, or framing as needed. If coping stones sit above the scupper, we’ll temporarily remove and reset them, making sure the scupper box doesn’t disrupt the coping’s overhang or drip edge.

Typical parapet-related tasks during scupper installation:

• Careful cutting through brick, block, or framed walls at marked scupper locations.
• Removing loose or damaged masonry, then rebuilding edges with proper support.
• Re-setting or modifying coping stones or metal caps around new openings.
• Parging or lining scupper throats so water flows cleanly and walls are protected.

On a Clinton Hill brownstone with 120-year-old brick parapets, we found that the mortar around our planned scupper location was little more than sand. We ended up rebuilding a two-foot section of that parapet, tying in new brick with stainless pins, before installing the scupper box. That added half a day to the project but meant the scupper was anchored to solid structure, not crumbling masonry that would let water seep back into the wall.

Managing Water After It Leaves the Scupper

A scupper solves your roof’s ponding problem, but it creates a new one if water then dumps onto a sidewalk, a neighbor’s yard, or your own foundation. So discharge planning is part of every scupper job.

Leader head and downspout: This is the classic approach. The scupper pours into a decorative or utilitarian collector box (the leader head), which feeds a vertical downspout running to grade or into an existing drain system. Leader heads also act as overflow protection-if the downspout clogs, water spills out of the open-top head instead of backing up into the scupper and onto the roof. We use this setup on rear yards, side alleys, or any facade where a downspout can run cleanly to a safe discharge point.

Spill to lower roof: When you have multi-level roofs, an upper scupper can discharge onto a lower flat roof that has its own drainage. The key is protecting the lower membrane from concentrated flow and making sure that roof’s drains can handle the extra volume. We’ll typically add a metal splash pan or diverter under the upper scupper so water spreads out instead of hammering one spot on the lower roof.

Controlled splash away from wall: On small roofs over non-sensitive areas-like a garage extension or rear shed roof-a short scupper projection with a diverter can throw water clear of the facade without needing a full downspout. This only works where the ground can absorb or drain the discharge and where neighbors won’t be affected.

Where you can’t send water in Brooklyn: We avoid discharging directly onto neighboring properties, public sidewalks, or areas where water can pool against your own foundation. That’s not just good-neighbor policy; it can keep you out of trouble with the Department of Buildings, co-op boards, and local inspectors who take drainage violations seriously.

What to Expect When You Hire FlatTop Brooklyn for Scupper Installation

Your scupper project moves through four stages, from first call to follow-up inspection:

1. Initial conversation and scheduling: We ask about ponding patterns, any known leaks, building type, and whether you’re dealing with a single-family rowhouse or a multi-tenant property. For co-ops and condos, we coordinate with management or supers to schedule access and understand any facade or architectural restrictions.

2. On-site inspection and proposal: We inspect the roof, parapets, and discharge areas, measure slope and roof sections, and take photos of existing conditions. Then we outline a recommended scupper plan-how many, what size, where they’ll go, and how water will leave the building. The proposal includes a clear scope of work, timeline, and cost breakdown.

3. Installation day(s): Access is set up with scaffolding, ladders, or roof hatches as needed. We complete parapet work first-cutting, rebuilding, and prepping openings-then install scupper boxes, tie into the roof membrane, and attach exterior leaders or splash control. Work areas stay as tidy as the building layout allows, and we haul away all debris at the end of each day.

4. Testing, cleanup, and walkthrough: Where practical, we run water across the roof to verify scupper flow and check for any weeping at flashings. You receive a summary of what was done, installation photos, and maintenance recommendations-usually just an annual check to make sure scupper throats stay clear of leaves and that leader heads aren’t clogged.

What You Can Help With-and What We Handle

Helpful things you can do:

• Describe where water currently ponds or overflows, and how long it sits after rain.
• Share any history of leaks or previous drainage fixes you know about.
• Point out areas where you do or don’t want visible downspouts-especially on street-facing facades.
• Make sure roof access is clear on the scheduled day, and notify tenants or neighbors if we’ll be working near shared walls.

What FlatTop Brooklyn takes care of:

• Measuring slopes, roof areas, and structural conditions that determine scupper design.
• Calculating scupper size, number, and exact locations based on drainage loads.
• Cutting openings, rebuilding parapet edges, and installing scupper boxes with proper flashing.
• Integrating scuppers into the roof membrane system-EPDM, TPO, modified bitumen, or other materials.
• Testing the new drainage paths to confirm flow and verify watertight installation.

Flat Roof Scupper Installation FAQs

Can you add scuppers without replacing my whole flat roof?
Often yes. If the existing membrane and parapets are in fair condition, we can cut in new scuppers, repair surrounding areas, and tie into the current system without a full reroof. If the roof is already at the end of its life-cracking, multiple patches, widespread ponding-we may recommend combining scupper work with a membrane replacement so everything gets a fresh start and a longer warranty.

Will new scuppers stop all leaks along my parapet?
They will reduce standing water and overflow, which cause many parapet leaks. But if the wall itself, the coping stones, or the existing flashings are already compromised, we may also need to repair those as part of the project. A scupper handles drainage; it doesn’t fix a cracked cap or failed wall flashing above the roofline.

Do I need permits to add scuppers in Brooklyn?
Small drainage improvements on existing roofs often fall under minor work that doesn’t require a full permit, but the answer depends on building type, whether you’re in a historic district, and whether any structural changes are involved. We can advise based on your specific property and coordinate with your architect or expeditor when permits are needed.

How long does a scupper installation take?
Simple single-scupper jobs on small roofs-under 500 square feet, straightforward parapet-can often be completed in one day. Larger roofs with multiple scuppers, parapet rebuilding, or complex leader routing can take two to four days. We’ll outline timing along with your proposal so you know what to expect.

Will scuppers make my facade look bad?
They don’t have to. We aim to align scuppers and leaders neatly, use materials that match or complement your building, and coordinate with your facade style. On street-facing elevations we’re especially careful to keep details clean and, where possible, discreet-recessed leader heads, painted downspouts that blend with trim, and scupper boxes sized to the opening without unnecessary bulk.

Schedule Flat Roof Scupper Installation or Evaluation in Brooklyn

Let your flat roof drain the way it was designed to. We offer on-site review of your existing drainage and parapets, custom scupper layout sized for your building and Brooklyn’s storm patterns, and professional installation integrated with your current or new roof system. We’ve installed and rebuilt scuppers on brownstones, rowhouses, and small apartment buildings throughout Brooklyn-from Park Slope to Williamsburg to Crown Heights-and our focus is simple: move water off your roof safely, protect your walls, and keep peace with your neighbors below.

Contact FlatTop Brooklyn to schedule a scupper consultation and get a clear plan for solving your flat roof’s drainage problems.