Parapet flashing
The membrane runs up the wall and tucks under the coping.
Flat Roofers NY · Queens
Concrete Flat Roof Material for Queens Buildings
Concrete flat roof material, installed by Flat Roofers NY, is a fully adhered waterproofing membrane bonded straight to your concrete roof deck. We put it down on Queens buildings every week.
Want the slab checked first? The estimate is free.
Material comparison
The materials that go on a concrete roof
Four systems bond well to a slab. Here's how they compare.
| System | Our usual pick Modified bitumenTorch-down | TPOSingle-ply sheet | EPDMRubber sheet | Liquid-appliedPolyurethane or elastomeric |
|---|---|---|---|---|
| How it bonds | Asphalt primer, then torched on | Primed deck, bonding adhesive | Bonding adhesive over cover board | Primer, then cures onto the surface |
| How long it lasts | 20 to 25years | 20 to 30years | 25 to 30years | 10 to 20years, recoatable |
| Suits best | Pavers and terraces | Big open roofs | Ponding-prone decks | Foot traffic, crowded decks |
Cementitious waterproofing under roof pavers is a fifth route. Got torch-down that's mostly sound? Patching the bitumen layer you already have can beat a tear-off.
Slab prep
What your slab needs before the material goes down
No membrane outlasts the concrete under it.
So we fix the deck first.
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Ponding water
Calls for tapered insulation and drain repair. See how we clear standing water before the new roof goes on.
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Cracks
Routed out, filled and sealed so they don't show through.
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Spalling and exposed rebar
Spall repair comes before any membrane. Loose concrete out, rebar cleaned and coated, then patched.
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Moisture in the slab
We run a moisture survey. Water already dripping inside? Then the leak gets stopped first.
How it's built
How we build it up, layer by layer
First day on the roof, we grind and sweep the deck clean. Then we prime it so the adhesive grabs the concrete. After that the system goes on in order:
- Concrete deck, repaired and dry
- Primer for adhesion
- Tapered insulation, wherever drainage needs pitch
- Cover board
- Fully adhered membrane on top
Roof section · slab up
Edge details
Where concrete roofs fail: the edges we detail
Leaks start at edges and openings. That's where we slow down.
Roof drains
Sealed into the drain bowl under a new clamping ring.
Scuppers
Lined in metal, then stripped in with extra plies.
Expansion joints
A raised curb with a flexible cover that moves with the building.
Why it matters
Why a concrete roof needs a membrane at all
Concrete isn't waterproof. Rain soaks in, freezes and cracks the slab. Once water reaches the rebar, the steel rusts, swells and pops chunks off.
Put a membrane on top and that cycle stops. Your top floor stays dry. The slab stays dry too, and the roof can last decades longer.
Buildings we cover
The concrete roofs we cover in Queens
Apartment buildings, co-ops and condos, mixed-use buildings, attached houses, commercial buildings, churches and warehouses. Parking decks get a traffic-grade deck coating built for tires.
Our crew works out of Elmhurst and covers the Queens neighborhoods on our route.
Free estimate
Which material belongs on your concrete deck?
The free estimate starts on your roof, with a look at the slab's condition. Then we tell you which concrete flat roof material fits and what it'll cost.