Roof Insulation & Tapered Systems
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Learn moreGreen roofs for New York, NY buildings, built on the right membrane
A green roof is only as good as the roof under it. We build the waterproofing, root barrier and drainage first, then the tray or built-in-place green roof on top.
- We answer 24/7
- Tray and built-in-place
- Membrane built first
Quick answer: A green roof in New York, NY is a layered system over a waterproof roof: root barrier, drainage and retention layer, filter fabric, lightweight growing medium, and hardy plants such as sedum. It can cover the city's sustainable roofing zone on a full replacement, alone or with solar, if the structure can carry the weight.
What the job involves
What goes into a green roof
Most city green roofs are extensive systems: a few inches of engineered growing medium planted with hardy sedums that need little water or care. The plants sit on a drainage and retention layer, over a root barrier, over the roofing membrane itself.
Two things decide whether it works. The membrane underneath has to be sound and flood tested before anything goes on top, because finding a leak later means lifting the garden. And the structure has to carry the saturated weight of the system, which an engineer confirms before design.
Your options
Green roof, solar, or both?
| Option | Good for | Keep in mind |
|---|---|---|
| Green roof | Shaded roofs, and owners who want stormwater retained on the roof. | Needs structure for the saturated weight, and periodic maintenance. |
| Solar | Sunny roofs with clear, open area. | Racking has to be flashed or ballasted without damaging the new membrane. |
| Both | Roofs that are partly shaded and partly clear. | Fire access paths still have to be kept clear across the roof. |
Cost factors
What a green roof costs depends on
System type
Trays and built-in-place systems differ in material and labor.
Depth of growing medium
Deeper systems weigh more and cost more.
Structural review
An engineer confirms the building can carry the load.
Membrane and root barrier
The waterproofing under the garden has to be right first.
Hoisting
Getting growing medium and trays onto a city roof can mean a crane.
Establishment and upkeep
Watering while plants take hold, then periodic care.
Variations of the job
Green roof options we install
Sustainable roofing zone
When a full roof replacement triggers the requirement, a green roof, solar, or a mix can cover the zone. The qualifying area is worked out with the building's design professional before a system is chosen.
Tray systems
Pre-planted modules that lock together on the roof. Quick to install and easy to lift for membrane access, which makes them a sensible choice where the roof will need future work.
Built-in-place systems
Drainage, fabric, growing medium and plants installed as continuous layers. More flexible around odd shapes and tight corners, but slower to install and harder to lift later.
Local conditions
When the sustainable roofing zone applies
Since November 15, 2019, New York City has required a sustainable roofing zone, meaning solar, a green roof or both, on new buildings and on existing buildings replacing an entire roof deck or roof assembly, with equipment areas, fire access paths and parapets excluded. For a building that cannot fit much solar, a green roof is often how the zone gets covered. It is planned with the replacement, not added afterwards.
What is included
What a green roof proposal should cover
- Structural load review by an engineer
- Sustainable roofing zone area worked out with your design professional
- Membrane type and a flood test before the garden goes on
- Root barrier
- Drainage and retention layer
- Vegetation-free zones at drains, edges and equipment
- Growing medium depth and saturated weight
- Plants suited to a hot, windy roof
- Establishment watering and a maintenance plan
How it runs
How a green roof goes in
- 1
Structure and zone
Engineer's load check and the sustainable roofing zone layout.
- 2
Waterproofing
New membrane with root barrier, flood tested before anything covers it.
- 3
Drainage layer
Retention and drainage board, with clear zones kept at the drains.
- 4
Growing medium and plants
Trays set or layers built, then planted.
- 5
Establish and maintain
Watering while plants take hold, then seasonal visits.
Questions we hear
Green roof questions
Not if the membrane under it is sound and flood tested before the garden goes on. Most green roof leaks trace back to membrane work done before the plants, or to drains buried under growing medium.
Watering while it establishes, then a few visits a year to weed, clear drains and check coverage. Sedum roofs are low-maintenance, not no-maintenance.
That is an engineer's call. Shallow sedum systems are the lightest, but even they weigh a lot when saturated, so the structure is checked before design.
Yes. A green roof, solar, or a combination are the ways the zone can be covered. Sun, structure and budget decide which fits.
Only if the existing membrane is sound and suitable, usually with a new root barrier. Older roofs are often better replaced first, since the garden will sit on them for years.
Related services
Related roofing work
Flat Roof Repair
Blisters, split seams, punctures and cracked surfacing repaired with materials that match the membrane already on your roof.
Learn moreFlat Roof Replacement
Tear-off or recover, new insulation, new flashings and drains, with the DOB filing and the sustainable-roof question settled before work starts.
Learn morePlanning a green roof?
Call and we will plan the waterproofing and the garden as one roof.