Hybrid Roofing Systems
By combining characteristics of multiple roofing technologies, hybrid systems can increase the overall robustness of the assembly.
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What is hybrid roofing?
A hybrid roof assembly is where two roofing membranes, composed of different technologies, are used in one roof system.
For example, base layers of asphaltic modified bitumen can be combined with a top layer of reflective single-ply membrane such as a fleece-back TPO or PVC. Together, this system combines the best selected characteristics of both membranes.
Discover how hybrid roofing systems can help enhance energy efficiency, resiliency, and sustainability.
Read moreCombined benefits of multiple technologies
Protection and Durability
Inclusion of a bottom layer of an asphaltic membrane provides redundancy and protection against punctures1, and adds overall thickness to the system.
Increased Solar Reflectance
The addition of a single-ply reflective membrane over a dark-colored asphaltic membrane will greatly increase the Solar Reflectance Index (SRI) of the roof surface.
Versatility
A hybrid roof solution offers the opportunity to select a membrane or cap sheet to addresses specific challenges, including exposure to certain project specific conditions or the need for overburden, and more.
Minimum odor and noise disturbance
The selection of a single ply membrane as the top layer allows for installation with low VOC options that can have minimum odor and noise disturbance if construction is taking place while the building is occupied.
1GAF warranties and guarantees do not provide coverage against hail or other punctures except where additional puncture resistance coverage is purchased on
eligible jobs. Contact GAF for more information. Refer to gaf.com for more information on warranty and
guarantee coverage and restrictions.
Project use cases for hybrid roofing systems
Explore hybrid roofing assembly options²
Cold Applied 9 in OC Base Sheet Fasteners
- Metal Deck
- Lightweight Insulating Concrete (LWIC)
- GAFGLAS® STRATAVENT® Nailable Venting Base Sheet applied with Base Sheet Fasteners at 9 inches OC
- RUBEROID® 20 Smooth Membrane (Asphaltic base sheet with sand top surface) applied in MATRIX™ 102 SBS Membrane Adhesive
- EverGuard® TPO Fleece-back Membrane applied in GAF LRF Adhesive XF spatter pattern
Cold Applied 7 in OC Base Sheet Fasteners
- Metal Deck
- Lightweight Insulating Concrete (LWIC)
- GAFGLAS® STRATAVENT® Nailable Venting Base Sheet applied with Base Sheet Fasteners at 7 inches OC
- RUBEROID® 20 Smooth Membrane (Asphaltic base sheet with sand top surface) applied in MATRIX™ 102 SBS Membrane Adhesive
- EverGuard® TPO Fleece-back Membrane applied in GAF LRF Adhesive XF spatter pattern
Cold Applied 9 in OC Base Sheet Fasteners
- Metal Deck
- Lightweight Insulating Concrete (LWIC)
- GAFGLAS® STRATAVENT® Nailable Venting Base Sheet applied with Base Sheet Fasteners at 9 inches OC
- RUBEROID® 20 Smooth Membrane applied with a torch
- EverGuard® TPO Fleece-back Membrane applied in GAF LRF Adhesive XF spatter pattern
Cold Applied
- Structural Concrete Deck
- MATRIX™ 307 Premium Asphalt Primer
- RUBEROID® 20 Smooth Membrane applied in MATRIX™ 101 Premium SBS Membrane Adhesive
- 1st layer EnergyGuard™ Polyiso Insulation. Ribbon application of OlyBond500™ Adhesive Fastener
- 2nd layer EnergyGuard™ Polyiso Insulation. Ribbon application of OlyBond500™ Adhesive Fastener
- EnergyGuard™ HD Polyiso Cover Board (½”). Ribbon application of OlyBond500™ Adhesive Fastener
- RUBEROID® 20 Smooth Membrane applied in MATRIX™ 101 Premium SBS Membrane Adhesive
- EverGuard® TPO Fleece-back Membrane applied in OlyBond500™ Adhesive Fastener in splatter pattern
Heat Weld Applied
- Structural Concrete Deck
- GAF SA Vapor Retarder XL
- 1st layer EnergyGuard™ Polyiso Insulation. Ribbon application of GAF LRF Adhesive XF
- 2nd layer EnergyGuard™ Polyiso Insulation. Ribbon application of GAF LRF Adhesive XF
- DensDeck® Prime Roof Board (½”). Ribbon application of GAF LRF Adhesive XF
- RUBEROID® 25 Smooth Membrane applied with a torch
- EverGuard® TPO Fleece-back Membrane applied in GAF LRF Adhesive XF in splatter pattern
Hot Asphalt Applied
- Structural Concrete Deck
- MATRIX™ 307 Premium Asphalt Primer
- 1-2 plies of GAFGLAS® Ply 4 applied in hot mopping asphalt
- 1st layer EnergyGuard™ Polyiso Insulation applied in hot mopping asphalt
- 2nd layer EnergyGuard™ Polyiso Insulation applied in hot mopping asphalt
- STRUCTODEK® HD Fiberboard (½”) applied in hot mopping asphalt
- RUBEROID® 20 Smooth Membrane applied in hot mopping asphalt
- EverGuard® TPO Fleece-back Membrane applied in GAF LRF Adhesive XF in splatter pattern
Heat Weld Applied
- Metal Deck
- USG Securock® Brand Gypsum‑Fiber Roof Board (½”)
- GAF SA Vapor Retarder XL
- 2 layers of EnergyGuard™ Polyiso Insulation
- USG Securock® Brand Gypsum‑Fiber Roof Board (½”)
- Drill-Tec™ #12 Fasteners and Drill-Tec™ 3" Steel Plate
- MATRIX™ 307 Premium Asphalt Primer
- RUBEROID® HW Smooth Membrane applied with a torch
- EverGuard® TPO Fleece-back Membrane applied in GAF LRF Adhesive XF
Cold Applied
- Metal Deck
- USG Securock® Brand Gypsum‑Fiber Roof Board (½”)
- GAF SA Vapor Retarder XL
- 2 layers of EnergyGuard™ Polyiso Insulation
- EnergyGuard™ HD Polyiso Cover Board (½”)
- Drill-Tec™ #12 Fasteners and Drill-Tec™ 3" Steel Plate
- RUBEROID® 20 Smooth Membrane
- Applied in MATRIX™ 101 Premium SBS Membrane Adhesive
- EverGuard® TPO Fleece-back Membrane applied in GAF LRF Adhesive XF
Heat Weld Applied
- Metal Deck
- DensDeck® Roof Board (½”)
- GAF SA Vapor Retarder XL
- 2 layers of EnergyGuard™ Polyiso Insulation
- EnergyGuard™ HD Polyiso Cover Board (½”)
- Drill-Tec™ #12 Fasteners and Drill-Tec™ 3" Steel Plate
- MATRIX™ 307 Premium Asphalt Primer
- RUBEROID® HW 25 Smooth Membrane
- Applied with a torch
- EverGuard® TPO Fleece-back Membrane applied in GAF LRF Adhesive XF
Hot Asphalt Applied
- Metal Deck
- 2 layers of EnergyGuard™ Polyiso Insulation
- Drill-Tec™ #12 Fasteners and Drill-Tec™ 3" Steel Plate
- STRUCTODEK® HD Fiberboard (1/2”)applied in hot asphalt
- RUBEROID® HW Smooth Membrane
- Applied in hot asphalt
- EverGuard® TPO Fleece-back Membrane applied in GAF LRF Adhesive XF
2For illustrative purposes only. Refer to application guides for complete system specifications/requirements and application instructions.
Installing multi-ply redundancy in a hybrid roofing assembly
Professional roofing contractors Dave and Wally talk about installing multi-ply redundancy in a hybrid roofing assembly, using low-rise foam to fully adhere fleece-back TPO, PVC or KEE over a modified bitumen base layer.
Documents
PVC/KEE Details
Download PVC detailsHybrid Assembly Details
Download Hybrid Details3 Part Specifications
Download 3 part SpecInstallation Manual
Download Install ManualSee the full hybrid brochure
See brochureTap into GAF professional resources
Design Services
Our regionalized Design Services team collaborates with you to solve challenges, including guidance on product selection, guide specs & assembly letters, LEED® requirements, fastening patterns, sheet layout, and more.
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GAF Building and roofing science team
Book a virtual meeting for advice from trained experts on project-specific questions, code conundrums, and impossible details. Learn more here or email us at buildingscience@gaf.com
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Request a Lunch & Learn
The GAF Lunch & Learn program offers an opportunity for professionals to earn AIA CEU credits while learning about various roofing topics from GAF experts. You can request a session for your office.
Frequently Asked Questions
A hybrid roof assembly can be an attractive solution in re-roof scenarios. In these applications a coverboard is applied over a prepared existing roof substrate. The asphaltic base sheet and subsequent single-ply membrane can be installed on top of the existing roof system without an expensive and disruptive full tear-off of the existing assembly. It is important to ensure there is no moisture present in the old roof assembly and a structural engineer has confirmed the structure of the building can handle the design load of the newly proposed hybrid roof assembly. By adding a single-ply membrane, reflectivity of a new cap membrane will likely increase compared to the existing darker membrane and potentially extend the service life of the roof assembly due to the lower rooftop temperatures and the additional layer of UV protection. Additionally, if construction takes place while the building is occupied, the asphaltic base sheet can be mechanically fastened, with hot air welded seams, and the single-ply membrane can be installed with low VOC options that can cause minimal odor and noise disturbance to the building occupants.
One benefit of a hybrid roof is its versatility. Materials are selected for the incremental benefits they bring to the roof system. As a result, there’s a fairly wide variety of options. However, a typical system may include Ruberoid® SBS modified bitumen base membranes or GAFGLAS® base roofing membrane plies of asphaltic SBS modified bitumen, combined with a top layer of reflective fleece-back EverGuard® TPO, PVC or PVC KEE single-ply membrane. Together, this system combines the best selected performance characteristics of both asphaltic and thermoplastic membranes. The asphaltic base layer provides a strong waterproofing layer and added durability with enhanced elasticity to the total system performance. The cap layer provides UV resistance and an additional waterproofing layer increasing the robustness of the total roofing assembly.
Due to their strong protection against leaks and multi-ply system redundancy, hybrid roof assemblies are a popular choice for performance-sensitive locations such as K-12 & higher education buildings, data centers, hospitals, and other structures where closures and leaks can cause unacceptable disruption.
Are Hybrid Roof Assemblies Worth the Hype?
How can roofing assemblies contribute to a building's energy efficiency, resiliency, and sustainability goals? Intentional material selection will increase the robustness of the assembly including the ability to weather a storm, adequate insulation will assist in maintaining interior temperatures and help save energy, and more durable materials may last longer, resulting in less frequent replacements. Hybrid roof assemblies are the latest roofing trend aimed at contributing to these goals, but is all the hype worth it?
Explore healthcare and hospital roofing solutions
GAF offers a wide range of energy efficient, fully integrated roofing systems that can last a long time, helping protect the health facility’s investment. We also offer restoration and recover solutions to help extend roof life, reducing expense while protecting both the facility’s investment and staff/patient satisfaction.