Sika® Corporation - Roofing -Green Roof Systems


Sometimes called vegetated roofs, eco roofs, or living roofs, green roofs offer a number of sustainable advantages on an otherwise empty, unused space.

Category: PVC membrane roofing | PVC roofing | green roof assembly...

MasterFormat: Membrane Roofing | Thermoplastic Membrane Roofing | Polyvinyl-Chloride Roofing...

Sika® Corporation - Roofing
100 Dan Road
Canton, MA 02021
Tel: (800) 451-2504

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Green Roof Systems


Sometimes called vegetated roofs, eco roofs, or living roofs, green roofs offer a number of sustainable advantages on an otherwise empty, unused space. Depending on load capabilities and other application-driven requirements of your building’s roof, green roofs can be planted with herbs, grasses, flowers, even trees, in an exciting variety of colors, textures, scents and heights. Patios and walkways can become a useable part of the roof environment. No matter what the design, vegetated roofs offer many social, environmental and economic benefits.

  • Storm Water Retention: Green roofs greatly lessen erosion and storm water burden on sewer systems
  • Reduction in Energy Consumption: Green roofs can reduce peak energy demand by lowering a building’s heating and cooling costs
  • Reduction in the Urban Heat Island Effect: Dark roofs hold onto the heat while plants naturally cool their surrounding environments
  • Waterproofing Membrane Protection: A green roof protects the waterproofing membrane from damaging UV rays and freeze-thaw cycling, extending its lifespan
  • Improved Air Quality: Green roofs filter air and produce oxygen
  • LEED and Green Globes: Green roofs contribute to certification within these programs
  • Sound Insulation: Soil and plants can be great sound insulators
  • Aesthetics: Green roofs are visually stimulating and can make great areas for recreation and pleasure
  • Increased Property Value: Installing a green roof can increase property value by providing a valuable building asset

When your building demands absolute system integrity with maximum watertight security, Sika Sarnafil’s self-adhered waterproofing system is for you. The system uses the robust Sarnafil G 476 Self-Adhered (SA) membrane - a composite sheet comprised of the heat-weldable G 476 waterproofing membrane with a closed-cell foam backing. The foam backing is factory-coated with a pressure sensitive adhesive and is protected by a plastic release liner which is removed during installation.

Sarnafil G 476 SA combines the time-tested, proven performance of Sarnafil G 476 waterproofing membrane with the added security of an adhered sheet system. G 476 SA provides peace of mind for specifiers and owners who value the benefits of an adhered system and thermoplastic technology.

The flexible foam backing layer conforms to minor irregularities in the substrate and provides a cushion for the G476 waterproofing membrane. The pressure sensitive adhesive provides a tenacious bond to the substrate mitigating potential water migration under the membrane. The integration of G 476 membrane with a foam backing layer and pressure sensitive adhesive eliminates the need for a field installed separation layer and adhesives. This ‘all-in-one’ product increases applicator productivity and helps keep the project on schedule. Sarnafil G 476 SA also doesn’t require hot asphalt kettles or flammable adhesives, improving worker and job site safety.

Sarnafil G 476 SA is best suited for new construction. It can also be used on certain renovation projects where the old waterproofing system can be removed, or where a new concrete topping slab is placed over the structural deck.


  • Robust, factory-manufactured composite sheet
  • Conforms to minor surface irregularities and mitigates water migration under the sheet
  • Improved applicator productivity and job site safety
  • Growth medium 6 or more inches
  • Heavier weight over 35 lbs/sf
  • Trees, shrubs, gardens, and more
  • Higher maintenance
  • Irrigation usually necessary
  • Designed for human recreation
  • Only used on low slopes
  • Proven Sarnafil membrane
  • Obtain “green building” credits
  • Aesthetically pleasing

The most common design approach over a metal deck is to build a ‘conventional’ loose-laid roof assembly under the vegetated cover.

The rigid insulation material is typically extruded polystyrene (XPS), which is resistant to moisture absorption and has been used in green roof applications for decades. It is available in 40 psi, 60 psi, and 100 psi compressive strengths so it will not crush during construction or under load after placement of the vegetated cover.

Local building codes usually require the installation of a rigid, fire-tested thermal barrier over the metal deck prior to installing the XPS insulation board. A separation felt is installed over the XPS prior to installing the waterproofing membrane.

Rigid isocyanurate foam insulation may be used in this configuration. The benefit is it does not require a thermal barrier. However, since isocyanurate foam is typically manufactured with a 20 or 25 psi compressive strength, rigid hardboard should be installed over the isocyanurate insulation to protect it from damage and potential long-term creep from the weight of the vegetated cover. The Sarnafil G 476 waterproofing membrane is installed over the hardboard.

Both XPS and isocyanurate insulation are available in tapered designs to enhance drainage.

After the Sarnafil G 476 is installed, it is covered by a drainage composite followed by the vegetated cover.


  • Insulation is protected from the elements
  • Insulation will not float since it is under the waterproofing membrane
  • Allows the designer to create slope in the roof assembly
  • Growth medium 1- 6 inches
  • Lightweight 12-35 lbs/sf
  • Low growing plants
  • Low maintenance
  • Low water requirements
  • Usually non-accessible
  • Slopes up to 30 degrees
  • Proven Sarnafil membrane
  • Obtain “green building” credits
  • Aesthetically pleasing

Sika’s G476 waterproofing membrane is specially designed for sub-grade environments. The G476 membrane is available in a range of thicknesses to match your application, overburden type and specific project requirements. Highly puncture resistant, its bright orange color makes it easy to identify and inspect to maintain high levels of quality assurance and control during installation.


Many waterproofing membranes are not resistant to root penetration. They fail due to root infiltration into the field seams and flashings. Sarnafil membranes are inherently root and algae resistant and require no additional barriers to be added to the system. Sarnafil membranes have passed the most stringent European tests for root resistance including both the German FLL and the Swiss SIA 280 standards. The FLL standard test exposes the waterproofing membranes to 4 years of accelerated root growth.


Faulty seams and details are a common source of leaks in green roofs. Some waterproofing membranes use sealants, adhesives or tapes to secure the seams, but because the Sarnafil membrane is thermoplastic, seams and flashings are welded together using Sika’s automatic hot-air welder, the Sarnamatic. When welded together, the sheets become one monolithic layer of material impervious to moisture infiltration.


Sika Sarnafil has established partnerships with leading full-service green roof installers and can provide customers with the advantages of a 'single source' project delivery solution, backed by a 'single source' Sika Sarnafil warranty that includes the vegetated cover and the Sarnafil waterproofing system.

Sika offers several types of warranties including 5, 10, 15 and 20 year durations:

  • Waterproofing Membrane only
  • Waterproofing Labor and Material (System)
  • Single-Source warranty

**Sika offers a single-source warranty for extensive green roof assemblies that includes overburden removal, waterproofing and vegetated cover.

Proven Performance
  • An industry veteran, Sika has produced more than 15 billion sq. ft. of membrane worldwide
  • Leader in thermoplastic membrane manufacturing expertise with more than 50 years of production history.
  • Material that consistently ranks as the highest quality thermoplastic membrane in independent testing

Watertight Integrity
  • Permanent watertight flashings and details with hot-air welded seams and flashings
  • The G 476 membrane is designed for sub-grade environments such as constant dampness, ponding water, high and low alkaline conditions, exposure to plant roots, fungi and bacterial organisms
  • Proven Materials: The Sika manufacturing process uses only the highest quality materials to produce a monolithic, nonlaminated membrane that offers excellent waterproofing and dimensional stability
  • Expert Assistance: We’re involved at each major milestone, offering design assistance to architects and specifiers if needed
  • Skillful Workmanship: We sell directly to a select group of trained, authorized applicators - only the best are invited to join our team.

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