Sarnafil G410-EL Ballasted Inverted Roof System

Sarnafil G410-EL Ballasted Inverted Roof System

Sika Sarnafil Third party certifications:
  • BBA Agrément Certificate

    BBA Agrément Certificate

    Certificate type

PVC-P single-ply system for ballasted inverted roofs.

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PVC-P single-ply system for ballasted inverted roof systems.

System includes:

  • Paving or stone ballast (supplied by others).
  • S-Felt VS 140 filter layer.
  • SarnaTherm XPS insulation.
  • Sarnafil G410-EL waterproof membrane.
  • Sarnafil Type A or Type T fleece as cushion layer on suitable deck.

- Filter layer:

A 140 g/m² polypropylene based fleece, grey in colour, suitable for use as an inverted roof filter layer in loose laid ballasted systems. Sarnafil Type VS is UV stabilised and can be left exposed to weather.

- Insulation:

Unfaced extruded polystyrene CFC and HCFC free thermoset cellular plastic insulant, with a rigid closed cell structure. SarnaTherm XPS is manufactured to BS EN 13164 'Thermal Insulation products for buildings - factory made extruded polystyrene foam (XPS)'.

- Waterproof membrane:

Sarnafil G membranes are manufactured using a state of the art extrusion coating process that eliminates shrinkage and plastic memory and produces a dynamically stable membrane. In the coating process, a glass fibre carrier is coated on both sides with liquid Plastisol, prior to the application of a lacquer coating on the upper surface and laser marking of the membrane surface for identification. The unique lacquer coating eliminates the need for biocides, provides the membrane with an easy to clean surface and prolongs the life of the membrane by reducing plasticiser loss.

The process enables between 2% and 5% of recycled material to be used in the production of new membranes.

- Fleece (cushion layer):

A polypropylene fleece used either as a protective layer below the waterproof liner or as a protective layer on top of the liner.

  • Sarnafil Type A: Is not UV stabilised and must not be subjected to external weather conditions for prolonged periods of time.
  • Sarnafil Type T: UV stabilised, can be left exposed to weathering.


Certified by BBA, in their opinion, to have a "life expectancy in excess of 40 years" for exposed applications, with periodic maintenance as stated below.

A planned maintenance cycle, including inspections by the Certificate holder at minimum intervals of five years, should be introduced if an extended service life is required. The Certificate holder can advise on methods of extending the service life. This could include the use of thicker membranes, specific maintenance requirements or localised replacement and repair.

Should the maintenance cycle not be followed Saranfil G/S membranes have been given by the BBA a life expectancy of 'in excess of 35 years'.


- Filter layer:

Sarnafil Type VS is loose laid, with 300 mm side and end laps.

- Insulation:

The insulation is to be laid loose, with boards lightly butt jointed and level. The specified ballast should be installed as soon as possible, once the filter layer is laid. Until the ballast is laid, the loose laid insulation will be vulnerable to wind uplift forces. If it is necessary to delay ballasting the roof, then temporary ballast, such as bagged gravel or sand, should be strategically placed across the completed roof areas.

Project specific fixing details must be ascertained from the latest Sarnafil project specification.

- Waterproof membrane:

In inverted ballasted applications the G410-EL membrane is generally loose laid, with all overlapping joints hot air welded prior to the application of a protection/ filter fleece and the chosen ballast system. Installation is carried out by Sarnafil trained contractors.

- Fleece (cushion layer):

Sarnafil Type A and Type T:

Sarnafil Type A and Type T are generally loose laid, but can be partially bonded to the substrate with Sarnacol 2170 or Sanracol 2172 if required. In either application, all edges must be overlapped by at least 100 mm.

General information

Uniclass 2015

Ss_30_40_30_79 Single layer sheet inverted roof covering systemsPrimary


J42/120 Inverted roof covering

Specification data - Single layer sheet inverted roof covering systems

Product Reference

Sarnafil G410-EL Ballasted Inverted Roof System


Not required

Primer 110




SarnaTherm XPS insulation


Loose Laid

Waterproof membrane



Sarnafil G410-EL


1.5 mm

1.8 mm


Copper Patina Green

Lead grey

Light grey

White RAL 9016 SR (solar reflective)


Loose laid

Fleece (cushion layer)

Sarnafil Type A

Sarnafil Type T

Filter layer

S-Felt VS 140


Double L rainwater outlets

G/S rainwater outlets

Sarnafil Constant Force post

Sarnafil heat weldable lightning conductor clips


Sarnaplast 2235

Standard product features

Filter layer:

  • Thickness: 0.5 mm.
  • Roll size (w x l): 2 x 50 m.


- Performance:

  • Thermal conductivity: 0.029W/m²K (thicknesses < 120 mm).
  • 0.031W/m2K (thicknesses > 120 mm).
  • CFC/ HCFC free.
  • Zero ODP (Ozone Depletion Potential).
  • Typical Density of 33 kg/m³.
  • Compressive strength 300-500 kPa at 10% deformation.
  • Withstands freeze/ thaw cycling.
  • Closed cell structure minimises water absorption.

Waterproof membrane:

- Width:

2.0 m.

- Length of roll:

20 m (15 m for 1.8 mm thick membrane).

- Weight:

  • 1.5 mm thick: 1.90 kg/m².
  • 1.8 mm thick: 2.30 kg/m².

Fleece (cushion layer):

  • Size: 2 x 50 m.
  • Weight: 300 g/m².

Product Options

Waterproof membrane:

- Colour:

Available in standard colours. Other Colours may be available, subject to a lead time and minimum order quantities.


- Thickness:

Consult Sika Sarnafil for recommendations and details.


  • Double L rainwater outlets: Insulated outlets.
  • G/S rainwater outlets: Injection moulded PVC outlets and scuppers.
  • Primer 110: Surface primer creating a key for Sarnaplast 2235.
  • Sarnafil Constant Force post: Cable-based fall arrest and restraint system.
  • Sarnafil Double L: High drainage capacity insulated rainwater outlet.
  • Sarnafil heat weldable lightning conductor clips.
  • Sarnametal: Galvanized metal sheet with Sarnafil G410-12EL factory laminated to it, for use in prefabricate flashings and drip details.
  • Sarnaplast 2235: Elastic one-part silicone sealant for sealing edges and perimeter upstand flashing terminations.

Third party certifications
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