Waterproofing membrane for mechanically fastened roofs.


A 2 mm thick polyester reinforced, multi-layer, synthetic roof waterproofing sheet based on premium-quality polyvinyl chloride (PVC) containing ultraviolet light stabilizers and flame retardant according to BS EN 13956.

It is a hot air weldable roof membrane formulated for direct exposure and designed for use in all global climatic conditions. The membrane is produced with an integral polyester scrim reinforcement for high strength used within the Sarnafast spot fastening system and Sarnabar linear mechanically fastened system.

Sarnafil S327-EL HD has a unique lacquer coating applied to the top of the membrane to resist staining from airborne dirt and pollutants. The membrane has no built-in stress at the time of production and has a fully encapsulated reinforcement with no risk to delamination or water-wicking. Available in a variety of colours.

Features and benefits:

  • High resistance to weathering, including permanent UV irradiation.
  • Good flexibility in cold temperatures.
  • No built-in stress at the time of production.
  • High dimensional stability.
  • High water vapour permeability.
  • Good weldability.
  • No risk of delamination or water-wicking.
  • Can be produced also in a variety of colours.
  • Lacquer coated surface.
  • Highest reflectance properties for excellent cool roofing characteristics and bifacial photovoltaic panels, e.g. Solyndra (relevant only for colour RAL 9016 SR).
  • Recyclable.
  • CE marked to BS EN 13956, and manufactured in accordance with BS EN ISO 9001 and BS EN ISO 14001.


Waterproofing membrane for mechanically fastened roofs.

General information




Premium-quality polyvinyl chloride (PVC)

Uniclass 2015

Pr_25_57_51_66 Polymeric membranesPrimary


J42/10 Warm deck roof covering

J42/110 Warm deck roof covering

J42/120 Inverted roof covering

J42/130 Cold deck roof covering

J42/400 Waterproof membrane

Specification data - Polymeric membranes

Product Reference

Sarnafil® S327-EL HD

Top surface colour

Azure blue (nearest RAL 5009)

Copper brown (nearest RAL 8004)

Copper patina (Sika colour 6525)

Lead grey (Sika colour 9500)

Light grey (nearest RAL 7047)

Traffic white (nearest RAL 9016)

Traffic white, solar reflective (RAL 9016 SR)

Window grey (nearest RAL 7040)

Standard product features

Roll size (l x w):

15 x 2 m.


2 mm.


72 kg.


Premium-quality polyvinyl chloride (PVC).



Bottom surface colour:

Dark grey.

Technical properties:

  • Straightness (to BS EN 1848-2): ≤30 mm.
  • Flatness (to BS EN 1848-2): ≤10 mm.
  • Mass per unit area: 2.4 kg/m².
  • Water tightness (to BS EN 1928): Pass.
  • External fire performance (to EN 1187 and BS EN 13501-5): BROOF(t1) <20°, >20°.
  • Reaction to fire (to BS EN ISO 11952-2 and BS EN 13501-1): Class E.
  • Hail resistance (to BS EN 1358): Rigid substrate: ≥25 m/s; flexible substrate: ≥33 m/s.
  • Joint peel resistance (to BS EN 12316-2): ≥300 N/50 mm.
  • Joint shear resistance (to BS EN 12317-2): ≥800 N/50 mm.
  • Water vapour transmission (to BS EN 1931): μ = 15 000.
  • Tensile strength (to BS EN 12311-2): Longitudinal (machine direction): ≥1100 N/50 mm; transversal (cross machine direction): ≥1100 N/50 mm.
  • Elongation (to BS EN 12311-2): Longitudinal (machine direction): ≥12%; transversal (cross machine direction): ≥12%.
  • Resistance to impact (to BS EN 12691): Hard substrate: ≥700 mm; soft substrate: ≥1000 mm.
  • Resistance to static load (to BS EN 12730): Soft substrate: ≥20 kg; rigid substrate: ≥20 kg.
  • Tear strength (to BS EN 12310-2): Longitudinal (machine direction): ≥200 N; transversal (cross machine direction): ≥200 N.
  • Dimensional stability (to BS EN 1107-2): Longitudinal (machine direction): ≤0.3%; transversal (cross machine direction): ≤0.2%.
  • Foldability at low temperature (to BS EN 495-5): ≤-25°C.
  • UV exposure (to BS EN 1297): Pass (>5000 hours/ grade 0).
  • CIGS reflectance (to BS EN 410 in conjunction with CIGS Sensitivity): 95% (RAL 9016 SR, initial).
  • Solar reflectance (to ASTM C 1549): 0.90 (RAL 9016 SR, initial).
  • Initial emittance (to ASTM E 408 and ASTM C1371): 0.85 (RAL 9016 SR, initial).
  • SRI (solar reflectance index, to ASTM E 1980): 112 (RAL 9016 SR, initial).
  • Application temperature: -50°C to 50°C.

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