Product Data Sheet Show all documents

Cromar® High Perf Underlay 180 Polyester Sanded

A high performance, polyester reinforced bitumen roofing underlay.

Designed for use in built-up flat roofing systems.
Manufactured using a 180 g/m² spunbond polyester carrier, the membrane is fully coated with oxidised bitumen and finished with a fine sand surface on both sides, providing excellent adhesion when installed using traditional pour-and-roll hot bitumen techniques.

  • High-performance polyester reinforcement for improved strength and stability.
  • Sanded surface finish to ensure positive bonding between layers.
  • Excellent resistance to water ingress when correctly installed.
  • Flexible and easy to cut and form on site.
  • Compatible with traditional hot bitumen pour-and-roll installation methods.
  • Proven durability when used within a correctly specified built-up roofing system.
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Product Data Sheet Show all documents

Usage

  • Secondary underlay layer in built-up roofing systems.
  • Intermediate layer beneath mineral or cap sheets.
  • Suitable for commercial and domestic flat roofing applications.
 

Advantages

  • High-performance polyester reinforcement for improved strength and stability.
  • Sanded surface finish to ensure positive bonding between layers.
  • Excellent resistance to water ingress when correctly installed.
  • Flexible and easy to cut and form on site.
  • Compatible with traditional hot bitumen pour-and-roll installation methods.
  • Proven durability when used within a correctly specified built-up roofing system.

Packaging

 Sleeved

Product Details

Product Information

Shelf Life

18 months

Storage Conditions

  • Store rolls upright on a dry, level surface
  • Do not drag rolls across rough surfaces
  • Avoid damp conditions and prolonged exposure to direct sunlight
  • Do not install at temperatures below + 5 °C

Dimensions

1 m x 20 m

Mass per unit area

1.8 kg m2

Felt weight

36 kg
Technical Information

Tensile Strength

890 N/50 mm MD
590 N/50 mm CD

Elongation

38 % MD
46 % CD

Tear Strength

150 N MD
140 N CD

Reaction to Fire

EN 13501-1
Class F

Application

Application steps

APPLICATION INSTRUCTIONS

  • Installed using traditional hot bitumen pour-and-roll bonding techniques.
  • Typically protected by subsequent roofing layers and not intended for prolonged exposure.
  • All roofing work should follow current British Standard code of conduct.

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