Roofing underlays

LETO 175

LETO 175 is a BBA-certified, high-performance vapour-permeable roofing underlay designed for demanding pitched roof applications. Manufactured from a durable three-layer polypropylene construction, it combines superior strength, excellent vapour-permeability and W1 water resistance to provide dependable protection against wind-driven rain and external moisture. Suitable for warm and cold roof constructions, LETO 175 is the ideal choice where enhanced durability and technical performance are required without compromising ease of installation.

Solar
Compatible
Vapour
Permeable
W1 Resistance to
Water Penetration
Resists Wind
Uplift
UV Stable
3 Months
UK wind zones map

Wind Zones

Taped laps 1-5
BATTENED LAPs 1-5
BBA CE UKCA

Technical Specifications

Weight, gsm 175
Resistance to water penetration, Class W1
Water vapour transmission (Sd), m 0.02
Tensile strength (MD/CD), N/50mm 350 / 240
Elongation at max. tensile force (MD/CD), % 70 / 70
Nail tear resistance (MD/CD), N/50mm ≥50 / ≥50
Flexibility at low temperature -40°C
UV stability, Months 3
Reaction to fire, Class E
Colour Green

Ideal For

  • Warm roof construction
  • Cold roof construction
  • Vented and unvented roof systems
  • Timber frame and rafter roofs

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Documents & Downloads

BBA Ceritficate - For use in cold non-ventilated pitched roof systems

BBA Ceritficate - For use in warm roof and cold ventilated pitched roof systems