ISOLINE LOW LINE For Guaranteed Waterproofing

The Vulnerability of Standard Roofs

Traditional tile and slate roofs are "water shedding" rather than truly waterproof. They rely on gravity and perfect tile alignment to keep water out.

When high winds, heavy downpours, or snow storms hit, tiles can break, shift, or become porous. Underneath them, standard roofing felt degrades, tears, and sags over time. If the felt fails, water enters the building, causing structural rot, mould, and costly interior damage.

Meet ONDULINE ISOLINE LOW LINE

ISOLINE LOW LINE eliminates the vulnerabilities of traditional roof design. It transforms your roof into an impenetrable, dual-layer system where the primary waterproofing is handled below the tiles.

Manufactured from a durable, bituminous composite material, ISOLINE LOW LINE does not rot, tear, or degrade like traditional membranes. It is so reliable that we back it with a 30-year waterproofing guarantee.

ISOLINE LOW LINE

Engineered for Watertight Reliability

30-Year Waterproofing Guarantee: A promise of performance, giving building owners, insurers, and architects absolute confidence.
Corrugation Ventilation: The unique corrugated profile allows continuous airflow beneath the tiles, preventing condensation buildup and protecting structural timbers from rot.
No Sagging, No Puddling: Rigid sheets cannot sag or create water pockets like standard flexible underlays do. Water has no choice but to drain away.
Tested to Extreme Standards: Engineered to withstand torrential wind-driven rain, heavy snow loads, and intense thermal fluctuations without losing structural integrity.

Proven Performance You Can Trust

Onduline’s ISOLINE LOW LINE sub-roof system has been rigorously tested by the Building Research Establishment (BRE), delivering outstanding results under demanding conditions.

Exceptional Waterproof Protection
No leaks were observed during deluge testing, demonstrating reliable protection even under intense rainfall.
Exceeds Industry Benchmarks
Achieved an impressive 111 Pa Pressure Factor—more than three times the BBA target of 30 Pa—highlighting superior resistance to water ingress.
Engineered for Harsh Weather
Proven to withstand wind-driven rain, ensuring dependable performance in exposed and challenging environments.
Outperforms Comparable Systems
Delivered significantly better results than a reference roofing product, confirming its leading-edge performance.
Ideal for Low-Pitch Roofs
Tested successfully at a 10° roof pitch, making it a reliable choice for modern, low-slope designs.
Advanced Overlap Protection
Designed to manage water effectively at critical junctions, maintaining integrity even under increased pressure.
Tested to Recognised Standards
Assessed in accordance with prEN 15601.