ISOLINE LOW LINE For Low Pitched Roofs
Achieve Traditional Clay and Slate Roof Designs on Pitches as Low as 10°
Challenge the Pitch. Don't Compromise on Tiles.
The Low Pitch Dilemma
Modern architecture, home extensions, and certain planning restrictions often demand a low roof pitch. However, traditional clay tiles and natural slates typically require steep pitches to shed water effectively.
If you try to install traditional tiles on a low pitch, you risk severe water ingress, wind-driven rain penetration, and premature roof failure. Architects are often forced to abandon beautiful tile aesthetics for flat roofs or steep pitches - until now.
Meet ISOLINE LOW LINE
ISOLINE LOW LINE completely redefines what is possible with low-pitch roofing. Acting as a sub-roof waterproofing system, it becomes the primary water-shedding barrier beneath your tiles.
Because the sub-roof is fully corrugated and engineered to handle high water volumes at shallow slants, you can safely install traditional clay, concrete, or slate tiles far below their manufacturer-recommended minimum pitch.
Break the Architectural Rules: Bring the timeless beauty of traditional tiling to modern, low-pitch extensions and designs down to 10°.
Why Low Pitch Designs Need ISOLINE LOW LINE
- Unlock Lower Pitches: Safely install clay or concrete interlocking tiles and natural slate down to 10°.
- Anti-Ponding Engineering: The corrugations create clear drainage channels, ensuring water flows freely to the gutter without pooling, even at shallow angles.
- Ultimate Wind-Driven Rain Protection: Standard roofing felts sag and trap water at low pitches; ISOLINE LOW LINE maintains its rigid profile to actively channel wind-driven rain away.
- Expanded Living Spaces: Perfect for single-story rear extensions where existing first-floor windows restrict the available roof pitch height.
How it works: A Fully Waterproof Sub-Roof System
Rather than relying solely on the outer tiles to keep water out, ISOLINE LOW LINE acts as the primary weatherproofing layer. Installed directly over the roof structure, the rigid corrugated sheets form a continuous drainage plane that safely channels water down to the gutter - even on shallow roof pitches.
The external clay tiles, concrete tiles, or natural slates then function primarily as the architectural finish, delivering the traditional appearance homeowners and planners demand.
Why ISOLINE LOW LINE Is Different
Most low-pitch solutions force architects and homeowners to compromise on appearance by switching to flat roofing membranes or modern metal finishes.
ISOLINE LOW LINE uniquely bridges the gap between traditional roofing aesthetics and modern low-pitch performance by introducing a fully corrugated waterproof sub-roof beneath the visible tiles.
This means the roof can:
- Retain the authentic appearance of clay tile or natural slate
- Operate safely at reduced pitches
- Resist wind-driven rain more effectively than standard felt systems
- Avoid the sagging and water trapping associated with conventional underlays
- Enable lower ridge heights for restricted extension projects
Professional Development & Support
Master High-Performance Roofing: Book Our CPD
Discover how to spec roofs that withstand modern climate challenges and protect high-value properties. Join our CPD session:
"Understanding Low Pitched Roofs And The Benefits Of Sub-roof Systems"
Expert Guidance
Designing a challenging low-pitch extension or dealing with strict height restrictions? Contact Onduline today for precise calculations, technical detailing, or project assistance.