Onduline under roofing solutions are installed under the existing roof: they are not visible from the outside of the building, but they are designed to ease the installation on-site for roofers and improve the well-being inside the building for the inhabitants.
Onduline offers 2 main under-roofing systems: 

  • ISOLINE, a roof under the roof when the building is made of clay tiles, to ensure a long-lasting waterproofing
  • ONDUTISS range of breathable underlayers, vapour barriers and other foils that protect insulation, roof, and walls, to keep a dry roof and avoid the development of moistures. 


Easy and fast to install ISOLINE under roofing solutions for clay tiles roofs


ISOLINE is one of our under-roofing product line that we like to call "a roof under the roof". With time, tiles can move, break, freeze, become porous... Our ISOLINE system creates another layer under the original clay tile roofs. This system ensures a long-lasting waterproofing. With ISOLINE, we add a small weight (3 to 4 kg by m²) and we keep the existing tiles (when they are in good shape). The original aesthetic of the building is preserved, while the building waterproofness has been improved.

With this under roofing solution, people living inside the building benefits from a better thermic and acoustic comfort – as the rain noise is reduced. Ventilation is optimal with our under roofing solutions, meaning that between our Isoline tile and the roof, the tile doesn't stay humid and therefore, last longer. It also allows to have roof with a lower slope degree, which mean more space available in the attic.


Another benefit, the building is made waterproof really fast, which can be useful in some cases.Thanks to their size, ISOLINE under-roofing sheets protect about 2 m² of roof as soon as they are installed. They bring an immediate weatherproofing. 
The time needed for workers on the site is also reduced as it is easy and fast to install. The ISOLINE under-roofing sheets have a specific shape that is thought to be quick and simple to install. They have a specific form to ease the lay down of tiles and their alignment.


ISOLINE Under-roofing systems can be applied progressively by vertical columns, allowing a step-by-step progression of the renovation. There is no need to stock or move up and down the existing tiles, they can just be put aside during the time of the installation. Their rough surface is designed to maximise anti-slip performance. 


Ondutiss under roofing solutions: enhanced protection for your roof


ONDUTISS is a large range of high-quality membranes and foils that are invisible when installed but are essential to protect the building. 

Depending on the needs, Onduline offers solutions like: 

  • Breathable membranes called ONDUTISS AIR, to protect the insulation and ensure a proper ventilation of the roof. They also avoid rain, snow and dust to come in the building. Their main characteristic is the vapour-permeability: the water vapour can go outside the house and it limits the development of moisture inside the building 
  • Vapor barrier, like ONDUTISS BARRIER and ONDUTISS BARRIER REFLEX are vapour proof foils that protect the insulation from inside the building
  • Bituminous membranes like ONDUTISS STRONG to protect roofs and attics… 

ONDUTISS comes in rolls, which are easy to carry and to install. The film is protected by the bottom level and the upper level that ensures waterproofness and prevent damages from the UVs.

Have an overview of our main products. Any question, please contact your local team, they will be glad to help you.



High-performing underlayer systems for clay tiles roofs

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