1. Add an underlay screen.
The HPV (Highly Permeable to Water Steam) underlayment screen helps to waterproof your roof with air and water while allowing water vapor to escape. It reduces pressure-depression phenomena of the roof, responsible for the flight of tiles during storms, which allows the installation of tiles on lower slopes. It finally avoids the penetration of powdery snow, dust, pollen. How to choose the screen? Everything depends on the frame, the spacing of the rafters, the type of coverage, but also the presence or not of attics.
Only a professional can judge the feasibility of the operation. Opt for a quality product and thick enough because it is made to last. Once installed, the screen is exposed to the risk of aging, firstly because of UV rays (before the laying of the cover), then hot weather under the cover in summer (they can exceed 80 ° C). Some membranes have a metallized surface and therefore reject some of the heat in summer, while reducing winter energy losses and allowing water vapor to escape.
2. Install roof windows.
Quality roof windows (with good thermal and sound performance) provide appreciable solar energy in converted attics. Peripheral connections must be perfectly executed to ensure reliable sealing and thermal insulation. Today there are models suitable for classified buildings, metal or wood.
3. Opt for a green roof.
It can be installed flat roof or sloping, regardless of its size. It offers good thermal and sound insulation. The professional must check if all the requirements for the installation are met. In the north of France, the green roof will generally be lighter than in the South. The abundant rains will feed the plants, so the watering system is less complex. It will be necessary to provide a high-performance waterproofing membrane (a conventional under-roof screen is not suitable because it is permeable to water vapor). The attic, them, must have an effective and adjustable ventilation to avoid condensation. Last tip: choose a system whose plants are mostly mature when laying.
4. Install photovoltaic tiles.
More aesthetic but more expensive than large panels, the “tiles” photovoltaic (in fact, small stackable panels) adapt well to slate or terracotta roofs. The watertightness of the roof must be guaranteed and provide good ventilation of the roof, because the panels generate a real overheating, too often neglected. This overheating is also detrimental to the performance of the photovoltaic panel. For a zinc cover, the integrated panels are specific because the contact between different metals causes an accelerated oxidation. It is better to go to a QualiPV zinc fitter and opt for products that have received a technical opinion (issued by CSTB).