A tin roof has an unpredictable lifespan

It is difficult to make a general statement about the service life that a sheet metal roof can have. As with many other materials, the quality of the material and the type of workmanship are of crucial importance. Higher investments in a tin roof can result in decades of durability. But proof can never be given.

Which sheet is mounted how and in what way

Sheet metal is available in a wide range of quality grades. Theoretically, the best sheet metal can have a lifespan of a hundred years and more. In practice, the average shelf life is estimated at thirty to fifty years, depending on the type of sheet metal and processing.

In addition to the quality of the material and the professional installation, the building physics around the roof structure also have a major influence. A roof structure and the insulation in the substructure ideally prevent problems with condensation. When cleaning the sheet metal, the protection is not damaged, for example by patina or a protective coating.

Properties of common types of sheet metal and metals

The following material categories can be roughly assigned to expected average lifetimes:

  • Galvanized sheet metal and titanium zinc = 30 years
  • Aluminum (anodized) = 30 years
  • Stainless steel (rustproof) = 50 years
  • Copper = 80-100 years

In detail, the metal sheets can develop different lifetimes due to their type of alloy. Highly alloyed indicates a longer service life than low-alloy sheets due to the purity of the material.

With some metals, such as aluminum and titanium zinc, oxidation leads to the formation of a protective layer of their own. When patina develops, this process is known as passivation. As long as the surface remains intact, the patina protects the tin roof just as well as a zinc coating.

Ventilated constructions extend the life of the roof enormously

The service life of a sheet metal roof is decisively influenced by the development of moisture on and in the roof substructure. In the sense of "constant dripping wears away the stone", no sheet metal tolerates permanent moisture well.

Sheet metal roofs, which are installed as so-called cold roofs, achieve the longest service life. The sheet metal does not sit directly on the substructure like layers of insulation. A space in between allows ventilation that allows wet metal sheets to dry well and quickly, even from below. The service life of such roof structures can easily increase by two to five decades.

Tips & Tricks If you have to calculate with a limited budget for your roof, you will get a lower lifespan if you choose a tiled roof instead of a tin roof.