Roof coating or coated roof tiles

Roof coatings are almost always offered as a renovation for intact older roofs. At the same time, however, there are also glazed and engobed roof tiles in the trade - in other words practically coated from the factory. What difference that makes, and where the technical advantages lie, read here.

Warning of roof coatings

Subsequent roof coatings are supposed to seal intact roofs and ensure a longer durability.

However, many experts warn against such work, for several reasons:

  • The previously required roof cleaning can cause damage to the roof
  • Joints between the roof tiles can be closed by the coating
  • the material properties of the roof tiles are changed
  • The rain protection function of the roof is changed
  • Inferior, non-frost resistant coatings can flake off
  • improper order can lead to irreparable damage to the roof
  • in a subsequent coating, the overlapping of the roof tiles are not coated - the coating is therefore only partially - which is technically unfavorable

The counter arguments against a roof coating are therefore manifold. In not a few cases, the roof tiles are so badly damaged by an improper coating, that after only a short time an expensive expensive new roofing threatens.

Coated roof tiles

Roof tiles can either be engobed or glazed. In this way, they are practically factory-provided with a comprehensive, protective coating.

Unlike in the case of subsequent coating, this protection envelops the roof tile at all points, even where the roof tiles overlap after installation.

The joints also remain intact, since the coating is already applied directly on the roof tile from the outset, and not only subsequently applied to the entire roof.

Performance of engobes and glazed roof tiles in comparison

Traditional clay roof tiles

Even ordinary clay roof tiles have a durability of many decades. Usually manufacturers give up to 30 years warranty on clay roof tiles. Even after this time, however, often only punctual damage occurs, which can be remedied by replacing individual roof tiles.

In practice, high-quality roof tiles can be expected to last 50 to 60 years, and often even longer.

engobes

Engobes are provided with a clay slurry during manufacture. The application can be done in different ways. Engobes remain highly permeable and breathable. The clay slurry can be mixed with different minerals or metal oxides.

The surface coating is essentially only the color of the clay brick, but also has certain protective properties, through the glass-like surface. So-called Edelengoben are classic engobes whose clay slimes are added to glass bodies. This retains breathability, but a protective, very hard layer covers the tile.

Unlike the glaze, there are no cracks on the surface (so-called Krakeelen).

Glazed roof tiles

Glazed roof tiles have a high degree of gloss. The surface is covered by a very hard, glassy layer. It is tight, preventing water from penetrating the roof tile. This avoids some possible damage.

Over time, however, tensions in glazed bricks may cause slight surface cracks (craquels or cracks). This weakens the protective function of the surface.

In practice, the durability of engobes and glazed bricks is not significantly superior to that of conventional clay roof tiles, but a somewhat higher protective function for the brick is certainly given. But even with the roof coating there is no conclusive indication of an actually longer life of the roof, it is a purely cosmetic measure.

Video Board: Repairing a Shingled Roof (Roll on Coatings)