Clinker brick

[3] Clinkers are water-resistant and durable, but have higher thermal conductivity than more porous red bricks, lending less insulation to climate-controlled structures.

[5] Initially, these clinkers were discarded as defective, but around 1900, the bricks were salvaged by architects who found them to be usable, distinctive, and charming.

Both terms are onomatopoeic, derived from the Middle Dutch klinkaerd, later klinker, from klinken (“to ring, resound”).

Some used clinkers to spell out their family initials on brick dwellings such as the Jan Van Hoesen House.

For the production of masonry units the source materials—clay and water—are mixed and formed industrially in a string extrusion process.

The German sculptor Ernst Barlach worked with clinkers, which were produced according to his specifications, for example by the brickyard of Ilse Bergbau AG.

[citation needed] Clinker bricks take on a special coloring, often greenish tones, if burnt with peat.

The Chilehaus and the Ramada Hotel in Hamburg are famous buildings built with peat-fired clinker.

The surface of a Klinker brick is so hard that it is almost glass like and any rough edges wouldn’t soften.

Reemtsma cigarette factory in Hamburg by Fritz Höger
A piece of vitrified brick
Clinker bricks used to form family initials on the Jan Van Hoesen House , a 1700s Dutch house in upstate New York .
Clinker brick closeup of bricks in the so-called Clinker building on Barrow street in Greenwich Village, New York City.
Dutch bricks ( clinkers ) found at Topsham Museum. Imported between 1660 and 1710, they were used for finer details such as fireplaces. They can be seen in many buildings in Topsham and are sometimes used in boundary walls.
Historical floor at the Jagdmagazin, Jagdschloss Grunewald , Germany
Lubelska brick floor tile shows variation in color due to heating