Non-combustible vs. non-flammable materials

There is an essential difference between a non-combustible material and a material that is merely non-flammable. The first never burns, regardless of the heat source. The second resists fire under certain conditions, without being entirely invincible against flames.

The 1915 fire in Reykjavik

This nuance had considerable importance one evening in 1915, when Reykjavik saw a large part of its center go up in smoke. While traditional wooden houses collapsed one after another, other buildings, covered with a material now associated with Iceland's visual identity, held firm.

Corrugated iron's role in Iceland

Since then, corrugated iron has never left the urban landscape of Iceland. It tells a story much richer than a simple aesthetic choice. The scarcity of trees in Iceland pushed the inhabitants to import corrugated iron from the United Kingdom as early as the end of the 19th century to protect their wooden homes.

Iceland's lack of trees

To understand why Icelanders became enamored with corrugated iron, one must go back to a very concrete problem: the almost total absence of trees on the island. The massive deforestation that occurred as early as the arrival of the first Viking settlers deprived the country of a resource that other European nations exploited without restraint.

Architectural adaptation

Building with solid wood became a luxury, since wood had to be imported, mainly from Denmark or Norway. For centuries, Icelanders therefore lived in turf houses, the famous torfbæir, which offered adequate natural insulation but required constant maintenance. The arrival of corrugated iron, imported from the United Kingdom at the end of the nineteenth century, changed the situation.

Fire resistance of corrugated iron

This material, light, inexpensive and easy to transport, allowed the covering of wooden structures without the need for large amounts of local raw material. The inhabitants quickly adopted this solution to protect their facades from the weather, thus creating a recognizable architectural style, with its bright colors that still brighten the streets of Reykjavik today.

The 1915 fire's impact

The fire that ravaged the center of Reykjavik remains a significant episode in Icelandic urban history. The flames spread rapidly from one house to another, taking advantage of the dry wood and the proximity of the buildings. However, some buildings resisted better than others, and this was not by chance.

Material properties and fire

The houses whose wooden frames were fully covered with corrugated iron benefited from a physical barrier that slowed the spread of fire outward and limited the oxygen supply to the most vulnerable parts of the structure. Metal does not burn in the same way as wood. It deforms under the effect of intense heat, but it does not feed the flames as would a wooden cladding.

Thermal insulation challenges

Corrugated iron has many advantages, but it also has a major drawback in a country where winter temperatures regularly hover around negative values and where the wind blows with formidable intensity: metal is a very poor thermal insulator. Unlike stone or solid wood, it allows the interior heat to escape at an impressive speed as soon as it is not accompanied by a high-performance insulation underneath.

Multi-layer construction systems

Icelanders therefore had to deal with this constraint by developing multi-layer construction systems. Corrugated iron plays a role of external protection against rain, snow and wind, while the actual insulation is located inside, between the wooden frame and the interior cladding.

Condensation risks

The importance of insulation and the risk of condensation in case of poor design constitute the real Achilles' heel of this type of housing. When the warm and humid air from the inside meets the cold surface of the corrugated iron, condensation can form inside the wall, in a space where it should never appear.

Preventing condensation

This trapped humidity promotes the rot of the structural wood and the degradation of insulating materials, reducing their effectiveness year after year. To avoid this phenomenon, Icelandic builders have learned to integrate several essential elements, which are now found in the renovation standards of old buildings.

Modern renovations

These principles, now well documented, were not always mastered in the oldest constructions, which explains why some historical Icelandic houses have experienced humidity problems over the decades. Recent renovations focus precisely on correcting these flaws while preserving the characteristic exterior appearance of these houses.

Legacy of corrugated iron

More than a century after the great fire in Reykjavik, corrugated iron continues to cover thousands of Icelandic facades, between historical necessity, protection against the elements and the permanent challenge of good insulation. A modest material, but one that tells much of the country's history on its own.