Spire

As a helmet ( also spire, spire, roof helmet, largely used synonymously ) is called in architecture a pointed roof shape with towers with a polygonal floor plan. This roof shape is common in church towers.

The shape of the pyramid in the basic shape of the helmet is distinguished from the tower marked by a curved, bell-shaped structure of the cupola. Mixed forms are also common.

Spiers have a high aesthetic significance for the silhouette of cities because of their height. The architectural design of the spire can vary greatly.

Constructions

The helmet roof sits on the massive stone tower shaft. In contrast to the tower shaft, the helmet roof usually has a lighter structure. In addition to classic trusses of timber in construction carpenter, there are also structures of iron or steel. The roof is covered with copper plates, slates, shingles or tiles.

Occasionally, the spire was also carried out in stone, partially broken with Gothic tracery. Examples are the tower of the Freiburg Münster or the tower of the Lamberti Church in Muenster.

Helmet roofs have a weight-and material-saving structure. Thus, the towers could be built much higher and cheaper than if they had been carried out massively.

Damage

Spiers are exposed to extreme wind pressures, sometimes it comes to deformations and storm damage. An example is the tower of St. Pancras in Gescher. In danger of collapse due to excessive deformation of an elaborate renovation is necessary.

Lightning strikes due to the exposed position in the past led to frequent fires. Today the helmets with lightning conductors are protected. Nevertheless, it always comes back to a fire, for example by roofing work. Due to the wooden roof trusses and the poor accessibility for extinguishing fires cause severe damage or destruction of the spiers.

Shaping

The size of spiers ranging from small to large roofs and high superstructures. In some cases, the helmet takes a two-thirds or more of total height of the tower. One such example is the tower of the St. Michaelis Church in Hamburg and the tower of St. Peter's Church in Riga.

In the Baroque onion dome was built. This roof form was built mainly in southern Germany and Austria. First, they can be found in the towers of the Frauenkirche in Munich.

Setting up a tower Helmes ( Castle Doberlug, Doberlug -Kirchhain )

Covered copper spiers (left) and hoods (right), Naumburg Cathedral

Large spire ( Hamburg St. Michaelis Church )