Types Of Roofing Forms

A distinction is usually made between two types: the inclined roof, and the flat roof, differing from each other by their inclination with respect to the plane of the ground, slightly inclined in the second case.


Both types of roofs have a great tradition in architecture; the inclined ones were used more in mainly rainy climates because they allow water to be evacuated by simple gravity, and the flat ones in drier climates, where the problem of rain is episodic and the problem of almost unknown snow; the terrace roofs have advantage or habitability in the nights of the warmest seasons, even to sleep outdoors.2


As waterproofing systems have improved, the flat roof has extended to rainy climates as well. This is why the flat roof has become characteristic of a type of architecture that began at the beginning of the 20th century in the rainy countries of northern Europe, called the Modern Movement, countries with a long tradition of inclined roofs, where the flat roofs were shocking. The advantage attributed to this movement, in those very cold countries, is to leave the accumulated snow on the roof forming a “coating” insulating from the cold. In the past, this was not done because their weight caused serious problems, such as frequent sinking on roofs with a slight slope, and they were done with a great slope, so that the snow would slide towards the ground. The Modern Movement takes advantage of the best knowledge on calculation of structures and more modern systems of construction.


Roof in pavilion, hipped


Each plane that forms an inclined roof is called a skirt. The edges separating each skirt are called limes, which can be limahoya (in the concave part), limatesa (in the convex part) or lime of break (between cloths with different inclination). The upper crowning file is called ridge, easel or gallur. The lower ends protruding from the façade (to keep the water from falling out of the building) are called the eaves or alar.


The elements that can appear on a roof to illuminate and ventilate the interior are usually called skylights. On traditional sloping roofs, they can be called the beata, also called the attic; the gablete, the lucero, lucernario, lumbrera or skylight; and the montera.


For a better protection of the facades, the inclined roofs extend beyond the plane of the facade forming a eave or wing.


To describe the shape of the inclined roofs, reference is usually made to the number of skirts, which -especially in this case- are called “waters”, thus we speak of roofs with one water, two, three, four or more waters. In gable roofs, the enclosures of the building towards which the water does not pour end in a triangular shape known as a gable or pinion.


The biggest problem with flat roofs is that they are subject to large temperature differences and should therefore be divided into “quarters”, i.e. sections that are not too large in size (it is generally accepted that they have a maximum dimension of 6 m in either direction), leaving an expansion joint between them. Each barracks forms a kind of funnel with horizontal perimeter edges and from them, skirts are formed with little slope towards the point of drainage. In small buildings, they are made upside down, similar to inclined roofs, draining out of the perimeter of the building, but with less slope. There are techniques to avoid having to make these divisions as small as the inverted roof.


In certain types of flat roofs, such as the so-called Catalan roof, the roof is also extended outside the façade plane forming an eaves, generally less protruding than on sloping roofs.