Roof deterioration

Chiara Del Core 30 mar 2021 Articles 0 comments

Roof deterioration: interventions and remedies

The importance of the roof in relation to a building is undisputed: the roof is in fact an integral part of the structure of the architectural artifact and for this reason it is necessary to ensure its constant conservation and functionality. There are different types of roofs made up of various types of tiles, used according to the local tradition and based on performance characteristics. They range from the most ancient tiles, to the Marseillaise and Portuguese tiles up to the bituminous sheaths typical of continuous roofing. In order to ensure a good level of thermal comfort and correct insulation from external agents, it is necessary to design highly performing canopies.

In this short guide we see what are the structural characteristics of the roofs and what are the interventions to be performed in case of alterations due to the action of time.

Types of roofs

Since its origins, the roof has performed important building safety and protection functions and ensures comfort for users. Over the course of history, different types of roof have succeeded each other which have distinguished themselves for the shape and material that makes up the roofing mantle. This important architectural element is made up of two main elements: the load-bearing structure, which performs the function of supporting the loads that affect the building from above, and the roof which constitutes the outermost layer of the roof and acts as protection against the agents. external. The set of components is completed by the ventilation layer, the insulating layer and the vapor barrier.

The roof is then distinguished in a flat type, with sloping pitches and vaulted; the choice of shape depends on the characteristics of the place where the building is inserted and consequently on the resulting needs. In the northern territories of the world, the frequent rains and snowfalls force the adoption of pitched roofs, thanks to which these loads slide towards the ground line, in order to prevent accumulation and the consequent increase in the load to be supported on the roof. The inclination of the pitches depends on the climatic peculiarities of the specific area, ranging from 10% to even up to 200%. The stratigraphy of this type of roof can be distinguished according to the habitability of the under-stratum area. In fact, depending on whether the area is more or less accessible and habitable, the insulating solution present will also be different. In the case of rooms inhabited in the attic, the recommended system is that of the warm roof which involves the insertion of the insulating layer between the structure and the waterproofing layer of the roof. If, on the other hand, the spaces below the pitch are not habitable, the insulation will concern the floor under the pitch (last floor) and not the roof, which in this case will constitute the cold roof system.

Examples of buildings with pitched roofs


"Carlo Mollino" Alpine Refuge - Gressoney 2010		House Tham & Videgård Arkitekter, Sweden 2012
Photo: AltaVisione		Photo: Ake E: son Lindman

The situation is different in Mediterranean locations, where the sun and low rainfall suggest the use of flat roofs. Sometimes, to increase the thermal performance of the building, in these places the flat roofs become real high-altitude gardens, able to cool and control the humidity level during the hottest seasons. However, even in the case of garden roofs, the maximum slope of 5% must be guaranteed to ensure the minimum runoff of rainwater.

Another type of construction that concerns the roofs is represented by the curved or vaulted roof. These are solutions that do not include the ridge line and where the coverage can be discontinuous or continuous and represented by bituminous sheaths.

First example of a practicable flat roof, introduced in the five principles of architecture by the famous architect Le Corbusier