Roof slope

There are numerous types of roofs, which can be divided according to the type of slope into flat roofs, pitched roofs, steep roofs. Various architectural styles prefer various types, with traditional houses having rather steep roofs and sloping or flat modern houses.

What is the slope of the roofs

The slope of the roof is the angle at which the roof is inclined relative to the horizontal plane. It is expressed either in degrees (°) or in percentages (%). Different types of roofing (sheet metal, asphalt, ceramic or concrete roofing) have a recommended different roof slope.

• Flat (even) roof has a slope of up to 5°
• Pitched roof has a slope of up to 45°
• Steep roof has a slope above 45°

However, roofs can also be divided according to shape, into: gable, hipped, pitched, tent or mansard.

What affects the slope of the roof

Depending on the slope of the roof, the following factors may be influenced:

• Water drainage and snow removal

A steeper roof ensures faster drainage of water or removal of snow. It thus reduces the risk of leakage and damage to the roof. Flat or slightly pitched roofs need good waterproofing to prevent water penetration.

• Resistance to wind

Steep roofs (above 45°) may be more susceptible to damage from strong winds. In the case of wind, a roof with a slight slope is more stable. 

• Energy efficiency

Steep roofs usually provide better natural ventilation and heat removal. Flat roofs can overheat more often in summer and, on the contrary, have greater heat losses in winter. However, it also depends on proper insulation. Sustainable green roofs can be a solution.

• Attic use

A steep roof offers better use of attic space because it provides more space. It is thus possible to use the attic for living as well. The flat roof, on the other hand, offers the possibility to use it to create a green roof or terrace.

The slope of the roof therefore affects functionality, safety or look of the building. When choosing, it is advisable to think about aesthetics, weather conditions, type of roofing, maintenance and service life, but also the price.