The roof, as the fifth facade of the building, mainly carries the functions of waterproof, heat insulation and daylighting. In recent years, with the differentiated demand for architectural features, the roof is also considered to be an important part of architectural modeling, which needs to be considered in the design. When many customers come to us for design, they always find it difficult to choose flat roof or sloping roof. This article will introduce you and roughly explain the similarities and differences between the two, so that you can have a basic understanding when choosing.

First, let’s talk about the commonness of flat roof and sloping roof.
Both of them are required to have the characteristics of waterproof and thermal insulation in function, and both need waterproof layer and thermal insulation layer. There is no saying that the waterproof performance of slope roof is better than that of flat roof. Sloping roof is used in rainy areas because it has its own slope, which is easy to drain the rainwater from the roof. However, in terms of waterproof structure, flat roof and sloping roof need two waterproof layers. Flat roof can be a combination of asphalt coiled material and waterproof coating. The tile of sloping roof itself is a waterproof protection, and a waterproof layer is paved below.
The waterproof performance of roof is mainly determined by waterproof materials and structures, which has little to do with the selection of flat roof and sloping roof. You can think of the flat roof as a large pool, but the purpose of this pool is not to store water, but to let the water drain quickly through the downpipe. Because the slope is small, the drainage capacity of flat roof is not as fast as that of sloping roof. Therefore, flat roof is generally used in areas with little rain in the north.

Secondly, let’s talk about the differences between the two
In terms of classification, flat roof and slope roof can be used in several different forms, including ventilation roof, water storage roof, planting roof, etc. These roofs are determined according to the region and climate of the house. For example, ventilation roof and water storage roof will be selected in hot areas. The former is conducive to indoor ventilation and flow exchange, and the latter can play the role of physical cooling. Because of different slopes, planting and water storage roofs are generally used on flat roofs, and ventilation roofs are more used on sloping roofs.
In terms of structural level, there are relatively more levels of pitched roof.
The structural level of flat roof from the roof structural plate to the top is: structural plate – thermal insulation layer – leveling layer – waterproof layer – isolation layer – protective layer
The structural level of sloping roof is from the roof structural plate to the top: structural plate – thermal insulation layer – leveling layer – waterproof layer – nail holding layer – downstream strip – tile hanging strip – roof tile.

In terms of materials, the material selection of sloping roof is more than that of flat roof. Mainly because there are many kinds of tile materials now. There are traditional small green tiles, glazed tiles, flat tiles (Italian tiles, Japanese tiles), asphalt tiles and so on. Therefore, there is a lot of space in the design of color and shape of pitched roof. The flat roof is generally divided into accessible roof and non accessible roof. The accessible roof is generally paved with block surface course to protect the waterproof layer below. The inaccessible roof is directly paved with cement mortar.

In terms of function, the practicability of flat roof is greater than that of slope roof. It can be used as a terrace for drying. It can be used as a roof garden combined with the landscape. It can also be used as a viewing platform to see the distant mountains and the starry sky. Moreover, the view of the roof is invincible with the sun, which is a rare outdoor space.

In terms of facade design modeling, as the “Fifth Facade”, the modeling freedom of sloping roof is significantly more than that of flat roof. There are many design methods, such as continuity of different sloping roofs, interspersed combination, staggered peak opening, etc.