Slope roof load-bearing structure Slope roof material Slope roof structure requirements

The form and slope of sloping roof mainly depend on building plane, structural form, roofing material, climate environment, customs and architectural modeling and other factors.

Roof with drainage gradient greater than 10% is called sloping roof or sloping roof.

The form and slope of sloping roof mainly depend on building plane, structural form, roofing material, climate environment, customs and architectural modeling and other factors.

form

Sloped roofs are widely used in buildings, mainly including single slope type, double slope type, four slope type and folding type. Double slope and four slope are widely used. The gable protruding from the top of the double-slope roof is called hanging mountain; A gable with a flat roof is called a hard mountain. The four corners of the traditional four slopes in China are inclined, which is called the Temple of Heaven. The main ridge extends and two mountain flower faces are formed on both sides, which is called inclined mountain. The tile line intersects with the sloping roof in the form of pyramid roof, and the treasure roof is often arranged at this point.

Slope roof The slopes of a double-slope or multi-slope roof intersect, and the horizontal intersection line at the top is called the positive ridge; The oblique line that the inclined planes intersect to form convex angles is called oblique ridge; The diagonal line that the inclined planes intersect to form a concave angle is called an inclined gutter. A sloping roof without a positive ridge is called a rolling shed roof. Hard hilltops, suspended hilltops and resting hilltops can all be made into roll sheds.

In addition, the sloping mountain, Ding Dian and pyramid roof can also be arranged in the form of double eaves as required.

slanting

The slope of the roof is expressed by the ratio of the projected height (rising height H) of the inclined plane on the vertical plane to the projected length (half span L/2) on the horizontal plane. It can also be expressed by height-span ratio (the ratio of rising height h to span l); Or the included angle between the inclined plane and the horizontal plane. Whether the selection of roof slope is reasonable or not affects the waterproof effect of roof. The slope is mainly determined by the performance and structure of the selected roofing waterproof layer material. If you choose materials with good waterproof performance, large single block area and few joints, such as coiled materials, self-waterproof components, metal sheets, etc. The slope can be smaller; If the roof is paved with tiles, the tiles are small, there are many joints and the slope is larger. In cold areas, in order to prevent a lot of snow on the roof, the slope should be steep; Roof with attic often adopts steep slope roof or two kinds of folding roofs with different slopes (Xia Meng roof).

load-carrying members

Yamagata bearing

For a building with a small room, a peak-shaped purlin is laid on the load-bearing wall, which is called? Gables bear weight? Or? Hard mountain rack? . Purlins are equidistantly arranged, including wooden purlins, steel purlins and precast reinforced concrete purlins. The cross-sectional dimensions of purlins should be calculated and determined according to the material, span, spacing and load, and the span of purlins should generally not exceed 4m. Purlins can be directly paved with 15 ~ 25mm thick plates. This is called? See the blackboard? ; You can also put the rafters on the purlin first, and then lay the lookout.

Roof truss support

For buildings with large rooms that cannot be supported by gables, roof trusses must be set to support purlins. Roof truss is composed of bars, which is a plane structure. It can be made of wood, reinforced concrete, prestressed concrete or steel, or a combination of two or more materials. Roof trusses are triangular, arched and polygonal. Most of them are triangles. Roof truss spacing is generally the same as the width of the house, generally 3 ~ 4.5 meters.

Raft bearing

Brackets made of closely arranged herringbone rafters are supported on longitudinal load-bearing walls, which are covered with wooden boards or directly nailed with tiles. The general spacing of the rafters is 40 ~ 120cm, and there must be horizontal tie rods between the herringbone rafters of the rafters.

Roof bearing

Large roof panels made of reinforced concrete or other materials are directly placed on load-bearing gables or roof trusses.

Roofing material

There are many kinds of roofing materials, and the selection should be based on supporting structure, roof slope, architectural appearance, durability, fire resistance, waterproof, self-weight, construction requirements, cost and other factors. Commonly used are:

Flat tile roof

This kind of roof is made of clay or cement mortar and molded into uneven flat tiles. The overall dimensions of ceramic tiles are generally 400? 230? 15mm, with hooks on the back of the tiles, which can be hung on the battens. When laying, it must overlap up, down, left and right. This kind of roof is easy to build and widely used in civil buildings. Its disadvantages are small tile size, many joints and easy water leakage.

Wavy tile roof

This kind of roof is commonly used with asbestos cement corrugated tile, steel wire mesh cement corrugated tile, colored glass fiber reinforced plastic corrugated tile, galvanized corrugated iron tile, aluminum alloy corrugated tile and wood fiber corrugated tile after surface coloring and anti-corrosion treatment. Corrugated tiles are light in weight, good in appearance and waterproof, and all kinds of corrugated tiles are covered in similar ways. For example, asbestos-cement corrugated tiles are usually directly nailed or hooked on purlins with galvanized iron screws or iron hooks, and the spacing between purlins is generally 900 ~ 1200mm. Tiles should be covered from top to bottom and from left to right, and the direction of covering from left to right should follow the dominant wind direction. In order to prevent the joints of the upper, lower, left and right tiles from being uneven, the corner-cutting paving method is generally adopted.

Other roofs

In addition, there are glazed tiles, small blue tiles, cylindrical slab tiles and precast reinforced concrete tile roofs. At present, glazed tiles are mostly used in large public buildings, such as memorial halls, as roofs or eaves decoration; Small blue tiles and cylindrical tiles are mostly used in residential buildings; Reinforced concrete roofs include п-shaped plates, F-shaped plates and steel wire cement trough tiles. They are large in size and can be directly laid on roof trusses or purlins, and there is no need to make another roof (see component self-waterproof roof).

Structural requirements

thermal insulation

Thermal insulation should be considered for sloping roofs of heating buildings in cold regions. There are usually two methods of roof insulation and ceiling insulation. Roof insulation means placing insulation materials under the waterproof layer of the roof, such as laying ceramic tiles directly with wheat straw mud or laying lightweight insulation board under the roof in the traditional structure. There are two methods for ceiling insulation: one is to lay lightweight insulation materials on the ceiling; The other is to use the thermal insulation performance of the ceiling material itself. In the design of these two methods, attention should be paid to ventilation, moisture insulation, corrosion prevention and fire prevention of thermal insulation structure.

Thermal insulation ventilation

The purpose is to reduce the influence of indoor radiant heat and protect roofing materials. In a sloping roof with a roof, the vent of the mezzanine space between the roof and the ceiling can be located at the cornice, roof ridge or gable, and the ventilation tiger window can also be located on the roof.

upturned eaves

The cornice is the joint between the roof and the wall, which plays a role in protecting the wall and is also the decorative part of the building facade.

vent

According to the length of overhangs, there are many ways to fly eaves: brick overhangs can be used if there are few overhangs; If there are more overhangs, you can use rafters to overhang the eaves, expose the eaves or nail them to the eaves; If there are many overhangs, the joists of the lower chord of the roof truss or the overhanging wood pressed into the wall can be picked out, and purlins are set to increase the depth of the eaves.

drainage

The rainwater on the sloping roof can be freely discharged downward along the roof through the eaves; You can also set a horizontal gutter with a slight longitudinal slope at the cornice, so that rainwater can be collected and discharged through vertical rainwater pipes with certain spacing.