Hardly any other roof appears as simple and simple as the monopitch roof. Nevertheless, or perhaps because of it, it has proven to be extremely versatile in its use and at the same time adaptable to the most varied of current requirements. You can find out everything you need to know about this interesting roof shape below.
The creation of the pent roof
When and where the pent roof was built cannot be reconstructed. Due to its simplicity, however, it must be assumed that it has existed for a very long time and that it probably developed independently of one another in numerous places at the same time. If you look at images from the Middle Ages and even antiquity, you will always find buildings that at least suggest that they are covered with a pent roof.
Constructive features and static system
If we look at the construction of a monopitch roof, its structural simplicity quickly becomes the focus of consideration. In general, the framework of the roof - as is the case with numerous other structures - is formed by wooden rafters. These are placed on the outer walls of the building, with a foot and a ridge threshold forming the lower and upper support. From spans of very large five meters between the walls, it is worth supporting the rafters at one or more points between the outer supports. Since all rafters are on one level, the additional support points are usually provided by a beam, i.e. a beam, to reduce the number of supports required further beams at right angles to the rafters below, or in the form of a wall with a threshold resting on it, which is desired there anyway implemented.
NOTE: For each additional support point, the span of the individual fields is reduced and the required rafter cross-section is reduced by reducing the load area per support. In addition, a multi-span beam created in this way is also unequal
more load-bearing than a single-span girder between only two supports. The background to this fact is the fact that the adjacent fields relieve each other when a beam passes through and the deflection is thus reduced.Special shape sandwich roof
Special attention should be paid at this point to the special case that the pent roof is not in Form of a classic rafter construction is built, but created with the use of sandwich elements will. A sandwich element is a combination product of a supporting plane made of sheet metal, a Insulation layer made of foamed plastic materials and a roof covering from one top another sheet. Since load-bearing, insulating and sealing functions are combined in one component, there is no structural support from rafters. Instead, the elements are placed directly on the required number of supports in the form of walls or beams.
The roof structure with sealing and insulation
The most common case with the monopitch roof, however, is still the classic rafter construction. Therefore, a typical structure of a monopitch roof using a rafter system will now be explained as an example. From the bottom (inside) to the top (outside), the following layer structures result for a roof with thermal insulation inserted between the rafters:
- Lower clothing, e.g. B. Wood or plasterboard, on battens
- Vapor barrier as a diffusion-proof layer
- Rafter layer with inserted thermal insulation, e.g. B. Mineral wool or cellulose insulation
- OPTIONAL: Additional insulation layer on the rafter layer, usually also effective as a watertight layer
- Watertight layer, usually in the form of a film (if not provided by another layer of insulation)
- Roofing - for the different types of roofing, see the following section
Alternative structure with insulation layer on rafter layer (from bottom to
above):- Rafter position
- Formwork made of plasterboard, wood, etc.
- Diffusion-tight layer, e.g. B. as a foil
- Insulation layer, either pressure-resistant as plastic foam, or soft as mineral wool or cellulose; In the case of soft insulation, wooden supports are required for the roof covering
- Waterproof level, usually as a foil
- Roof covering - see the following section
Roof coverings and slopes
While the actual roof structure is quite uniform, the actual roof covering and its substructure can differ greatly from roof to roof. Numerous variants are available for the monopitch roof:
Bricks and concrete roof tiles
Bricks and concrete roof tiles are identical in terms of their use and function, but differ in the material used, clay or concrete. As a rule, they are applied to a two-layer substructure made up of counter battens running from bottom to top and the actual support battens perpendicular to the direction in which the roof rises. The tiles or roof tiles are simply hung into the battens with a nose on the back and, if necessary, partially fixed over the roof surface against strong wind suction using additional securing.
INFO: The counter battens must always run along the slope of the roof so that any rainwater blown under the tiles can run off. On the other hand, transverse battens on the waterproof layer would act as a brake for the water.
- Minimum suitable inclination: usually 15 degrees, some types of bricks also up to 10 degrees
- Maximum suitable inclination: depending on the type of tile and securing, 45 degrees and more can be implemented without any problems, but then usually no pent roof makes sense
Foil or bituminous waterproofing
A homogeneous, flat roof covering is the execution over roofing membranes based on foil, or as a bituminous roofing membrane. Both differ in the type of materials, the bonding and the optics. Otherwise, however, they can be regarded as identical.
1. With rear ventilation:
As a roof covering with rear ventilation, battens are attached to the watertight layer, which allow air to circulate to remove any moisture. This is followed by a load-bearing board made of wood, onto which the foil or bitumen roof is then applied.
2. Without ventilation:
Bitumen sheets or foil are applied directly to the insulation layer. There is no watertight layer underneath.
- Tilt: Both materials can be used from zero degrees
Greened / graveled
Neither a gravel roof nor a green roof are separate types of surface. Both coverings are based on a foil or bitumen roof. Frequently
NOTE: A green roof can also help cool a house in summer thanks to its water storage capacity and the ability to evaporate this rainwater again.
sheet
Finally, sheet metal is often used as a roof covering, especially on flat monopitch roofs. The sheet metal roof requires the same substructure as the foil roof, but is usually only designed in a rear-ventilated form.
- Minimum suitable inclination: 5 degrees
- Suitable inclination maximum: unlimited
Roof structures and installations
Classic roof structures such as dormer windows or roof cut balconies do not exist with the monopitch roof. Skylights can sometimes be used with pitched monopitch roofs, but skylights are more common with the mostly flat pitch. In many cases, however, such additional lighting and ventilation is completely dispensed with, since the pent roof makes it easier to accommodate normal facade windows in the vertical walls.
costs
Although the real costs can of course only be determined with a specific object reference, it can also be said without considering individual cases that a monopitch roof is a very favorable roof shape. Since the roof consists of only one surface, expensive construction details are reduced to a minimum and special points such as ridge, ridges, valleys, etc. completely avoided. It is true that more external wall surfaces are required for an equivalent roof space under your monopitch roof than with one Gable roof for example would be the case. However, this is offset by better usability due to vertical walls and fewer roof slopes. It tends to be easy to say that the monopitch roof is all other Roof shapes from an economic point of view clearly outstrips the rank.
Advantages and disadvantages
Numerous advantageous aspects of the monopitch roof are of course offset by some disadvantages:
advantages
- Good usability of the rooms below due to the few sloping ceilings and the lack of gables
- Simple construction
- Thus: low susceptibility to damage due to a few, simple details
- Thus: low costs due to the lack of complex components
- Versatile in inclination
- Diverse optical design options
- Large roof area without changes in inclination or position, well suited for solar thermal or photovoltaics
disadvantage
- With a steep incline, unusable space in the upper attic area
- Simple optics, playful design therefore usually difficult
- Very high wall height on the ridge side
