Almost everyone who was engaged in the construction of a country house and the construction of its roof had a question: what is and how to make roof gables with your own hands? This article is intended to answer this question, as well as to talk about how their construction is carried out correctly and what requirements are imposed on the gables.
Pediment sheathing
The roof pediment is an element of the front facade of the building, the boundaries of which are a cornice and two roof slopes.Illiterate arrangement of the pediment can lead to such consequences as cracks leading to the collapse of the gable walls.
Most often, the destruction of gable walls occurs as a result of miscalculations in the design of the house.
Most often, accidents occur even during the construction of a house, since often designers do not take into account the need for additional strengthening of the pediment, which is subjected to increased loads from the wind, especially if any non-standard roof option is chosen, for example, a roof with three pediments.
The order of construction of gables
It does not matter how to make the gable of the roof - before or after the construction of the roof, since both options are associated with certain difficulties.
If the gables are assembled in advance, then the advantage is the absence of interference from the roof structure, such as, for example, a hip standard roof, but insufficiently carefully performed measurements can lead to the fact that the dimensions of the gable do not match the dimensions of the resulting roof - it will not reach it or, conversely, go beyond it.
If the laying of rafters on the pediment is provided, then in any case it is built first.
After the completion of the construction of the roof, the gables are erected in a limited attic space, which is not very convenient, but still used quite often.
In this case, the probability of an error in the dimensions of the gable is excluded, but if its dimensions are sufficiently large and it is planned to fill the upper part of the reinforcement belt using reinforced concrete cores, it is recommended to perform the gable in the first place.
Since the rafters act on the Mauerlat in both directions, it should be given sufficient rigidity in both the vertical and horizontal directions.
The most common is the Mauerlat, the section of which is 100x100 and above, a smaller size can lead to various problems that require various corrections in the future and lead to an increase in the total cost of construction.
Main loads on the gable walls
The main load on the gable wall in the horizontal direction is created by the wind.
When designing a building, the following factors should be taken into account:
- Roof type;
- Wind speed;
- Altitude above sea level;
- Building resistance to wind currents;
- Features of the region in which construction is underway.
When calculating these indicators, one should keep in mind the change in the geometry of the building during the construction process, as well as changes in the area of some structural elements under the influence of wind. For a finished building with a residential attic space, an aerodynamic coefficient of 0.7 is assumed.
The walls of the pediment during the construction of such a structure as hipped hipped roof equipped with triangular elements fluttering in the wind like sails, so the aerodynamic coefficient should not be 0.7, but from 1.4 to 1.6.
Production of gable walls
Width and height have a significant impact on the strength of gable walls. Smaller walls are stronger and more stable than thin high walls, which require additional support structures to prevent the wall from collapsing as a result of any minor external impact.
In modern construction, the issue of cracking and subsequent collapse of the erected gable walls associated with the use of light materials in the construction of the building, which are supplied in significant quantities, quite often arises.
The high popularity of such materials is due to their high thermal insulation performance, but their use makes the structure not protected from strong wind loads.
Here is an example of a comparison of old and modern houses:
- Brick walls were erected in old houses, the thickness of which ranged from 38 to 41 centimeters, in some cases the thickness was chosen 25-27 cm, but additional structures were used for strengthening, such as pilasters and cornices. The density of the material from which the gable walls were built was over 800 kg/m.
- In modern houses, two-layer walls are quite common, as the bearing part of which blocks of porous ceramics or cellular concrete are used. The thickness of two-layer walls is no more than 25 centimeters, and in the case of single-layer walls - from 36 to 44 centimeters. Today, buildings constructed from three-layer walls with increased resistance to wind loads, the thickness of which is usually from 39 to 54 cm, have the greatest strength.
In the case of windows or a balcony door in a gable wall, the risk of wind exposure to the wall increases significantly, as a result of which the total length of the joints should be carefully calculated, making it sufficient to successfully withstand external loads in the form of gusts of wind.
Giving gables additional rigidity
In order to give the gable wall additional strength, the most common are the following methods:
- The most time-honored method of reinforcing the gable wall is the construction of a dividing wall, the minimum thickness of which is 24 centimeters, erected perpendicular to the gabled wall in the attic. At the same time, the construction of a plasterboard wall or a thin partition will not provide additional rigidity to the gable wall.
- Quite successfully, elements such as pilasters or columns make it possible to give the building additional rigidity. But this method leads to difficulties in masonry and worsens the interior design of the room, so it is not widely used.
- For small buildings, a good way is to use a reinforced concrete frame reinforced with four rods with a diameter of 10 millimeters. The cross section of such a frame can be 250 centimeters, which will be enough to build a house in a region with standard wind loads.
Important: with increased wind loads, the strength attached to such a frame will be insufficient.
Strengthening the gables of the roofs will allow the built house to serve in all weather conditions for many decades, as well as ensure the reliability of the roof base and protection from various weather emergencies.
Performing a vapor barrier of the pediment
Finishing the roof pediment includes a vapor barrier designed to prevent the penetration of moist air flows from the interior into the thermal insulation material.
The steam film is installed directly under the inner wall cladding, which ensures moisture condensation directly on the film.
In order to prevent the accumulation of significant amounts of moisture, leading to the formation of streams of water flowing onto the floor along gable roof, it is necessary to provide a small ventilation gap to ensure continuous air circulation.
This gap also makes it possible to prevent water droplets from penetrating into the finishing material, causing damage to the interior finish.
Did the article help you?