Roof structures can be conditionally divided into flat and pitched. The former are more often used in public, industrial and multi-storey residential buildings, and the latter in the construction of private houses and cottages. The truss system in a pitched configuration has many advantages, but it also differs in a complex device. One of the most critical elements of this system is the ridge knot, on which the slopes are closed, supported by supports, Mauerlat and struts.
Roof ridge overview
Under the ridge, roofers mean a whole system of structural elements that mate with the truss system. Its basis is formed by a horizontal rib of transverse slopes. It is the highest point of the house and can serve multiple purposes. The main purpose of this node is to reliably close the slopes and roofing. The ridge connects sever altruss elements, also acting as a regulator of the microclimatic parameters of the roof in the under-roof space. In particular, air circulation is provided through it, moisture is removed from the attic space and combustion products of boilers and furnaces are discharged. But to perform these functions, the ridge assembly must initially be provided with appropriate engineering devices. The ridge is mainly used in gable roof systems, but a broken four-slope configuration when laying the roof in several levels can use this element.
Technical and structural device of the skate
As already noted, the central link in the knot is a horizontally located rib - a wooden beam made of timber, on which the slopes are supported from different sides. In turn, the rafters for the slopes on the lower tier at the points of the ceiling are based on the Mauerlats. As elements of the power support of the ridge itself, vertical supports - the so-called grandmas - act. They can also be fitted with side braces which increase the stability of the structure.
It is also possible to design a roof truss system without vertical supports, but subject to increased horizontal support. In such structures, the function of vertical racks is performed by ligaments and puffs with struts that directly connect two slopes below the level of the ridge itself. The central beam in this case is supported only by the force of two slopes, which in turn give even more load on the Mauerlat beams. In other words, part of the weight is shiftedfrom the center of the floor to the support along the perimeters of the outer walls.
Types of roof ridges
The ridge system can be made in different versions. As for the material of manufacture, in addition to timber, metal profile rods can be used. Another thing is that they have many disadvantages (from heavy weight to difficulties in installation), so it is wood lumber that is most often used. The main differences are determined by the shape and design of the ridge roof unit, which can be made in the following versions:
- Redge profile. The traditional version of the junction of two slopes. This is the same wooden beam that allows you to endow the top point of the truss system with all the necessary functional components.
- Semicircular plank. Actually, this is a variation of the classic wooden profile, but in a more aesthetic form. You can notice the external features of this solution on the gables of the house.
- Cut-in skate. A non-standard rafter support unit, which is used for hip, that is, hipped roofs. The central bearing bar literally cuts into the slope, forming in some way a branch of the ridge from the main truss system.
Types of ridge roofing
If from the back side the ridge mates with the elements of the truss system, then outside it is covered with a roof, the choice of which is also important. To date, the following options for ridge coverage are relevant:
- Metal tile. The material is good both for its durability and aesthetic advantages. If you choose the right type of external polymer treatment, you will get comprehensive protection from precipitation, sunlight, wind and other negative factors. The only disadvantage of metal tiles is the high price.
- Profiling. Metal sheets made of galvanized steel, which are also famous for their high service life (30-40 years) and mechanical reliability. But, when choosing a profiled sheet for a ridge knot, it is necessary to take into account possible load restrictions. For 1 m2 this roof gives from 5 to 10 kg on average, which is not suitable for every truss system.
- Slate. Budget solution, which is beneficial for its versatility and practicality. But due to low strength and lack of decorative qualities, this option is more often used for buildings of the utility block.
As an alternative, you can consider a roof based on ondulin, bitumen and flanges, but in conjunction with the ridge, these coatings serve as a basis rather than an addition. These systems come in special kits that may also include snow guards, gutters, chimneys, etc.
Calculation of the ridge knot
In the process of developing a project, the roofer must determine the optimal height for placing the ridge. This requires the technical parameters of the running beam, located in the center of the truss system. This data will depend on the width of the house. The calculations also take into account the angle of the slopes, whichvaries from 5 to 60 degrees. Knowing the width of the house (the distance from the opposite Mauerlats, from which the slopes extend) and the angle of the roof, you can determine the height from the attic floor to the top of the roof. For example, in the design of a 30-degree pitched roof ridge assembly for a house 6 m wide, the height will be approximately 3.5 m. In the calculation process, a standard coefficient of 0.59 will be used (used for roofs with a 30-degree slope), which must be multiplied by 6 m.
Skate accessories
In private houses, roofs have many functions related to the engineering of the entire building. It is obvious that the skate will also have to interact with individual systems to varying degrees. The expanded list of additional elements covers the following devices:
- Stubs. Required for installation of additional roofing elements and protection of pitched joints.
- Snow holder. A barrier for snow masses that minimizes the load from precipitation on the roof and truss system as a whole.
- Wind bar. Metal plate designed for lateral protection of the ridge roof truss assembly from precipitation, wind and accidental mechanical shocks.
- Cornice. Also a variant of a protective element that is installed on a wooden cornice board under hydro- and heat-insulating coatings.
In addition to the main function, when choosing additional ridge accessories, it is desirable to take into account the stylistic nuances of the choice. Moreover, designers advise not only to give preference to elements with the same texture and texture, but alsoperform a common composition in a single material. This nuance is also important from the point of view of installation reliability.
Ride mounting technology
To the device of the ridge they pass after the completion of the laying of the roof on the surface of the slopes. Details are delivered to the roof with a rope or using a winch mechanism. First of all, a beam with a section of 7x9 cm is installed. On both sides, elements of the crate in the form of wooden planks are attached to it. These operations are more convenient to perform with a central ridge bar, which has a rounded surface, so if you wish, you can manually process the beam with an electric jigsaw or grinders. To prevent negative biological processes, it would be useful to isolate the installed wooden elements with roofing material, which will also perform the functions of steam and moisture protection. By the way, the back side of the metal tile for the ridge knot, as a rule, is provided with a lining of insulation and protection against mold and fungus. The tile elements in this part are fastened directly to the timber.
Fixing the ridge structure
Mechanical fastening of the elements of the ridge structure can be performed in different ways. The typical fixation model is implemented in the following sequence:
- Mounting holes are drilled on the main elements of the assembly (only on the flat sides).
- Before installing the fasteners, the fitting and joining of parts with an overlap of 10 cm or more is completed.
- For a semicircular ridge, a connection alongstamping lines.
- Rafter trusses under the ridge knot are fastened with self-tapping screws with nails or using the method of laying in a groove. The main thing is that by the time of installation, the angles of inclination from the slope are correctly calculated.
- To increase the strength of the structure, as an addition, a ridge board is mounted above the level of the crate trusses.
Skate device with deflector
Maintaining dryness in the under-roof space is the most important condition for ensuring the optimal condition of the truss system. The ridge deflector just helps to remove steam and moisture from under the roof and attic space, preventing precipitation from entering. In the installation of this element, it is desirable to use a roof segment with a ready-made ventilation duct. In the same metal tile, ergonomic and easy-to-install plastic deflectors are provided. The roofer is only required to mount a segment with an air outlet channel into the ridge assembly and, if necessary, provide it with auxiliary elements such as a pipe and a diffuser. Further, the adjacent joints of the roofing segment with the deflector are additionally reinforced with hardware, and the gaps are sealed with mounting foam or construction silicone.
Skate maintenance tips
If the truss system used quality wood with standard moisture characteristics without physical defects, then special maintenance measures will not be required. It is enough once every 2-3 years to treat the elements of the ridge assembly of the roof with protectiveimpregnations with refractory and antifungal functions. You should also periodically monitor the external protective devices at the pitched joints and on the gables.
Conclusion
Although the ridge occupies the highest point in the truss system, it is not only it that determines the technical and operational characteristics of the roof. The quality of its functional processes will depend in no small measure on the structural support, insulators, underlays and roofing used. It will be correct to consider the ridge assembly as part of the roof support system. Does this mean that little depends on him? Of course no. During operation, the structural characteristics of the ridge will determine the microclimatic properties in the roof niche and the stability of the slopes. Another thing is that in different configurations of the device of this node, it will have different requirements for functionality and technical reliability.
