Roof structures can be conditionally divided into flat and pitched. The former are most often used in public, industrial, and multi-story residential buildings, while the latter are used in the construction of private houses and cottages. A rafter system in a pitched configuration has many advantages, but also differs in a complex device. One of the most important elements of this system is the ridge node, on which the slopes are closed, supported by supports, Mauerlat and struts.
General information about the roof ridge
Under the ridge, roofers mean a whole system of structural elements that mate with the rafter system. Its base is formed by a horizontal rib of transverse slopes. This is the highest point of the house, which can perform several tasks. The main purpose of this site is to reliably close slopes and roofing. The ridge connects several rafter elements, also acting as a regulator of the microclimatic parameters of the roof in the under-roof space. In particular, through it the circulation of air flows is ensured, moisture is removed from the attic and the products of combustion of boilers and furnaces are removed. But in order to perform these functions, the ridge assembly should initially be provided with appropriate engineering devices. Mostly the ridge is used in gable roof systems, but a broken four-gang configuration when laying the roof in several levels can use this element.
Technical and construction device of the ridge
As already noted, the central link in the node is a horizontally located rib - this is a wooden beam of timber, on which slopes rest on different sides. In turn, the rafters for the slopes on the lower tier at the points of the ceiling are based on Mauerlat. Vertical support - the so-called headstock - acts as elements of power support for the ridge itself. They can also have side supports that increase structural stability.
A scheme of the roof truss system without vertical supports is also possible, but subject to increased horizontal support. In such constructions, the function of the uprights is performed by ligaments and puffs with struts that directly connect two slopes below the level of the ridge itself. In this case, the central beam 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 shifted from the center of the ceiling to the support along the perimeters of the outer walls.
Types of Roof Skates
The skate system can be made in different ways. As for the material of manufacture, in addition to the bar, metal profile rods can be used. Another thing is that they have many shortcomings (from a lot of weight to difficulties in installation), which is why it is often used wood lumber. The main differences are determined by the shape and design of the ridge site of the roof, which can be performed in the following options:
- Skate profile. The traditional version of the node docking two slopes. This is the same wooden beam, which allows you to endow the top point of the rafter 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.
- Mortise horse. Non-standard rafter support unit, which is used for hip, that is, four-pitched roofs. The central bearing bar literally cuts into the ramp, forming in some way a branch of the ridge from the main rafter system.
Types of roofing skate
If on the back side the ridge is mated with the elements of the rafter system, then the roof covers it from the outside, the choice of which is also important. The following skating options are relevant today:
- Metal tile. The material is good for its durability and aesthetic benefits. If you choose the right type of external polymer treatment, you get comprehensive protection from rain, sunlight, wind and other negative factors. The only disadvantage of metal is the high price.
- Decking. Galvanized steel sheets, which are also known for their high service life (30-40 years) and mechanical reliability. But, choosing a professional sheet for the ridge node, it is necessary to take into account possible load restrictions. On 1 m 2 this roof gives from 5 to 10 kg on average, which is not suitable for every rafter system.
- Slate. A budget solution that is profitable for its versatility and practicality. But due to the low strength and lack of decorative qualities, this option is often used for hozblok constructions.
As an alternative, a roof based on ondulin, bitumen and flanges can be considered, but in conjunction with the ridge, these coatings more likely serve as the basis, and not the complement. Such systems are supplied in special kits, which may also include devices for snow protection, gutters, chimneys, etc.
Calculation of the ridge knot
During the development of the project, the roofer must determine the optimal height of the ridge. For this, the technical parameters of the run beam located in the center of the rafter system are required. This data will depend on the width of the house. Also, the angle of the slopes, which varies from 5 to 60 degrees, is taken into account in the calculations. Knowing the width of the house (the distance from the opposite Mauerlat, 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 the ridge node of a pitched roof with an angle of 30 degrees for a house with a width of 6 m, 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
In private houses, roofs have many functions related to the engineering of the entire building. Obviously, the skate, to varying degrees, will have to interact with individual systems. An expanded list of additional elements covers the following devices:
- Stubs. Required for installation of additional roof elements and protection of pitched joints.
- Snow holder. A barrier for snow masses, which minimizes the load from precipitation on the roof and the rafter system as a whole.
- Wind bar. A metal plate designed for lateral protection of the ridge node of the rafter roof from precipitation, wind and accidental mechanical shock.
- Cornice. Also, a variant of the protective element, which is installed on a wooden cornice board under hydro and thermal insulation coatings.
In addition to the main function in the selection of additional skating devices, 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 also to perform the general composition in a single material. This nuance is important from the point of view of reliability of installation.
Skate Mounting Technology
To the device of the ridge go after the installation of the roof on the surface of the slopes. Parts are delivered to the roof with a rope or using a winch mechanism. First of all, a beam with a cross section of 7x9 cm is installed. On both sides, the lathing elements in the form of wooden planks are attached to it. It is more convenient to carry out these operations with the central ridge plank having a rounded surface, therefore, if you wish, you can perform manual processing of the timber with a jigsaw or grinding and chip machines. To prevent negative biological processes, it will 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 site, as a rule, is provided with a lining of insulation and protection against mold and fungus. The fastening of the tiles in this part is made directly to the timber.
Fixation of the ridge structure
Mechanical fastening of the elements of the ridge structure can be performed in various ways. A typical fixation model is implemented in the following sequence:
- Mounting holes are drilled on the main components of the assembly (only on the flat sides).
- Before installing the fasteners, the fitting and joining of parts with an overlap of 10 cm is completed.
- For a semicircular ridge, a connection is made along the stamping lines.
- Rafter trusses under the ridge node are mounted using self-tapping screws with nails or by the method of laying in a groove. The main thing is that by the time of installation the slope angles from the ramp were correctly calculated.
- To increase the strength of the structure, as an addition, a skate board is mounted above the level of the crate trusses.
Deflector ridge device
Maintaining dryness in the under-roof space is the most important condition for ensuring the optimal condition of the rafter system. The ridge deflector just contributes to the removal of steam and moisture from under the roof and the attic, avoiding rainfall inside. 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, plastic deflectors are ergonomic and easy to install. From the roofer, it is only necessary to mount a segment in the ridge assembly with the air exhaust channel and, if necessary, provide it with auxiliary elements like a pipe and a diffuser. Further, the adjacent joints of the joints of the roofing segment with the deflector are additionally reinforced with hardware, and the gaps are sealed with foam or building silicone.
Skate Maintenance Tips
If the device of the rafter system used high-quality wood with normative characteristics of moisture without physical defects, then special maintenance measures are not required. It is enough to process the elements of the ridge site of the roof once every 2-3 years with protective impregnations with refractory and antifungal functions. You should also periodically monitor external protective devices in places of pitched joints and on gables.
Conclusion
The skate, although it occupies the highest point in the rafter system, but not only it determines the technical and operational characteristics of the roof. The quality of its functional processes will to a large extent depend on the structural support, the used insulators, substrates and roofing. It will be right to consider the ridge node as part of the roof supporting 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 subroofing niche and the stability of the position of the slopes. Another thing is that in different configurations of the device of this node, different requirements for functionality and technical reliability will be presented to it.