The positive effect of wood has always been appreciated by people, which is why we are still seeing the use of this material both for the installation of walls and for the construction of roof structures. Wooden houses are beautiful, practical and comfortable. The final stage of construction of any building is the roof, so keep in mind how a wooden roof is created by hands and how long it will take.
Wood, the first material used in the construction of residential buildings, is becoming popular with modern craftsmen. A few decades ago, the cost of such a roof was the lowest, and the installation was the easiest. Now things are different: the material is very expensive and it takes a lot of technical training and experience to place it.
As before, a wooden roof with all the rules will allow you to get an exclusive design that will last for many years.
Description of wooden roof installation
Depending on the selected materials, the installation technique and the roof mast are determined.
The hardest part will probably be working with the cup. If the builder is inexperienced with these types of parts, then a wooden roof by hand may cause some problems or not work at all.
Outside the material are small plates (width - 10-15 cm, length - 40-70 cm), which are chopped manually or by hand. Due to the roughness formed in the cut, moisture is absorbed, so the material is of great importance with the presence of natural fibers.
On one longitudinal side, the plate is cut until the thickness reaches 3-5 mm, and on the other side, a wedge groove is cut with a depth of 10-12 mm, as shown in the figure. The gon consists of coniferous, brick and oak. A box (rod or rod with part 40×40 mm or 50×50 mm) is used as the basis for laying the lid. Wood roof calculation is done by fixing a shaft or rods with a shaft length of 1/3 inch and solid foil can be formed from the panels.
Horizontal types of materials are arranged in accordance with one direction of the gutters and fix the narrow ends of the tiles in them. Once the slabs are level on the roof, they are squashed with the top edge against the wood. Nails must be inserted into the box at least 20 mm. The choice of nail depends on the type of wood, so cedar and larch are fixed with brass, while other types of wood can be fixed with galvanized nails.
How reliable a wooden roofing device is depends on the layer of pebbles:
- For pavilions and commercial buildings, layers are enough where the new line is located, covering half of the previous panel (see "How to make wood tiles, the roof of the device").
- The construction of residential buildings is carried out on the basis of three layers, and the new line is on top of the previous one.
- Buildings requiring high quality and reliability may contain a four-layer structure, with new rows located on top of the previous ¾.
When laying, the upper slabs are located at the bottom to the middle of the previous row.
The patchwork definition (roof connections with a concave end) acts like a fan, which, the narrow sides of the panel, is sheared down defined, so that the tiles become trapezoidal.
Before building a wooden roof, all parts are pre-treated with antiseptic agents, and fire-fighting use a fire-resistant compound. Also read: "Device on the roof of the house."
The installation of proportions and filmmaking is carried out similarly to a cup. Since the boards are short (about 20-40 cm), the distance between the glow beams decreases. The elements do not have common grooves, so they fit into the connection at the joint, taking into account that the wood can rotate over time (with a distance of 3-5 mm between the plates).
In wet weather, the joints of the wooden structures of the roof will exactly match each other, and in warm weather they will create optimal conditions for the ventilation of the wood.
The construction of a wooden roof is in most cases larch, which is distinguished by:
- high density and resin content, corrosion and insect protection;
- the duration of the operation;
- attractive wood structure;
- low price.
Characteristics of wood chip and tile roofing
Such material is embedded in three or four layers that overlap both vertically and horizontally.
A length of shingle is attached to a wooden roof - its patterns are not much different from other types of structures, like shingles. Neighbors should be closed up to 25-30 mm.
The new horizontal layer must be installed in such a way that the joints of the two lower belts are covered by one of the upper ones. Each shield to wear the nail shield struck 70×1.5mm, followed by the stitching of the wooden corner comb.
The construction of slate roofing follows the same technology as shortened planks.
Usually they are offered in lengths from 40 cm to 10 m, width 9-13 cm, thickness 3-5 mm. The dimensions of the chips are somewhat smaller: length - 40-50 cm, width - 7-12 cm, thickness - 3 mm. Of these features, the chips are attached to the box in increments of about 15 cm, the holder - from 30 cm. Both materials are very light, so they should be at least 40 x 40 mm.
Roof covering - various options, see video:
Roof Features
If a do-it-yourself wooden roof is to be built, this will be the easiest and most affordable option for many just above the roof.
However, this coating will serve to reduce the order, as a result of the destruction of the natural structure of the wood when sawing. If you want to preserve the properties of the field, you must prepare slabs separating the logs in length, that is, in the same direction as the fibers of the material. Such coating will be carried out with due care for at least a hundred years.
When building the roof of a wooden house, there are two ways of laying theses: transverse and longitudinal. The cross-section method is the simplest wooden roof device, but it is only suitable for temporary construction.
Nail plates, like any other coating, from the bottom up with a 5 cm coating of the bottom row of the top.
The difference in the longitudinal method has several styling options:
- in the form of a two-layer coating - the plates are fixed with the top layer, which moves to the lower part to the middle of the plate, and for swelling it remains 0.5 cm;
- in the first row, the plates are spaced at 50 mm intervals, the elements on the next row must be covered up to 50 mm from each previous plate;
- when using a latch - the bottom line is solid, you must use narrow strips to cover the joints, which should be 50 mm.
Regardless of the method that restores wooden roofs, to ensure that the top nail is securely attached to each row on the slab in increments of 600-800 mm in thickness from 19 to 25 mm, the cross section of the beam is 60x60 mm.
Before choosing a material, read: "How to choose a roof for a house."
1. Description of the roofing materials used
2. What elements does the roof consist of
3. Features of load-bearing structures
During the construction of wooden houses, the task is to rationally combine the aesthetics and practicality of the roof structure.
Among the large selection of materials, far from everything is suitable here, which significantly complicates the construction technology.
Following the main requirement, it is necessary to pay attention to ensuring that the roof structure of a wooden house looks harmoniously against the background of the entire building. Wooden houses have always been in great demand among connoisseurs of environmentally friendly and natural materials, and the correct processing of the log allows you to achieve good thermal insulation, ease of installation and reliable fastening of suspended structures.
A significant disadvantage of wood is its deformation during temperature fluctuations, especially changes in humidity levels, which must be taken into account when choosing one or another lumber.
Particular attention is paid to the order of assembly of window and door openings, shutter speed for shrinkage of the log house. The problem areas include a wooden roof - its construction is being built according to certain rules (read: "The device of a wooden roof - features of the coating"). As already mentioned, a special material is selected for it, it is installed under certain conditions, during operation it requires increased control than, for example, when building a roof on a stone building.
The shrinkage coefficient of raw logs and timber is 10%, raw profiled timber reaches about 5%, dried and glued timber - up to 3%. Based on these values, two values are noted in the construction project of wooden houses - before the material has sat down, and after that.
As a rule, the roofs of such houses are pitched, which is indicated even in the snip - wooden roof structures are flat and shed are considered impractical and outwardly unattractive.
A large selection of pitched configurations allows you to choose what the future home owner likes, for example:
A pitched roof has a number of advantages over other types of roofs:
- has the best thermal insulation of wooden floor trusses;
- under it you can equip the attic;
- cheaper roofing is suitable for it;
- snow masses descend from the roof as they accumulate;
- rainwater rolls off faster;
- you can make long roof overhangs, so that precipitation will be removed far from the walls.
Description of the roofing materials used
The construction or reconstruction of the roof of a wooden house is being carried out using any of these coatings:
- built-up materials on bituminous mastic, for example, euro tiles;
- rolled deposited materials;
- ceramic and metal tiles;
- slate;
- ondulin.
The use of euroslate and corrugated board for wooden houses will lead to noise from the rain, and due to the reduced waterproofing properties, constant repair of the roofing pie will be required.
Rafter system nodes - how to make a reliable roof?
The exotic option includes the arrangement of the roof in the form of a longitudinal overlap of the edged board, or "historical" materials (thatched roofs, reeds). However, the so-called wooden roof, the design of which practically does not differ from traditional options, will be relevant in the locations of eco- or ethno-villages close to nature. See also: “Reed roof”.
What elements does the roof consist of?
The roof is assembled from several interconnected components, pictured :
- Slopes - inclined roof surfaces, which can be flat or curved.
- Ridge - the upper longitudinal rib at the junction of the slopes.
- The ribs of the slope, represented as a protruding corner at the intersection of the slopes.
- Endova, also called a groove, which is a concave intersection of slopes.
- Eaves overhang - a slight protrusion of the roof beyond the frame (at the final stage, we hem the roof eaves with a finishing material).
- Gable overhang - part of the roof, hanging over the wall.
- Gutter.
- Downpipe.
- Chimney.
Regardless of the choice of roof covering, the structure of the roofing cake must be completely preserved.
For the crate are taken: for metal materials and slate - bars or boards, for tiles only boards.
If materials on bituminous mastic are used, then the crate is laid in a continuous sheet. In the case of using an attic or attic for living, interior decoration is also performed. But in any case, the order of laying the layers of the cake must be observed.
So, if the owner of the house independently builds wooden roof structures, then you need to adhere to the basic requirements:
The truss system of a wooden house, in detail on the video:
Features of load-bearing structures
Before the construction or reconstruction of wooden roofs begins, a scheme for its construction is carefully selected. The pitched roof is fastened to certain rafters. The most common are the layered and hanging structures, differing only in that in the first version there is an intermediate support, or a support for an internal load-bearing wall or partition.
The support should not be located further than 6.5 m from the outer wall, and the second support helps to increase each run - the distance from the middle support beam and the outer wall is up to 15 m. Mauerlat (rafter beam) in a wooden house is constructed from the upper wall row of logs .
Hanging rafters are supported only by walls subjected to bursting force.
For beginners who have no idea about such installation, it is better to order a finished house project from a special company. Typical and universal designs of wooden roofs will be offered there, and an individual option can be developed (read: “The device of the roof of a wooden house: which roof to choose”).
If raw lumber is used in construction, then it is important to let the building settle, while the arrangement of the node should be with special “sliding” elements.
As soon as the shrinkage of the rafters begins across the location of the beam, then with the help of such a wooden roof device it will be possible to maintain their longitudinal binding.
By analogy with this, the rafters are also fastened next to the ridge.
The result of such actions will be that even with significant shrinkage, the wooden roof structures will remain in their original place and will not deform.
Summing up, one should pay attention to the rather complex structure of wooden houses, the design and installation of which requires high professionalism. Beginners who do not have certain skills cannot cope with the work themselves. As for the choice of materials, varieties of roofs, everything is limited only by the budget of the owner of the house.
Read also the article: "Plate roofs - a device."
Do-it-yourself hip roof: the construction process
The roof shed is ready.
Wooden roof - ecology, economy and reliability
It's time to make the roof truss system. Consider the step by step process of its installation.
Consider the process of erecting and installing a hip roof (four-pitched roof), which consists of corner, intermediate and auxiliary rafters. The work is not very difficult, it can be handled by a person without experience. The main thing is to make the right calculations.
The construction of the hip roof begins with the laying of the Mauerlat, but since we have a log cabin under the roof, the upper log will serve as the Mauerlat.
Laying floor beams
So, it's time to mount intermediate floor beams, with a section of 10 by 20 centimeters and an intermediate step of 0.5-0.6 meters (there may be other values).
Attaching them to the beam will not be difficult.
It is enough to lay the bars on top of the logs and fix them with metal corners.
It is possible to make cuttings in logs. To do this, you first need to make an accurate marking of future holes, then take a chainsaw with a sharp chain and make cuts with a depth equal to half the log section.
The height of the grooves should be 3 centimeters higher than the height of the beams in order to align them if necessary.
When the cuts are made, armed with a chisel and a hammer, you need to bring the matter to mind, giving the holes the desired shape.
Be sure to check the horizontal beams by level.
Before laying the beams, their ends must be wrapped with pieces of eurofoam (insulation) soaked in an antiseptic solution, then additionally fix the beams with metal squares.
Installation of the skate
First you need to do the markup.
To do this, divide the gable walls in half (take the dimensions as accurately as possible).
Set aside the resulting size (from the center to the extreme wall) on the wall perpendicular to the gable, on both sides.
Similarly, repeat the procedure on the opposite side of the hip roof.
The distance between the lines will be equal to the length of the skate, the racks of which are installed at the intersection of the "squares".
Rack installation
For vertical racks we will use boards with a section of 5 by 15 centimeters, for a ridge - 5 by 20 cm.
Racks are set strictly vertically and supported by temporary braces on both sides.
Attached with self-tapping screws.
There should be two boards in one rack.
Between the vertical posts (between two boards of one vertical post) a ridge beam is installed and fastened with bolts. Additionally, a spacer can be mounted between the vertical posts.
Rafter installation
Rafters must be mounted on the installed ridge run. For this purpose, boards with a section of 5 by 15 centimeters are used (you may have others, depending on the calculations).
They are laid in increments of half a meter on the ridge run from both sides with an overlap. Then the boards are carefully cut at the top with a saw so that they can be joined end-to-end. The rafter legs are joined with metal profiles and self-tapping screws.
In the lower part of the hip roof, the rafters are installed on the mauerlat by cutting, which is done at an angle of 90 degrees.
It rests on the upper log and is attached to it with metal corners using self-tapping screws or nails.
You can also make small grooves on the log, insert the rafter legs into them and fix them in the same way.
The length of the boards should be such that the overhang over the eaves is at least 30 centimeters.
This is how all ridge rafter legs are installed.
After the installation is completed, the installation of the corner rafters begins.
Installation of corner rafters
The corner rafters are mounted first, which run along the center of the pediment. The section can be left the same.
Their length can be calculated using the Pythagorean theorem.
But you can simply place a temporary board between the ridge and the center of the gable wall beam and measure it.
Then add from 30 to 50 centimeters to the resulting value, which will “go for take-away”.
On the board, you need to prepare another one, on the opposite side, and then fix both to the ridge and the Mauerlat below. Boards are attached to the Mauerlat by cutting down.
Similarly, rafters are prepared and mounted on the four corners of the hip roof of the log house with their own hands.
Under all rafter legs, racks must be installed near the Mauerlat.
Installation of intermediate rafters
It remains only to install intermediate rafters.
To do this, the walls are marked with the selected step so that there is always a right angle between the marks on adjacent walls. At the intersection of two lines, a mark is made on the corner rafter.
Next, all distances are measured, rafter legs of the required length are prepared, taking into account the eaves overhang, and they are installed.
To attach the intermediate rafters of a floating roof for a log house to the corner ones, their ends must be cut at an angle of 45 degrees and fastened with bolts.
To simplify the calculations, it is possible to nail a board between the corner rafter legs and “dance” from it.
If the length of the boards is not enough, they can be spliced in various ways.
When all the rafters are installed, it is necessary to mount cornice boards around the perimeter of the hip roof, and then proceed with laying the battens and roofing material.
The type of lathing for the hip roof of a log house depends on what roofing material is planned to be used.
If soft roofing materials are used, for example, shingles, then the base must be solid.
Under hard materials, a sparse crate is made.
The step of the lathing also varies depending on the material for the roof.
The required pitch value is usually indicated by the manufacturer of the roofing material.
When installing a roofing pie, it is imperative to use insulation, vapor and waterproofing. You can read about how to install a certain type of roofing on our website in the relevant articles. The sequence of work is detailed there. To simplify the calculation of hip roof elements, you can use programs.
Hip roof, truss system
Terms used in the construction of wood veneers
- The rafter is the load-bearing part of the roof, which includes multi-layer supports, buttresses and vertical columns supported by Mauerlat.
- Skobel is part of the gorge.
- Mauerlat, presented as a support for several rafters, or in other words, on a bar placed at the top of the wall, evenly distributes them to the roof load, it is important to understand why you need a mauerdat.
- Tightening - A rail that is horizontally positioned to connect roof tiles and reduce horizontal impact on them to ensure stability on the roof, also used as a holder.
- Headstock - strengthens the scissors, sets: the lower part - is tightened; up - as support for the rafters.
- The spacer is attached as a connecting element between the logs.
- The hanger is in the form of an inclined beam, which is used to support the beams of wood that are adjacent to the horizontal parts (columns and pillars).
- The horse is horizontally mounted on the roof of the raid.
During the construction of wooden roof hinges can be divided into several groups:
- connecting legs with Mauerlat;
- connecting legs and elements of a wooden base for the roof, which makes the structure more solid and durable;
- A knot with flat parts is connected by stretching out from it.
Depending on the desired result, the rafters are connected to the Mauerlat with a rigid or sliding knot.
It should be noted that in some cases a rigid installation can even destroy the structure, as in the picture, since the weather conditions are favorable for pressing and opening the wood, but due to the rigid connection of the nasson system, it can deform the bearings of the wall under heavy load.
Features of hard knots
A solid wood roof assembly has the following shape:
- The cutting is done at a depth of one third of the panel on the shoulder of the shoulder.
The machines should then be attached to the Mauerlat with nails so that two of them hit at a slight angle on the side of the rafters and one hits in the vertical direction.
- For a 1 m rafter, the lifting timber is put in place as a support for the mauerlat, the side fixing screws are screwed in with metal corners in this position.
Characteristics of sliding knots
The connection of the elements of the nasal system is carried out using sliding knots.
The use of suspended rafters is useful in round timber roof construction where the spine pole is used as a support for the rafters and there is no spacing between loadbearing walls.
Newly built wooden farmland will be saved within a few years, so using rigid fixtures to permanently move the truss will cause the walls to warp.
To avoid such problems, wooden roofs are scissor system components that must be determined with a free movement permit, built as follows.
The curved leg, using a pre-made saw, rests on the Mauerlat and is tied (two on each side, the third vertical).
- Metal tiles dropped from the wall are attached to metal corners that connect them to the mauerlat.
- Metal structures are determined by the "trace" method (see "Metal Truss, Cons and Advantages").
- Support of the foot in the Mauerlat should be carried out taking into account the movement of these systems in relation to each other.
- Roofs are not damaged in the event of a gale, the binding of braces, shepherds and spacers to the hanging rafters is done with clips and clamps; there are also twisted wire rolls around the leg.
How to connect round legs
If the roof tension is large enough, special attention should be paid to the wooden roof hinges, as well as the columns, which will need to be expanded to the desired dimensions using one of the suggested methods.
How to connect pile rafters in construction
The developers pay special attention to the comb top connection mode.
The main findings of the scissor system, detailed in the video:
The difference between teeth and "tip"
- Due to its high strength, the spike connection is excellent for wooden construction.
The tip is the part that attaches to the journal, which connects to the socket, tongue, or ear of the second diary. The size and shape of these two elements must match each other.
- The tooth is connected to the stepped cut one day and the inscriptions the next. As in the case of the previous method, for a snug fit of wooden roof structures, it is necessary to take into account the ratio of their size and shape.
If the developer is building a wooden roof, when connected to the roof elements, the knitting legs must be secured with screws, screws, clips and screws.
The diameter of the hole should be 1 to 2 mm of fasteners, and the brackets are fixed on both sides.
When using a screw connection on the scissors, a screw located at the top of the structure is used and the groove is cut at half the thickness of the log.
Only if these requirements are met will the journals closely coordinate with each other. In the next step, the assembly is attached to the screws and special brackets.
A flat roof can be avoided evenly - the nodes can be of any shape, with the same scissors. Experienced builders recommend template design so that all frames and cuts are the same size (see: "Building a Wooden Roof - Cap Specifications").
The description of the entire roof construction system is provided by the most complete presentation, but the wooden cart, which is quite difficult for beginners, requires a professional approach. Also read: "Building the roof of a wooden house: which roof should you choose."
When designing any residential building, architects pay special attention to the roof, as it performs not one, but several functions at once, depending on its design features. It must be said that not all future homeowners are satisfied with the usual gable roof, although it can be called the most reliable, since it has only two pitched planes and one joint between them. Many are attracted to more complex designs that add a special appeal and originality to the structure. Other, more practical homeowners prefer attic structures that can simultaneously serve as a roof and a second floor.
The basis of any roof is an individual truss system, which has its own design features. Making the choice of the desired roof frame will be much easier if you figure out in advance which ones types and schemes of truss systems used in building practice. After receiving such information, it will become more clear how complex such structures are in installation. This is especially important to know if the roof frame is supposed to be built independently.
The main functional tasks of truss systems
When arranging pitched roof structures, the truss system is a frame for covering and for holding materials of the "roofing pie". With proper installation of the frame structure, the necessary conditions will be created for the correct and non-insulated types of roofs that protect the walls and the interior of the house from various atmospheric influences.
The roof structure is also always the final architectural element of the exterior design of the building, supporting its stylistic direction with its appearance. Nevertheless, the design features of the truss systems must first of all meet the requirements of strength and reliability that the roof must meet, and only then - aesthetic criteria.
The frame of the truss system forms the configuration and angle of inclination of the roof. These parameters largely depend on the natural factors characteristic of a particular region, as well as on the desire and capabilities of the homeowner:
- The amount of precipitation in different periods of the year.
- Direction and average wind speed in the area where the building will be erected.
- Plans for the use of space under the roof - the arrangement of residential or non-residential premises in it, or using it only as an air gap for thermal insulation of the premises below.
- Variety of planned roofing material.
- Financial capacity of the homeowner.
Atmospheric precipitation and the strength of wind currents give a very sensitive load on the structure of the roof. For example, in regions with heavy snowfalls, you should not choose a truss system with a small angle of inclination of the slopes, as snow masses will linger on their surface, which can lead to deformation of the frame or roofing or leaks.
If the area where the construction will be carried out is famous for its winds, then it is better to choose a structure with a slight slope of the slope so that the sharp gusts that occur do not rip off individual elements of the roof and roof.
The main elements of the roof structure
Details and nodes of truss systems
Depending on the type of truss system chosen, the structural elements used can vary significantly, however, there are details that are present in both simple and complex roof systems.
The main elements of the pitched roof truss system include:
- Rafter legs forming roof slopes.
- - a wooden bar fixed on the walls of the house and serving to fix the lower part of the rafter legs on it.
- The ridge is the junction of the frames of two slopes. It is usually the highest horizontal roof line and serves as a support on which the rafters are fixed. The ridge can be formed by rafters fastened together at a certain angle or fixed on a ridge board (run).
- Sheathing is slats or beams mounted on rafters with a certain pitch and serving as the basis for laying the selected roofing material.
- Retaining elements, where you can take beds, girders, racks, struts, ties and other parts, serve to increase the rigidity of the rafter legs, support the ridge, link individual parts into a common structure.
In addition to the above structural details, other elements can be included in it, the functions of which are aimed at strengthening the system and optimal distribution of roof loads on the walls of the building.
The truss system is divided into several categories depending on the different features of its design.
attic space
Before proceeding to the consideration of different types of roofs, it is worthwhile to figure out what an attic space can be, since many owners successfully use it as utility and full-fledged living quarters.
The design of pitched roofs can be divided into non-attic and attic. The first option is called just that because the space under the roof has a small height and is used only as an air layer that insulates the building from above. Such systems usually include or have several slopes, but located at a very slight angle.
The attic structure, which has a sufficiently large ridge height, can be used in different ways, be insulated and not insulated. These options include attic or gable version. If a roof with a high ridge is chosen, then it is imperative to take into account wind loads in the region where the house is built.
Slope slope
To determine the optimal slope of the roof slopes of the future residential building, first of all, you need to look at the already built low-rise neighboring houses. If they have been standing for more than one year and steadfastly withstand wind loads, then their design can be safely taken as a basis. In the same case, when the owners set the goal of creating an exclusive original project, unlike the buildings standing nearby, it is necessary to familiarize yourself with the design and operational features of various truss systems and make appropriate calculations.
It should be borne in mind that the change in the tangent and normal values of the wind force depends on how large the slope of the roof slopes is - the steeper the angle of inclination, the greater the importance of the normal forces and the smaller the tangents. If the roof is sloping, then the structure is more affected by the tangential wind load, since the lifting force increases on the leeward side and decreases on the windward side.
Winter snow load should also be taken into account when designing the roof. Usually this factor is considered in combination with the wind load, since the snow load on the windward side will be much lower than on the leeward slope. In addition, there are places on the slopes where snow will definitely collect, giving a big load on this area, so it should be strengthened with additional rafters.
Roof slopes can vary from 10 to 60 degrees and must be selected not only with regard to the consolidated external load, but also depending on the roofing that is planned to be used. This factor is taken into account because roofing materials differ in their mass, their fixing requires a different number of elements of the truss system, which means that the load on the walls of the house will also vary, and how large it will be, also depends on the angle of the roof slope. Equally important are the features of each coating in terms of resistance to moisture penetration - in any case, many roofing materials need one or another slope to ensure the free flow of storm water or melting snow. In addition, when choosing a roof slope, you need to think in advance how the process of cleaning and repair work on the roof will be carried out.
When planning this or that angle of the roof slopes, you need to know that the fewer joints between the sheets of the coating, and the tighter they are, the less you can make the slope of the slope, of course, if it is not supposed to arrange a residential or utility room in the attic space.
If a material consisting of small elements, for example, ceramic tiles, is used to cover the roof, then the slope of the slopes must be made steep enough so that water never lingers on the surface.
Given the weight of the roofing material, you need to know - the heavier the coating, the greater the angle of the slopes should be, since in this case the load will be correctly distributed to the rafter system and load-bearing walls.
The following materials can be used to cover the roof: either a profile sheet, galvanized steel, corrugated asbestos-concrete and bitumen-fiber sheets, cement and ceramic tiles, roofing felt, soft roofing and other roofing materials. The illustration below shows the allowable slope angles for various types of roofing.
Basic structures of truss systems
First of all, it is worth considering the basic types of truss systems regarding the location of the walls of the house, which are used in all roof structures. The basic options are divided into layered, hanging, and also combined, that is, including elements of both the first and second types of systems in their design.
fasteners for rafters
Layered system
In buildings where internal load-bearing walls are provided, a layered truss system is often installed. It is much easier to install than a hanging one, since the internal load-bearing walls provide reliable support for its elements, and in addition, fewer materials will be required for this design.
For rafters in this system, the defining reference point is the ridge board, on which they are fixed. The non-thrust type of the layered system can be equipped in three versions:
- In the first version, the upper side of the rafters is fixed on a ridge support, called a sliding one, and their lower side is fixed by cutting to the Mauerlat. Additionally, the rafters in the lower part are fixed to the wall with wire or staples.
- In the second case, the rafters in the upper part are cut at a certain angle and interconnected using special metal plates.
The lower edge of the rafter legs is attached to the Mauerlat with movable fasteners.
- In the third version, the rafters are rigidly fastened in the upper part with bars or processed boards located horizontally, parallel to each other on both sides of the rafters connected at an angle, and a ridge run is pinched between them.
In the lower part, sliding fasteners are used to fix the rafters, just as in the previous case.
It is necessary to explain why sliding fasteners are often used to fix the rafters on the Mauerlat. The fact is that they are able to save the load-bearing walls from excessive stress, since the rafters are not rigidly fixed, and when the structure shrinks, they have the ability to move without deforming the overall structure of the roofing system.
This type of fastening is used only in layered systems, which also distinguishes them from the hanging version.
However, in some cases, a spacer system is used for layered rafters, in which the lower end of the rafters is rigidly fixed to the Mauerlat, and in order to remove the load from the walls, puffs and struts are built into the structure. This option is called complex, as it includes elements of a layered and hanging system.
The roof is one of the main elements of a residential building. Both the comfort inside the house and the service life of the building depend on how well its device will be made. The roof plays a particularly important role in multi-storey residential buildings, the total area of which exceeds several hundred square meters.
What is the roof of the house made of?
The roof of the house is the uppermost part of it, used to protect the load-bearing elements and the living space of the building from precipitation. In addition, it is a heat-insulating barrier that reduces the outflow of heat from residential premises and protects the structure of the building from overheating.
The roof not only protects the under-roof space from precipitation, but also helps to keep warm in living quarters.
Depending on the functional affiliation of the building and its design, the roof may have a different look. The design and type of the roof determines its ability to drain snow and rainwater from its surface. The space under the roof frame is often used as a residential or utility room.
Any roof has a typical design, which is determined by the technology and temperature conditions in the region where the building is being built. To better understand this topic, consider the structural elements of the roof in more detail.
Roof frame
The roof frame is a bearing and supporting element responsible for its strength characteristics. The quality of the frame directly affects the service life of not only the roof itself, but also the structure as a whole.
As a supporting structure for roofing in private houses, a rafter system is usually constructed from a wooden beam.
Depending on the design, the roof frame may look like this:
- truss system - the most common type of roof frame, most often used for the construction of roofs of utility and residential buildings from timber, brick and foam blocks. It is divided into hanging and layered structures. The former are used in buildings where only external walls are load-bearing, and the latter are used in houses with internal load-bearing partitions that can be used as additional supports;
- support system of steel beams - used for the construction of roofs over buildings for industrial use. Unlike wood, metal allows you to create longer, and most importantly, solid beams without length mates. This, in turn, significantly increases the load-bearing capacity of the roof structure. Metal is a non-combustible material, which makes the roof safer and more durable;
- flat concrete frame - is reinforced concrete slabs laid on top of load-bearing walls at a certain angle. It is most often used to create roofs over small public buildings and storage facilities.
For the implementation of any special project, different types of frames can be combined or used in a modified form. For example, Roof truss systems are often built from wood and metal at the same time, which in one place of the structure makes the roof more durable and reliable, and in the other it does not weigh down the load-bearing partitions, thereby reducing the overall load on the foundation. This option can be used when one part of the house is located on a sloping slope. Lightening the roof structure will avoid excessive load on the columnar or pile foundation, which are most often used in such cases.
Video: gable roof frame for metal tiles
roofing cake
A roofing pie is a technology for laying roofing, steam and heat insulation in a certain sequence. Proper sequential laying ensures that each technological layer will perform its strictly defined function.
For example, if the waterproofing material is laid incorrectly (under thermal insulation), then moisture will get on the insulation, which will inevitably cause damage and loss of the characteristics declared by the manufacturer.
All layers of the roofing pie must be laid in a strictly defined sequence so that each coating can perform its assigned functions.
A typical roofing cake consists of the following technological layers:
- roofing material - a facing coating that is responsible for the appearance of the front surface of the roof and protects the lathing and the underlying layers of the roofing pie from water, dirt and foreign objects;
- lathing - a supporting structure necessary for fixing roofing material. Depending on the type of finishing coating used, the crate can be solid or sparse;
- waterproofing is a mechanically strong waterproof material that protects the insulation from getting wet. For this purpose, bituminous roll coatings, anti-condensation membranes or liquid mastics can be used. The specific method of waterproofing is selected based on the type of roof and insulation;
- thermal insulation - basalt roll or slab insulation, polystyrene foam, polystyrene foam, etc. The thermal insulation material must have a low coefficient of thermal conductivity, which guarantees long-term maintenance of the required climatic regime in the house at any time of the year;
- vapor barrier - a multilayer membrane that protects the insulation and other elements of the roofing pie from the penetration of warm, moist air from the interior.
The sequence of laying the technological layers of the roofing cake is determined by the type of roof being mounted and the materials used for this. The most common option is when waterproofing is laid under the roofing, then there is a layer of heat-insulating material, and a vapor barrier membrane is mounted under it.
The main nodes of the roof
The junctions of the roof to the wall, if the building has a complex shape, as well as the places where the roofing pie and the outer front cover fit to the remote parapet are no less important than the roof structure itself.
The integrity and durability of the constructed structure depends on the quality of their execution, since the use of low-quality materials or non-compliance with the connection technology can cause moisture and precipitation to penetrate under the roofing.
Roof junctions
The place or junction of the roof to the wall is a connecting seam, which is processed using waterproofing and protective materials. The junctions are the most vulnerable point of any roof, since wet debris constantly accumulates at the junctions of its elements.
If the junction is poorly insulated, then moisture quickly gets under the protective material and roofing. Constant absorption of moisture into the insulation will necessarily lead to the loss of its technological qualities.
All places where the roof adjoins the structural elements of the building must be carefully treated with waterproofing materials to prevent moisture from entering the under-roof space.
In addition, the junctions are subject to temperature deformations due to freezing and thawing of water - this increases the risk of leaks. In order to avoid problems during the operation of the roof, the abutment insulation technology is thought out in advance. The calculation takes into account both the temperature regime in the region where the building is being built, and the average level of precipitation during the year.
Depending on the type of roofing, junction points are arranged in various ways:
- metal roofing - connections are made with a small gap necessary for ventilation of the roofing pie. As a protective element, a metal bar or apron made of galvanized steel is used. The apron is attached directly to the adjoining wall at a height of 200 mm. Before installing it, the strobe in the wall is treated with a frost-resistant sealant;
- various types of tiles - the junction of the wall and roofing is protected with corrugated aluminum tape. Due to the small thickness, the tape exactly repeats the profile of the roofing. To seal the seam, hot bituminous mastic is used, which is poured directly along the seam line;
- bituminous roll materials - the junction can be made using various technologies. The most common method is laying the coating with an overlap on a vertical surface. In this case, the material is pressed against a rail, which is pre-treated with a sealant. The size of the overlap, as a rule, is at least 20 cm.
Cornice knot
The cornice closes and protects the lower part of the roof, the roofing pie, the truss system and other elements from moisture. In fact, the finishing of the cornice assembly directly affects the service life of the Mauerlat and the roof truss system, since with poor-quality sheathing, moisture flowing down the roofing can enter the under-roof space.
To protect against moisture ingress into the under-roof space, special metal strips are installed on the eaves overhangs - droppers and ventilation tapes
For the device of the cornice unit of a pitched roof, the following sequence of laying protective materials is used:
- Roof covering.
- Counter-lattice.
- Roof decking.
- Waterproofing membrane.
- Dropper.
- Bracket for fastening the drain.
- Gutter.
- Cornice plank.
- Overhang air element.
- Tape for ventilation.
- Double-sided adhesive tape.
The dropper protects the frontal board from condensate flowing down the waterproofing film, and the cornice bar prevents moisture and atmospheric precipitation from entering the under-roof space. The overhang aeroelement serves to create a ventilation gap and protect against penetration of birds and large insects under the roof.
Gable node
A pediment is an end section of a roof, bounded by a roof slope and a cornice. It protects the roof from moisture, and also plays the role of a decorative element.
The pediment completes the roof, but is not a mandatory attribute, since in some types of structures the roof is limited only by the eaves.
Most often, gables are arranged on pitched roofs, when various types of tiles, profiled sheet or soft bituminous coatings will be used as roofing.
From the side of the pediment, the under-roof space is protected by a wind board, and then by a pediment strip laid on top of the waterproofing layer
The sequence of laying materials when constructing a gable assembly is as follows (from the outer edge to the under-roof space):
- gable plank laid on top of the roofing;
- waterproofing material;
- wind board;
- crate;
- rafter.
When fastening the gable strips, the technology described in the instructions for the roofing should be observed. Usually they are mounted from the bottom up from the eaves to the ridge. When using several strips, the overlap must be at least 10 cm.
Valley device
The endova is the inner corner of the roof, which is formed at the junction of two slopes. In fact, during the construction of multi-pitched roofs, the valley is a key structural unit, since atmospheric precipitation will flow down it. The roof valley always experiences increased loads, therefore its installation must be carried out especially carefully, in full accordance with the technological requirements established by the manufacturer of the roofing material used.
Devices of the valley node for a pitched roof are made using special additional elements that are mounted on a continuous crate
A typical version of the valley node for a metal roof is represented by the following elements:
- valley upper;
- sealing material;
- roofing;
- lower valley;
- solid crate;
- waterproofing membrane;
- roof truss system.
The valley is usually laid on a continuous crate, which is mounted on both sides of the junction of the slopes. When using metal coatings (corrugated board, metal tiles, seam roofing), the main protective element is the lower valley. It is laid under the roofing material and serves as a kind of gutter through which moisture flows into the drainage system. The upper valley in this case is more of a decorative element that covers the entire structural unit and protects it from birds and foreign objects.
ridge knot
The roof ridge is the upper horizontal edge formed by the conjugation of two slopes. The ridge strip or tile protects the rafter junction, thermal insulation and sheathing from moisture and is mounted last. Depending on the roofing, different ridge elements are used.
The device of the ridge knot is performed last, when the roofing is laid
For example, a ridge assembly for a soft roof looks like this (from top to bottom):
- ridge soft tiles;
- roofing;
- lining carpet;
- roof sheathing.
In some cases, a 40x40 or 50x50 mm ridge beam is nailed along the edge, on which the underlayment carpet is laid. If you plan to mount the roofing yourself, study the instructions for the material - it must contain a diagram of the arrangement of all the main roof nodes.
Parapets along the perimeter of the roof
A roof parapet is a protective structure that is mounted along its perimeter. Usually parapets are mounted on flat roofs, but quite often they can be seen on pitched roofs, especially in the residential multi-apartment sector. The main purpose of the parapet is to ensure the safety of the person on the roof. Sometimes such designs are used as a decorative element.
The installation of parapets (SNiP II-26–76) is mandatory for buildings whose height to the roof eaves is more than 10 m, and the slope angle does not exceed 12 degrees. On steeper roofs, the installation of fences is carried out already at a height of 7 m.
If we consider low-rise private housing, then the installation of parapets is relevant only for houses with a flat roof. For gable or hip roofs, the installation of parapets is optional. But it should be borne in mind that if annual roofing maintenance is planned on pitched roofs, then security measures must be appropriate.
In private construction, parapets must be arranged only on flat roofs.
For the manufacture of parapets, the following materials are used:
- reinforced concrete blocks;
- brick and foam blocks;
- galvanized metal.
According to SNiP, the height of the parapets must be at least 45 cm. The optimal height is selected based on the architectural features of the building and the personal preferences of the owner of the house.
The junction of the roofing cake to the parapet is carried out using hydro- and heat-insulating materials. At the junction of the parapet and the roof, a transitional ledge of mineralized insulation is laid. To fix the insulation, a special cold mastic is used. Waterproofing is mounted with an overlap of 20–25 cm on a vertical surface.
To protect the parapet, a similar waterproofing material is used, which is fixed with an overlap on the previously laid canvas coming from the roof side. A U-shaped galvanized steel box is also installed on top of the insulation.
Additional elements of the roof
Additional elements of the roof are products designed to connect various components and parts of the roofing. In addition, they provide additional functionality, as well as improve the appearance of the front surface of the roof and the roof as a whole.
Various additional elements allow you to protect the roof structure from weather influences, preventing the penetration of moisture, dust and debris into the under-roof space. It should be understood that depending on the design of the roof, the number and need for the use of additional elements may vary.
For a metal roof, a wide range of additional elements are used to protect its structural units from the penetration of moisture and debris and give the entire building a finished look.
For example, typical additional elements used in the construction of a pitched roof include:
- skate and valleys;
- adjoining elements;
- strips for cornices;
- end strips;
- corner strips;
- snow barriers;
- adapters;
- gutters.
Before choosing additional elements, you should carefully study the roof project and, based on it, calculate the amount of material needed. It is not recommended to save on additional elements, since the safety of the roof structure and the roofing cake at the junction, on the ridge and drains depends on their quality.
Video: roof device - insulation, ventilation, board selection
The device of various types of roofing
The device of the roof and the roofing cake varies greatly depending on the type of construction. This is due both to the design features of the roof being built, and to the characteristics of the materials used for its construction. For a more detailed description, consider the most common types of roofing in more detail.
Warm and cold roof
A warm roof is a generalized concept denoting an insulated roof structure. That is, any type of roof can be warm or cold, depending on whether the appropriate hydro- and heat-insulating materials were used during their installation.
If, during the construction of the roof, the standard roofing pie is completely mounted, then it is called warm
If we talk about the private sector, then in buildings that will be used for year-round use, insulation is recommended for any type of roof. The most common roof structure for private houses is a gable structure, so we will consider the construction of a roofing pie using its example. The main elements of a roofing pie of a warm roof are:
The number of layers of insulation is selected individually for each project at home. This takes into account both the dimensions of the building itself and the possibility of creating a residential attic space, as well as the temperature regime in the region where construction work is being carried out.
Sometimes, if the owner of the house, for example, decided to save on roof construction or the attic space will not be used as a living space, the roofing can be done without laying thermal insulation material and vapor barrier. Such a roof is called cold. The role of the vapor permeable material will be played by a moisture-resistant vapor barrier membrane. Cold roofs are usually arranged in seasonal houses and outbuildings.
Pitched roof with metal coating
A metal roof is usually a pitched structure with a wooden truss system. The type of rafter system is selected based on the location of the load-bearing walls of the building. The use of metal as a roofing material has an impact on the technology of constructing a roofing pie for such a roof.
The most popular roofing material for private residential buildings is metal.
The following materials are used for the installation of a metal pitched roof:
- additional elements - a metal ridge, side wind strips, gutter and gutter strip, gutter and other elements installed after the installation of the metal coating;
- roofing - flat sheet material (folded roof), profiled sheet, metal tile or other painted metal materials;
- crate - edged boards or metal profile elements, fixed in increments of 25–30 cm;
- truss system - can be made of both thick edged boards or timber, and metal. In private construction, the first option is most popular due to its accessibility, ease of installation and lighter weight.
The remaining technological layers of the metal roofing cake are identical to the option described in the section above. It should be noted that the metal coating is particularly prone to the formation of condensation on the inner surface, where, despite the presence of special protection, humid air from the house still penetrates. Therefore, the arrangement of all ventilation gaps provided for by the technology when using a metal roof is strictly necessary.
Waterproofing is made of a moisture-resistant membrane, which is fixed on the roof truss system, and any slab insulation with a thickness of 5 cm or more is used as thermal insulation.
Video: organization of waterproofing for a metal roof
pyramid roof
A pyramidal or hipped roof is a pitched structure, where each of the four slopes is equal in area, and there is a square at the base of the roof. In fact, each of the four slopes is an isosceles triangle.
In some cases, a pyramidal roof is understood as a structure with any number of slopes - the main thing is that they be the same size. Such roofs look very harmonious and are not similar to other types of roofs.
According to its design, the pyramidal roof is made according to the traditional scheme with truss elements, although it has some features compared to the classic gable version.
The truss system of the pyramidal roof has a number of structural differences from the device of a standard gable roof.
The truss system of the pyramidal roof consists of the following elements:
- rafters - diagonal beams located at the corners of the structure. They are made of timber or double thick boards;
- mauerlat - the lower horizontal bar necessary for supporting and fixing the diagonal rafters;
- rafter legs (spiders) - support bars attached to diagonal rafters. Provide increased strength and rigidity of the structure;
- struts - vertical racks used as supports for rafter legs;
- crossbars - horizontal beams that are mounted at the top of the diagonal rafters. Increase the strength and wind resistance of the roof;
- beds - horizontal elements at the base of the structure, to which racks are attached.
The general arrangement of the roofing pie of the pyramidal roof is not much different from the classic version.
- The rafter system is filed with a draft board.
- The vapor barrier membrane is laid out and fixed.
- A heater of the required thickness is laid on it.
Insulation plates must be laid so that they go into the space between the rafters with a noticeable tightness and do not leave gaps for the penetration of cold air
- Waterproofing material is laid.
- A counter-lattice is mounted, additionally fixing the waterproofing layer.
The bars of the counter-lattice, laid along the rafters, fix the waterproofing film and form the necessary ventilation gap, and the boards of the longitudinal lathing serve to fasten the roofing
- The longitudinal crate is laid.
- Roofing is installed.
The hipped roof looks very harmonious and gives the house the look of a fabulous tower.
Roof made of SIP panels
SIP-panel (from the English Structural Insulated Panel) is a building material in the form of a plate, consisting of two outer plates of solid material, between which there is a layer of insulation. On the one hand, the shell of the SIP panel is made of OSB-plate, on the other - from a sheet of corrugated board or also from OSB-plate. Panels with a metal coating are used as an independent roofing, OSB products are used as a continuous flooring under a soft roof.
As a rule, foam or expanded polystyrene of a certain density is used as a heat insulator. Sometimes polyurethane foam is pumped into the space between the plates or polypropylene is mounted. Previously, the panels were used only as a material for the construction of the frame of buildings, but now they are also successfully used for the construction of roofs.
Unlike traditional materials, there is no need to create a massive frame for the installation of SIP panels.
A typical device for a gable roof made of SIP panels for a soft roof is the following sequence of elements:
- strapping - made of wooden beams with a comb. The size of the beam depends on the size of the panel groove;
- ridge and end rafters - a bar of the same size is used for manufacturing. For a skate, you can take a board with a thickness of 5 cm or more;
- mauerlat - made of timber from 100x100 to 200x200, depending on the size of the house and the thickness of the walls. It is mounted on the upper ends of the walls to provide support for attaching the strapping.
Each SIP panel is laid on the rafters and the nearest horizontal runs. Then it is adjusted and processed with a special adhesive mass or frost-resistant mounting foam. Upon completion, a strapping of a suitable size is mounted in the groove of the panel. In this case, the harness is also fixed to the Mauerlat and the ridge.
Video: installation of a roof from SIP panels
semi-circular roof
The semicircular roof is a "bent" structure with smooth vault lines. For its construction, a truss system based on arcuate lamellas is used.
For their manufacture, a board of the highest or first grade is used, which is steamed up to 100 degrees. Due to the absorption of a large amount of moisture, the wood becomes elastic. For bending workpieces, special forms are used. After shaping, the blanks are glued together and sent for drying.
As a result, the customer acquires a certain set of material sufficient for the manufacture of a roof according to a pre-compiled project. The assembly scheme is as close as possible to the technology that can be found when installing domed metal roofs.
For the construction of a semicircular roof, special truss elements are used, made for a specific project.
The semicircular roof consists of the following elements:
- mauerlat - the lower support beams necessary for fixing the elements of the truss system;
- lamellae - elements of small length, having an arcuate shape. They are assembled into a frame with the help of stringers;
- stringers - horizontal elements that are attached between the lamellas when assembling the frame;
- partitions - horizontal beams fixed from the end of the roof. Provide rigidity and strength of the structure.
To assemble the truss system of a semicircular roof, galvanized fastening strips and self-tapping screws are used. The size of the fasteners is selected for the specific size of the lamellae. The sequence of laying insulation and insulation is completely identical to that described above.
The device of expansion joints
The expansion joint, located on the surface of the roofing, is designed to compensate for the thermal expansion of the facing material. In addition, it reduces the resulting stresses due to movement or shrinkage of the roof structure.
The layout of the expansion joints depends on the size and design of the building. In the case of residential buildings, the arrangement of the seam is necessary when the roof of one building adjoins the wall of another, when materials with different degrees of linear expansion adjoin, and also in places where there is a sharp temperature drop inside the room.
A vapor barrier, mineral insulation and a bituminous roll coating are used for the construction of an expansion joint on a flat roof.
In private construction, expansion joints are arranged on flat soft or pitched roofs covered with bituminous roll coatings. They are made up of several components:
- vapor barrier - is laid without joints under the expansion joint. It is better to use a moisture-resistant vapor barrier membrane;
- space at the point of rupture - in the place where the expansion joint passes, a compressible non-combustible heat-insulating material is laid. Compressibility is determined according to GOST 17177;
- temperature seam - a mineral heat-insulating material is laid over the gap so that it overlaps the seam by 15 cm on each side. Hot mastic is used for fixing;
- heat insulator over the seam - for additional stress compensation, a mineral insulation is laid over the seam, rolled into a tube Ø50–70 mm.
Laying roofing to protect the expansion joint is carried out with small canvases overlapping the joint by 30–50 cm on each side. More detailed technology for the installation of expansion joints should be clarified with the manufacturers of the roofing material that is planned for purchase.
Roof access device
During operation, the roof and additional elements of the roof need periodic inspection, which allows you to prevent emerging or eliminate problems that have already arisen. To do this, it is desirable to equip the roof with a special exit.
The type of device used depends not only on the size of the roof slope, but also on the size of the attic space. Some types of structures are simply inconvenient to keep in a small space.
Transparent hatches for access to the roof are also excellent sources of natural light
To access the roof, the following methods are used:
- roof hatches - ready-made products that are mounted in pre-prepared holes in the roofing pie. They are a steel or plastic box with a fixed monolithic or transparent hatch. Exit to the roof is carried out by means of a ladder or ladder;
- hatches with a folding ladder - devices combined with an attic ladder, which folds into a specially designated space. As a rule, in the folded version, this type of hatches is no different from the previous one;
- a roof window is a compromise option when the window is used not only to illuminate the under-roof space, but also to exit to the roof. It is highly desirable that roof drains be provided on the roof surface;
- outdoor staircase - a metal welded or wooden staircase, which is attached to the wall of the house as needed. If desired, it can be fixed on the surface of the wall, but not all owners of private houses will like it.
Installation of roof hatches is not particularly difficult and is carried out according to the instructions attached to them. Usually it is a steel box, which is fixed to the truss system with self-tapping screws. In some cases, the box is mounted directly on the mounting foam.
Roofing is a vast topic that requires careful study of the technology. Especially when it comes to multi-pitched roofs, which have a large number of junctions of slopes. If you decide to do the installation of the roof with your own hands, carefully study all the available information and only then proceed with the work.
December 12, 2017Specialization: facade finishing, interior finishing, construction of dachas, garages. The experience of an amateur gardener and horticulturist. He also has experience repairing cars and motorcycles. Hobbies: playing the guitar and much more, for which there is not enough time :)
Any roof is subjected to various loads every day, as it is affected by wind, precipitation, and it also holds the roofing. In order for the roof to cope with all these loads for many decades, it must be properly designed. Therefore, for everyone who wants to do construction on their own, I recommend to figure out what parts and nodes of the truss system exist, and what function they perform.
Frame elements
All details of truss systems can be conditionally divided into two types:
- Basic. These parts form the roof frame, called the truss system. Not a single roof can do without them;
- Additional. This group includes elements that may be present in some types of roofs, while others do without them. The task of additional elements is to increase the rigidity and strength of the frame.
Main knots
So, the following elements belong to the main nodes and details of the truss system:
- Mauerlat. This, one might say, is the basis of all roofing systems, since rafter legs rest on the Mauerlat. Its design is extremely simple, in fact, it is an ordinary bar (a log in log houses), laid along the perimeter of the walls. Its task is to evenly distribute the load from the roof to the walls of the building.
I must say that at a gable roof, the Mauerlat can be located not along the perimeter, but only on the side walls, since there are pediments on the end walls, which are a continuation of the wall;
- Rafter legs (hereinafter CH), or simply rafters. These parts are the supporting element that forms the slope and its angle of inclination. They take on the wind and snow load, as well as the weight of the roofing material, and transfer it to the walls through the Mauerlat and other elements.
Rafters are lateral (main), diagonal (installed at the junction of hip roof slopes) and shortened (diagonal rafters rely on Mauerlat);
- Rafter farms. They are formed by paired (reciprocal) rafter legs. It must be said that truss trusses are present on all pitched roofs except for shed roofs, since they do not have reciprocal rafters;
- Skate knot. It is the top of the roof truss, i.e. formed by the junction of two CHs. The ridge knot, like the trusses themselves, is absent only from shed roofs.
That's all the main knots of wooden roof structures that form them.
Additional
Additional details include:
- Run. This is a horizontal beam that connects all CHs within one slope;
- Skate run. It is the same horizontal beam as a regular run, but which runs in a ridge knot, i.e. connects two legs of each truss at the same time.
I must say that the ridge run can be installed in several ways - above the junction of the rafters, in the center of the junction, i.e. legs rest on the run, or under the rafters;
- Puff (bolt, fight). It is a beam that connects two reciprocal legs, preventing them from moving apart. We can say that the tightening removes the spacer load from the bearing walls;
- Supports. Can support rafters, all types of runs or puffs. Supports transfer the load to the internal walls of the building, columns or ceilings;
- Struts (rafter legs). They are inclined supports, which have the same function as the vertical racks. The only thing is that they support only the legs, i.e. are one of the elements of wooden trusses. Rafter legs transfer the load to the load-bearing elements of the building, or to the ceiling;
- Filly. These elements form the overhang of the slope in the event that the CHs do not go beyond the walls. In fact, they lengthen CH, i.e. are their continuation.
That's all the elements that make up the frames of pitched roofs.
A few words about the types of systems
So, we figured out the nodes, now let's look at the main types of truss structures. There are several of them:
- Shed. As I said, these structures do not have trusses. The angle of the slope is formed due to the different heights of the walls on which the CHs are laid, or due to the run, which is laid on racks installed on one of the walls;
- Gablesloping. Rafters are called rafters, which are supported by racks or struts that transfer the load to the internal load-bearing elements of the building. The frame of such structures is formed only by trusses, i.e. they do not have diagonal legs.
- gable hanging. Hanging rafters differ from layered rafters in that they transfer the entire load from the roof only to the outer walls;
- Hip. Unlike gables, at the ends instead of vertical gables they have inclined hips, i.e. end slopes. As I said, the hips form diagonal and short legs;
- broken lines. They are a gable structure, each CH of which is divided into two parts and is located at a different angle. Skating, i.e. the upper legs form a gentle slope, and the lower legs are steep. This design allows you to increase the attic space, as a result of which it can be used as an additional floor.
Typical broken (mansard) systems have racks on which the upper and lower CHs rest. The reciprocal racks are interconnected by puffs (attic floor beams).
There are also semi-mansard structures, which, in fact, are the usual hanging gable roof systems. The only thing is that their fastening with a Mauerlat is usually made sliding (movable), which allows you to increase the CH deflection, and thereby reduce the spacer load on the walls.
Despite the fact that the designs of all the above systems are different, they consist of the same parts that we have already familiarized ourselves with.
One last thing about fasteners
Finally, I propose to consider how the connections of the main nodes are made, such as:
- Rafter / Mauerlat;
- Skate knot.
The rest of the details do not deserve special attention, since their docking most often occurs by washing down the interface (to increase the area of \u200b\u200bfitting the parts) and lining the steel plastic / corners, which are fixed with screws. Sometimes fasteners are not even used, i.e. parts are fastened to each other with screws without any overlays.
Connection of rafters and Mauerlat
The leg and Mauerlat mount can be made in several ways:
- With grooves. In this case, grooves are cut out under the Mauerlat, into which CH is inserted. Then it is additionally attached to the Mauerlat on both sides with a steel corner;
- Tooth and thorn. This method is usually used to attach the CH to the puff. Its principle is based on the fact that a spike is selected at the end of the sawed CH, and a groove is selected in the puff. In addition, the leg itself rests against the so-called tooth, i.e. protrusion in the puff, which takes on the expansion load.
It must be said that in recent times, fasteners such as a tooth with a spike are rarely used, since it is much easier to use special fasteners, the same corners and plates;
- By washing down. In this case, the CH is sawn so that a right angle is formed at the junction with the Mauerlat, as a result of which the rafter not only rests on the beam, but also rests against its side surface, thus transferring the spacer load. I must say that instead of washing down, you can fix the bar, as shown in the diagram below.
Connection of rafters and ridge run
The connection of CH and run can be done as follows:
- With a groove. In CH, two reciprocal cuts are made, as a result of which, after the junction of the rafters, a groove is formed for the ridge run;
- Hard pinching. The principle is based on the fact that puffs are installed under the run and above it;
- Got drunk on the way. This is the simplest and most common method, the principle of which is based on sawing CH for maximum fit to the beam. In this case, fixation is carried out with a steel corner.
Here, perhaps, are all the main nuances of assembling truss systems.
Conclusion
We have found out what parts the truss systems consist of, what types they are and how their main elements are connected. If I missed some points or something is not clear to you - write comments, and I will be happy to answer your questions.
December 12, 2017If you want to express gratitude, add a clarification or objection, ask the author something - add a comment or say thanks!
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