Recently, there has been a return to the use of various architectural elements that were undeservedly forgotten in the era of industrial construction. Again you can find bay windows, mezzanines, attics, which make the exterior of the house more interesting, and at a relatively low cost allow you to increase the interior space. For example, an 8x10 mansard roof truss system will increase costs by about $ 4,500, while allowing you to add 60-65 m 2 of usable area to the area of \u200b\u200bthe house.
Types of mansard roof truss systems
In practice, several types of truss systems for the attic are used. They are classified according to the type and shape of the roof: two-, three- and four-pitched, hip and half-hip, broken. The simplest option is double truss system attic. Its advantage is a simple and reliable design that can withstand heavy loads. At the same time, there are also disadvantages - a simple form does not allow you to create an interesting design, which, however, is compensated by the addition of decorative elements. Another disadvantage is more significant - the limited internal space, which is significantly less than in the case of a sloping roof.
Idea You can get rid of the lack of space by building a semi-attic - that is, a room with side walls 1.5-1.8 meters high. This will increase the internal volume while maintaining the advantages of a gable roof design.The drawing shows an example of a mansard roof device in the form of a half-attic with walls 1.8 m high
The most interesting from an architectural point of view is the rafter system of a broken mansard roof. It allows you to show imagination, of course, subject to compliance with building codes and, above all, strength characteristics. Such a design can have a regular and asymmetric shape. The configuration is selected based on the features of the house and the layout of the interior space of the attic. In some cases, the mansard roof truss system allows you to create quite an interesting interior space, especially if it is possible to plan a second light or mezzanine. It is important to use the volume as fully and efficiently as possible - this is not an easy, but very interesting task, which allows, at a relatively low cost, to increase the usable area and make the house more comfortable.
Advice Since space is limited at the junction of the attic floor to the roof, it is advisable to organize storage places, install furniture, and lay engineering communications.
Places near the walls of the attic are best used to install convenient cabinets, shelves and built-in furniture.
Elements and nodes of rafter systems of the mansard roof
The rafter system is the basis of the roof, its skeleton, on which the roofing pie and the inner lining of the attic are mounted. Often it is used as a basis for laying engineering systems and communications. In turn, the truss system of the mansard roof consists of component units and elements, the combination and mutual arrangement of which ensures the transfer of wind and snow loads from the roof to the load-bearing walls of the building:
- rafters (hanging and layered);
- Mauerlat;
- runs (ridge and side);
- connecting elements (braces, struts, diagonal ties).
The loads acting on the roof structures of mansard roofs are quite large and reach an average of 200 kg / m 2. However, in each case, this is determined based on the design features of the roof, as well as the wind and snow loads available in the area. In any case, the rafters must be guaranteed to withstand these loads and have the necessary margin of safety to withstand very strong winds or heavy snowfall.
When calculating the load on the truss system, it is very important to take into account the likely amount of precipitation and wind strength.
The parameters and main components of the mansard roof truss system are determined by calculations. Calculations make it possible to determine the length, profile and cross section of each structural element and the features of the pairing of parts with each other. The strength of the entire structure largely depends on the strength of the connection of the nodes of the truss system of the mansard roof. The most common types of joints are grooved, screwed, bolted and welded. The choice of type of connection depends on the design loads, the material used and the design features.
Calculation and drawing of the mansard roof truss system
Having chosen the type, and having determined, it is necessary to calculate the truss system of the mansard roof. At the same time, it should be borne in mind that the rafters not only provide strength and reliability of the roof, but also shape the interior space of the attic. It is assumed that part of the area will have a small ceiling height. There, as a rule, furniture is located, or used to organize storage places. Despite some restrictions, the interior space should be spacious enough and not cause discomfort.
The first design stage is the choice of a mansard roof truss system scheme. The scheme determines the type and location of the elements of the truss system. In particular, the type of rafters is determined: layered or hanging. The difference between these elements is as follows: the rafters on the attic floor are supported by side walls or other supports. Hanging rafters form a single, rigidly interconnected structure. Depending on the width of the span, the scheme of the mansard roof truss system can be reinforced with additional connections.
The diagram shows the main elements and parts of the mansard roof truss system and their relative position
Next, you need to perform calculations that take into account the wind and snow loads that will act on the roof. The material, cross-section and distance between the rafters of the mansard roof depend on these parameters. It is recommended to apply the so-called "margin of safety". This means that the result obtained must be multiplied by a multiplying factor, thereby guaranteeing increased reliability of the attic truss system. Taking into account the features of operation, the value of this coefficient is taken from 1.5 to 3.
Important When making calculations, it is necessary to take into account the weight of the roofing system. In particular, when using ceramic tiles, the cross section of the beam for rafters must be at least 70x150 mm, with a step of 0.5 m.Quite often, the mansard roof truss system is created from wooden structures. It is recommended to choose wood that has high strength and at the same time is minimally susceptible to decay. Larch can be considered the best option, however, it is also possible to use cheaper wood with sufficient strength. In this case, more thorough treatment with antiseptic formulations is necessary. It is desirable that these compositions also have flame retardant components.
The rafters of the mansard roof must be treated with a special antiseptic that prevents wood from rotting
However, it is not always possible to use wood for the manufacture of rafters. For heavy loads, it is necessary to use a beam with a large cross-sectional profile, or a significant reduction in the distance between the elements. This leads to a significant weighting of the entire structure of the mansard roof and, as a result, to the need to increase the bearing capacity of the attic walls. In this case, metal roof rafters are often used.
The results of the calculations are reflected in the drawings, which indicate all the design decisions made for this attic truss system. If the work is done independently, then it is allowed to develop a simplified sketch of the mansard roof truss system instead of a detailed drawing. In this case, the sketch must have all the information and parameters necessary for the assembly and installation of rafters.
An example of a schematic drawing of an attic rafter system indicating the main parameters and distances
The device of the attic truss system on the example of a gable roof
The device of the mansard roof truss system depends on the type of roof chosen for the house project. The most simple, and at the same time reliable and effective can be considered a classic gable roof. Of course, it looks simple compared to complex, broken roofs, but at the same time contains many of the basic elements and parts that are characteristic of all types of mansard roof truss systems.
The rafter system of a gable mansard roof consists of several main parts and elements. In general, this is:
- Linear parts and elements - beams, columns, rod systems;
- Planar parts and elements - plates, panels, floorings;
- Spatial parts and elements - shells, vaults, three-dimensional elements.
In practice, not all parts and elements of the mansard roof truss system are used. In particular, for a gable roof, rafter legs, crossbars, ties, struts and struts are used. Their dimensions and relative position are determined during the design. Together, all these elements form a truss roof truss system.
Six examples of a truss truss, indicating the height of the ridge and the location of the rafters
The truss is the most important part of the mansard roof truss system. The number of trusses depends on the length of the facade and the chosen installation step. The type of truss and the installation step are interrelated values, the more complex and stronger the spatial structure of the element, the greater the step can be used during installation. In turn, an important element of the farm are the rafters for the attic, or, as they are also called, rafter legs.
Rafter legs are the most important element of the truss, the stability of the roof depends on the distance between them.
The video attached to the article talks in sufficient detail about the rafter system of the mansard roof. From it you will learn about all the intricacies of the truss system and installation work. Variants of roofing systems are considered from a simple gable to a more complex - a broken line. Following the instructions and recommendations available in the video instructions, even a novice master is able to understand the features of this work and perform it on his own.
Installation of the attic roof truss system
Work on the installation of mansard roof rafters is also called rafters. This is a set of works on the marking and installation of rafters. At the same time, work is also being carried out to remove the horizontal of the ridge and trim the gable. You can do the rafters with your own hands. A good guide for this can be a video instruction below.
The installation of the mansard roof truss system has many features, many of which are unknown to novice craftsmen. The installation of the frame must be carried out on a hydro- and heat-insulating material. This increases the service life and reduces heat loss. Another common mistake is covering the elements with protective compounds after they are installed. Antiseptic treatment must be performed before installation, then the entire surface will be treated, and the rafters will last longer.
Note to the master Timber for rafter work must be pre-dried, its optimum moisture content is approximately 18%.The quality of fastening the roof truss system of the mansard roof must be given special attention. You can do it right, purchase high-quality materials and professional tools, but if the connection of the parts of the truss system is poor quality, then after a while a major overhaul will be required. The choice of fasteners is a separate section of the project, which determines the length and diameter of hardware.
To assemble the rafters of the mansard roof, it is necessary to use galvanized fasteners of the desired size. An attempt to save on fasteners does not give a significant result, but it contributes to serious problems during operation. The distance between the fasteners is selected in proportion to their size. The fastener pitch should not be very small so as not to reduce the strength characteristics of the part itself.
Installation of a truss structure of a gable mansard roof of a wooden country house
The first truss is mounted from one of the ends, while checking the correct installation vertically and horizontally. Then, from the other end, a second truss is mounted, and its verticality and horizontality are also verified. Between the trusses, two construction cords are pulled in parallel, which will be a guide for installing the intermediate rafters of the mansard roof.
Advice For temporary fixation of trusses, you can use struts made from substandard lumber or scraps.After all the trusses are installed in their places, they begin to install the side and ridge runs. Having assembled the truss system of the mansard roof, you can move on to other types of work: filling and sheathing the gables, installing a roofing pie, heat and sound insulation, interior cladding and decoration.
Many male people, finding a family, sooner or later think about purchasing their own home. Someone takes an apartment on a mortgage, and someone saves money for. But not many people manage to save up for a big house, and the alternative would be to build a house with.
What is a mansard roof
The attic can be built from or from a suitable material for you.
It will not be difficult to build an attic, but patience, diligence, suitable materials and the availability of a tool are necessary.
The shape and design of the roof must be included in the design of the house in order to avoid incidents during further operation.
You can take a typical project for building a house or order it from professionals. In such documentation, you will be able to understand where to start and choose the right materials for construction.
Now you can buy everything you need, but first equip a place to store building materials and tools. The storage area must be dry and free from rain or snow to damage the building material.
Also, under a canopy, it will be possible to equip a small workshop for the manufacture of some parts of the house or roof. For a house from or who does not have the opportunity to build a full-fledged second floor, choosing a mansard roof would be the best option. House from will be a budget option. Next, we will consider the attic device.
Structural elements of the attic in design are practically no different from gable roofs.
Materials required for the construction of a mansard roof
The roof is the outer covering of the roof, it protects the inside of the attic and can be made of various materials.
For roofing, as a rule, such materials are used:
Stages of building a mansard roof with your own hands
After getting acquainted with the names of the roof device, we can continue to further disassemble the construction in stages.
First stage
The construction of the attic always begins with Mauerlat mounting.
When building on a stone box, you need to think about fixing with studs or anchors at a distance of no more than two meters.
At the locations of the anchors, the timber is marked, a hole is made in it and put on the anchor, then the Mauerlat is fixed with nuts to the wall.
To simplify the marking, it is necessary to put the beam on the anchor and lightly walk with a hammer on top, after these manipulations there should be traces, they will be places for drilling holes.
Second phase
The second stage in the construction of the attic will be the installation of floor beams.
Actions must be consistent.
First of all, the extreme beams from the ends are installed, then the intermediate ones. Between the intermediate and extreme beams, it is necessary to pull a nylon cord or scaffolding, or you can still use a level. These devices are needed to indicate the plane.
Third stage
We install, align in a vertical position and fix the support posts.
We strengthen with jibs and make horizontal runs.
It should be borne in mind that the racks are placed in equal numbers with the floor beams on two parallel sides of the attic.
The rigidity of the supporting structure is provided by horizontal runs.
Fourth stage (truss system)
The details of the truss structure prepared according to the template are installed according to and fixed to the vertical supports.
Elements can be fixed using boards or metal plates with holes.
Fifth stage (pediments and crate)
Z 
we sew the gables, leaving room for, we attach the sheathing boards all over the roof. This is the easiest work in the construction of the attic.
Sixth stage
So we have almost come to the end of construction and this is the insulation of the mansard roof with our own hands.
In modern construction, a variety of materials are used for insulation and you can purchase them at any hardware store.
final stage
Mansard roof truss system
More and more architectural, original houses appear, decorated with bay windows, superstructures, mezzanines. Attics are coming into fashion, expanding the useful area of \u200b\u200bthe house. But mansard roofs, unlike a simple gable roof, require complex truss systems. Correctly calculating them and installing them is not at all easy. Below we will try to briefly highlight this issue and provide useful recommendations from experts.
Varieties of truss systems
At the design stage of the house, the roof structure should be calculated. Calculations using complex formulas should give the value of the load per meter of a square truss system. For residential buildings, the normative load is 50 kg / m2.
In accordance with the calculations, the type of roof structure of the attic is selected. The main varieties include:
- hanging rafter system;
- sloping roof rafter system;
- layered gable roof system;
- combined.
The most common are the combined rafter systems of pitched roofs. It is recommended to entrust the calculation of complex truss systems to professional designers.
Advice!
To increase the useful area of the building, you should choose the design of a multi-pitched mansard roof.
roof truss elements
Experienced specialists will perfectly understand what the article is about, because they know all the terms and names of structures. In order to make it clear to everyone, here are the common names of the mansard roof structural elements:
- Mauerlat - a beam fastened along the upper crown or along the wall of the house, on which the rafter system rests;
- Floor beams - a wooden structure that plays the role of an attic floor and, at the same time, the ceiling of the underlying room;
- Racks - vertically mounted pillars on which rafters and beams are attached.
- Runs - beams (boards) located horizontally, serve as a support for the rafters;
- Rigel - horizontal beams in a U-shaped truss. They serve as a support and pull together the pitched rafters, have another name "puffs";
- Rafters - timber or boards that form the basis of the roof structure;
- Suspension - a rack, the task of which is to support the crossbar, facilitating its work, is also installed horizontally;
- Lathing - a plank or plywood base on which roofing material is laid;
- Filly - a board that serves as the basis for mounting the overhang, is installed at the bottom of the truss system.
Elements of the truss system Rafter system calculations
The choice of truss structure largely depends on the size of the building, in accordance with which the span length is determined, i.e. distance between main posts. For small houses, preference can be given to a gable design.
Gable roof truss system with attic Structural calculations are carried out in order to determine the load, in accordance with the standards and building regulations. The main rule for a mansard roof is to limit its height, which should not be less than 2.5 meters indoors. Thus, the roof must be at least 2.80 m high, since it requires the laying of an insulating layer, and finishing inside the attic itself.
Gable roof structure Be sure to make a design drawing, on which you should put down all the dimensions and display the elements of the frame as much as possible. The drawing should show the dimensions of the house, the angle of the rafters, the height of the roof.
Advice!
In order to make accurate calculations for all loads on the roof and its elements, it is recommended to use the calculator posted on many sites dedicated to the construction of roofs.
It is enough to enter the type of roofing, the material of the mansard roof frame and dimensions. The program will calculate the cross-sectional angles and rafter spacing, give recommendations on the design of the crate.
Calculation of the truss system
Attic roof installation technology
You should start with the installation of a Mauerlat, which is laid along the perimeter of the upper edge of the walls, if the house is brick or block. In houses made of timber or chopped with Mauerlat, the upper crown can serve. The beam from which the Mauerlat is made must have a cross section of 100x100 mm or 150x150. Softwood for timber should be well dried. Mauerlat beams are fixed with anchors or studs to the walls in increments of about two meters. Under the Mauerlat, waterproofing is installed, as a rule, of a roll type (roofing material).
Next, proceed to the installation of the ceiling. Beams 150x200 mm, laid on the Mauerlat, should protrude from the walls of the house by about 0.3-0.5 m. The beams are fixed with corners and screws (wood screws), starting from the extreme ones, then intermediate ones.
Important!
When laying, use a cord to control the horizontal level so that the beams lie in the same plane.
The distance between them, as a rule, is 0.5-1.0 meters, if it is planned to lay insulation, the standard sheet width of which is 0.6 m, then it will be more convenient to withstand the same step of the beams.
Roof truss installation
Installation of support posts and girders
The next step is the installation of racks. For them, a bar 100x150 mm is used, the fastening of which is carried out on the front floor beams. It is necessary, using a plumb line, to align the verticality of each support and fix it with jibs. Intermediate supports are also installed on the beams strictly vertically, forming two parallel rows.
Intermediate supports of the roof truss system This is followed by the installation of runs, which can be made from a board 100-150 mm wide and 40-50 mm thick. Fixing the runs is done with nails and corners on the screws. Then, on top of the runs, plank crossbars are laid, for rigidity, mounted on the end.
The purlin beam forms a cantilever for supporting the diagonal roof rafters Advice!
As a result, the contour of the future attic space is formed. To give additional strength, the supports should be strengthened with struts and contractions.
Roof truss system Installation of truss elements
Installation of rafters, starts from the bottom. For them, a board 40-50 mm thick and 150 mm wide is suitable. With one end we rest on the Mauerlat close to the floor beams, and the other is attached to the girders with the help of corners, screws and nails. To install the rafters in the upper part of the roof, mark the center line of the roof. All rafters must be the same length. To do this, make a template board by making cuts on it from both ends. After that, according to the template, you can saw off the rest of the rafters.
rafter legs The rafters are mounted on girders, fixed in the upper part with metal plates. On the runs, the beams are fixed with cuts point-blank and fixed with corners on self-tapping screws.
Rafter system fastening For strength, the lower rafters should be reinforced with struts (board 50 × 150 mm). After fixing the struts, temporary stops can be removed.
Often the elements are connected not only with carpentry knots, but also with the help of fasteners. Rafter installation
In cases where floor beams are laid in wall pockets, fillets should be fixed on the lower rafters for the roof overhang. If the floors lie on the Mauerlat, then fillies are not needed, since the beams should protrude beyond the walls forming an overhang.
Sheathing is an important part of the roof structure. The crate is installed depending on the intended coverage of the mansard roof. Either the crate will be solid, or with gaps. A waterproofing layer should be laid on top of the crate, after which you can start sewing gables and laying roofing material - metal tiles, corrugated board or slate.
Roof deck under metal tile
If the attic roof has a broken structure, then, as a rule, it is not insulated, since the air gap under the rafters protects the premises, while simultaneously ventilating the under-roof space. To do this, when sewing up the gables, you should leave ventilation windows (holes) above the attic floor. Thermal insulation should be done only inside the attic.
Mansard roof insulation The attic thermal insulation device has its own characteristics, since the rooms have triangular or trapezoidal ceilings. Builders consider insulation one of the most difficult technological tasks in the construction of attic spaces. The main thing is to lay the thermal insulation so that it does not shrink during operation on the sloping ceiling and on the fences.
Ksenia Skvortsova. Chief Editor. Author.
Planning and distribution of responsibilities in the content production team, work with texts.
Education: Kharkov State Academy of Culture, specialty “Culturologist. Lecturer in History and Theory of Culture. Experience in copywriting: From 2010 to the present. Editor: since 2016.
Expansion of living space in a private house after construction will cause a lot of problems, including redevelopment and related costs. But if you urgently need an extra room, there is a way out. Do-it-yourself mansard roof, erected above the house, allows you to increase the living space without completing the construction of an additional floor.
The mansard roof is somewhat different from the usual one. Its design is focused on obtaining the desired volume and height of the room. To achieve this goal, the attic is most often made according to a gable broken pattern.
The shape, angle of inclination and design that a sloping roof has are influenced by such factors:
- the height of the snow cover and the maximum level of precipitation in your area - the higher it is, the greater the angle of inclination of the slopes should be;
- estimated thickness of sound and heat insulation - a thick layer of insulation has a decent weight, which entails the need for additional fasteners;
- in some cases, do-it-yourself installation of a mansard roof involves the addition of an external flight of stairs, which can also affect its design.
Technical terms and safety rules
Do-it-yourself sloping roof is assembled from elements, most of which have their own historical names:
- A bar placed along the walls, playing the role of a support for the rafters, is called a Mauerlat.
- The wooden beams that form the slope of the roof are called rafters.
- The stiffeners connecting the individual rafters and distributing the load force between them form a suspension.
- Flat boards, plywood, chipboard and other materials on which tiles, corrugated board or similar roofing material is laid are called purlins.
When working at height, it is very important to take care of your own safety. For this you should:
- use a fastening belt;
- carefully fix the scaffolding during installation;
- do not leave unattended, especially switched on, electric and other tools;
- watch for assistants when lifting and moving heavy loads and it is advisable to always be in their visibility zone;
- do not leave loose parts on the roof slopes;
- try not to be distracted by other things when working at height.
Do-it-yourself attic photo: frame construction
Mansard roofs begin to be built from the base - Mauerlat. It is laid along the top of the walls to bind the box of the house and the roof structure. If the house is not brick, but made of wood, or its last floor is crowned with a wooden part, then the upper log or beam can serve as a Mauerlat.
The connection of the wall and the base in this case is carried out by means of large brackets, powerful overlays, nails or ties. In the old brickwork or concrete wall, the studs or anchors on which the Mauerlat beam sits are driven tightly, and when building a new wall, they are mounted during the masonry process.
Mauerlat is made only from coniferous wood. The bar has a section of 100 - 150 square centimeters. Coniferous wood is distinguished by its durability, resistance to stress and higher resistance to air humidity.
There must be waterproofing between the Mauerlat and the wall.
It can be a layer of thick roofing felt or a durable waterproof membrane. Thanks to waterproofing, the roof with an attic will be protected from excessive moisture and wood damage. When installing the Mauerlat, it is necessary to ensure a strict horizontal of its surface. It will become the basis for setting the verticals and horizontals of the roof structure.
Floor beams are laid on the base so that their ends protrude 30-50 cm beyond the wall line. They are made of coniferous wood, from a bar with a cross section of at least 100x200 mm. The fastening of the beams to the Mauerlat is done with steel corners, brackets and other and durable hardware.
For greater strength at the junction of the bars, you can choose pockets of recesses and lay them with one layer of roofing material. To ensure the horizontal, it is better to first lay the two extreme beams, and level the rest along the stretched cord. Alignment is done by trimming and knocking small wedges, wooden spacers under the bars.
According to accepted standards, the step between the beams can vary from 50 to 100 cm. In practice, do-it-yourself construction of a mansard roof is tied to the dimensions of the materials used, and the step between the beams is adjusted to the width of the interfloor sheet sound and heat insulating material, for example, construction wool. The ends protruding beyond the wall are treated with water-repellent protective preparations.
The racks on which the logs will rest are vertically installed on the floor beams. They are made of timber 100x100 or 100x150 mm. The vertical position of the racks is controlled by a level or a plumb line. The construction of the attic requires mandatory control of the placement of the upper ends of the racks in the same horizontal plane.
Fixing is done by temporary or permanent slopes, both in the longitudinal and transverse directions, in relation to the axial section of the roof. For jibs, any sufficiently strong boards or trimmings of thin timber are taken. The result is two rows of racks, equal in height and parallel to each other.
On top of them, in line with the Mauerlat, runs are laid - boards with a section of 50x150 mm. Usually they account for the fracture of the roof. There are other design solutions, but such a broken mansard roof with your own hands is the easiest to implement.
Runs of parallel rows are interconnected by puffs. The puff-purlin-beam system forms a rigid skeleton of a rectangular living space. Puffs work in tension and do not carry a transverse load. Therefore, for them, you can take the thickness of the board 50 mm, and the crossbar - 150 mm. To eliminate sagging, it is installed on the edge.
rafters
The construction of a mansard-type roof itself begins with the construction of the truss system. With sufficient experience, it is better to assemble the rafters on the ground and feed them upward for their consistent fixing on the girders and Mauerlat. An easier, but time-consuming way is to collect them locally right at the top.
In this case, each board of the lower rafters is applied and cut in place, after which it is attached in the lower part to the base and protruding parts of the beams, and at the top to the girders. Horizontal installation is controlled by a stretched rope. Fastening is carried out with nails, wood screws, steel plates and brackets. The lower part of the rafter leg should extend 30-50 cm beyond the wall. This will be the basis for knocking out the fillies that form the hanging part of the roof.
The upper part of the rafter system is formed by hanging rafters. They can also be collected on the ground and fed up a ready-made corner. After attaching to the lower rafter legs, the ridge of each corner is rigidly attached to the central part of the puff by means of a headstock.
Under its own weight, the upper part of the truss system forms a strong self-adjusting system, similar to an open umbrella. Thanks to this, any fluctuations of the roof will be compensated by springiness. If the width of the attic is large enough, a ridge is knocked along the upper connection of the rafters. With a small width, the extreme upper boards of the crate can play its role.
Sheathing of gables
Sheathing of gables can be done with any sheet material or boards. When they are hemmed, they leave room for window and, if necessary, doorways. They equip a reinforcing frame that matches the size of the window or door frame. At the same time, fillies are pushed to the lower parts of the rafter legs - extension boards that form the overhang of the roof.
The type of lathing depends on the characteristics of the selected type of roof. If it is a soft mansard roof or shingles, then the structure should be solid or with the smallest possible gaps. For a hard coating, their size and lathing pitch are indicated by the manufacturer of specific roofing materials.
Waterproofing is installed under the base for fixing the tiles. It is advisable to thickly treat the boards with a moisture-proof preparation. Plywood and other softwood sheet materials must be water resistant.
Warming
A broken mansard roof allows you to limit yourself to the insulation of the living space from above and on the sides. At the same time, the lower part of the roof will be well ventilated, which will prevent moisture and condensation from accumulating. Due to the rafter voids, the attic with your own hands will be protected from overheating in summer, and from hypothermia in winter.
Attic interior cladding
For the interior lining of the attic space, wooden or plastic lining, plywood, thin sheets of chipboard or fiberboard are used. Heavy facing materials should not be used, since the entire load from their weight falls on the wooden beams.
Outcome
A do-it-yourself attic will most fully meet your requirements and will allow you to make the most of the attic space for organizing living quarters.
Do-it-yourself mansard roof step by step video
broken roof- this is essentially a kind of gable roof. Most often, people choose this design when they want to get more living space on the attic floor. And someone just visually likes this form more than the usual gable.
This article will describe the sequence of erecting a sloping roof when the rafters are supported on the floor beams. Further, I will often refer to previously published articles and. Therefore, I recommend that you first familiarize yourself with their content, if you have not already done so.
So, we start by taking a piece of paper (preferably in a box) and drawing on it the foot of our house with the obligatory observance of scale. Anyone who can draw on a computer is great. Now, based on our personal preferences, we draw (also on a scale) the future roof. At this stage, you need to decide on the height of the structure, with the angles of inclination of the slopes and with the location and size of the window openings.
As an approximate recommendation, I can give you a diagram with proportions that I usually use in my practice. In the figure, the height of the break location of 3.1 meters allows you to ultimately get the final height of the ceilings on the attic floor (with plasterboard trim on the frame) of at least 2.5 meters. The angles of inclination of the side slopes and the upper ones are approximately 60 ° and 30 °, respectively. By the way, the angle of inclination of 60 ° allows you to ignore the snow load when calculating the rafters of the side slopes. All these dimensions are optional and you can adjust them at your discretion.
Now we need to select the sections of the elements of the truss system and calculate them for strength. For this we use the program that we talked about in the article. We calculate the rafters of the side slopes in the tab “Sling. 1″ Having chosen a suitable section, you must also write out from the diagram the value of the vertical reaction force (red arrow up) at the top of the rafter. Let it be "Q1, kg".
We calculate the rafters of the upper slopes in the "Arch" tab. On the schematic, first of all, specifying the value of L, we substitute the value of h0 equal to h. Having selected the section of the rafters, we also write out the value of the vertical reaction force from the diagram, but already at the lowest point of the rafter. It will be designated "Q, kg".
Adding the values of Q1 and Q, we get the concentrated load N, which is transmitted through the racks to the floor beams. We use it when choosing the section of racks and floor beams.
Having decided on all the dimensions, we proceed to the direct construction of a sloping roof. As an example, let's again take a box of a house measuring 8x8 meters:
Step 1:
We install the Mauerlat and floor beams. The details of this process have already been described in the article, so I will not repeat myself. The cross section of the floor beams according to the calculation is 100x200 mm.
Step 2:
We expose the racks along two lines (strictly vertically), first the outer ones from the bar 100x150 mm, then pulling the laces - intermediate ones, with a section of 50x150. The distance between them is no more than 3 meters. We fix all racks with temporary struts. In order not to clutter up the drawing, I showed the spacers on only one rack. We take the height of the racks 10 cm more than the desired height of the finishing ceilings in the rooms.
Now I want to make one important remark. It often happens, especially when a new roof is being made on an old house, that by expanding the floor beams when looking at them from above, we will not get a strict rectangle. The house may be slightly narrowed in any direction. This is not scary, but to facilitate the work, you need to put the racks so that a rectangle is sure to turn out of them. This will allow us to make all the rafters of the upper slopes according to one template. Otherwise, the rafters will have to be placed along the cord and cut in place, and this takes a lot of time and effort.
Step 3:
We put runs from a 50x150 mm board on top of the racks and install the remaining missing racks also with a section of 50x150 mm. No more spacers are needed. The resulting structures will play the role of the frame of the future side walls of the attic room.
Step 4:
We install and fasten on the runs, for example, with the help of roofing corners, puffs (crossbars). Their cross section for this example (the length of the puffs is 5.5 meters), I calculated according to our program in the “Beam” tab in the “Distributed load” plate. At the same time, “Load (normal)” and “Load (calc.)” were taken equal to 150 kg/m². There is no operational load on them.
The calculation showed that with a section width of puffs of 50 mm, the section height should be at least 210 mm. But I still took boards with a section of 50x200 mm. We will eliminate the unacceptable deflection by installing hangers (see below). Of course, this will give an additional load on the rafters of the upper slopes, and therefore, we will increase the cross-sectional dimensions of the rafters of the upper slopes obtained during the calculation from 50x150 mm to 50x200 mm.
When installing puffs (crossbars), we put a temporary support under each of them approximately in the middle of the span. In this case, the resulting sagging can be reduced. It is enough to use an inch 25x150 (only one such support is shown in the figure). They are needed so that when installing the rafters of the upper slopes, calmly walk on puffs, without fear that they will break, and, as I said, to reduce sagging.
Having installed all the puffs, we fasten them on top with a board (25x150 mm). The structure will become more rigid. Do not place this board strictly in the middle. Step back from the axis in any direction by about 20 cm. Why, it will be clear later.
Step 5:
We install the side rafters (left figure). This is done in the same way as described in the article on the gable roof. We also prepare a template, make the upper washed down, mark the lower washed down in place and fasten the rafters.
We install plugs for insulation (right figure). By the way, when I wrote about the gable roof, I completely forgot about them.
Step 6:
We begin the installation of the rafters of the upper slopes.
To begin with, we make a rafter template. To do this, take a suitable piece of board 25x150 and temporarily fix it strictly vertically on the extreme crossbar according to the figure. One of the upper corners of this board (for example, like my right one) should coincide with the geometric center of the roof, i.e. the right side of the board coincides with the axis of the roof (dashed line in the figure). Now we take a suitable board (also an inch, to make it easier), apply it and draw the lower and upper cuts with a pencil.
We make two rafters according to the template and install them. Three people need to work. We do not use a ridge beam here. Having installed the first pair of rafters, we fix it with a brace so that it does not fall.
Next, we put all the other rafters. On a roof like ours (length 8 meters), it will be enough to install four struts, two in different directions. The remaining pairs of rafters, while there is no crate, are temporarily fastened with an inch board (see figure).
Step 7:
According to the picture we sew pendants (board 25x150). They will prevent the puffs (crossbars) from sagging when we remove the temporary props. Now we see why we didn’t put the board fastening all the puffs strictly in the middle. Otherwise, she would be in the way now.
Step 8:
We install the gable frame and sheathe it.
After that, we make cornices, lathing, gable overhangs and gable ebbs. How to do all this, read the article about the gable roof. Again, I will not paint everything over again.
I hope this article will be useful for someone.
Loading...