The attic structure allows you to expand usable space Houses. A structure with a high slope roof will look solid, and its construction will require less effort than constructing a two-story building. The article will talk about how to make an attic roof at home with your own hands.
Types of rafter structures and roofs
How to make an attic roof for a house depends primarily on the intended roof structure.
There are 2 types of roofs for organizing an attic:
- Standard gable. The roof structure has 2 inclined slopes. The pediments in this case are triangular.
- broken roof. Both slopes in this design are further divided into 2. The gables have a pentagonal shape.
How to make a mansard roof
Device of two pitched roof much simpler. But you should understand that the attic in such a design will be small and with low ceilings. Therefore, to complete the task, a sloping roof with a slope angle of 40 to 45 degrees is preferable. And the smaller the slope, the more it will turn out attic room. But in this case, additional strengthening of the structure is necessary, adjacent beams between the rafters.
There are 2 varieties truss structures:
- Layered structures. In this case, only the outer walls serve as support for the rafters.
- Hanging structures . In them, additional strength is given due to the capital partitions on which the rafters rest.
The layered option can be implemented if there are no such partitions. But in this case, the load-bearing walls will have a very high load. Therefore, it is allowed to install layered structures only if the distance between the main walls is no more than 8 meters. If this is not the case, then it is preferable to organize hanging rafter systems.
How to build a roof mansard type with a broken slope? For this purpose, it is mainly installed combined types designs. In them, the upper rafters are mounted in a hanging manner, the rest - layered. This design is most rational for buildings with a low roof slope.
To organize an attic room with ceilings of 2.5 meters, you need to make a roof with a break height of 3.1 meters. The preferred design slope is 60 and 30 degrees. At the top of the rafters, angles from 15 to 45 degrees are possible.
Do-it-yourself Mauerlat installation
In construction, the Mauerlat is the lower support of the roof, which is installed on top of load-bearing external walls. It allows you to support the roof structure, taking on a certain part of the load. Let's figure out how to make an attic roof yourself.
For organization gable design it is necessary to fix the Mauerlat on both sides of the building where the rafters are located. In this case, the load from the roof will be distributed over the surface of the walls. If the roof structure is relatively light, then it is possible to install a mauerlat under the rafters. In other cases, it is placed along the entire perimeter of the walls.
It is necessary to prepare timber from coniferous wood, which will be used to make the Mauerlat. It is recommended to apply a waterproofing layer to the material. Ruberoid or bitumen are excellent for the task.
For installation mansard roof With your own hands, threaded rods designed for a wide washer are used to the base. In its design you need to make holes corresponding to the size of the fastening. The drilling step should not exceed 2 meters.
Now let’s consider the option of how to make an attic roof with your own hands if the house is brick. To install the power plate on brick walls wooden plugs are used. It is advisable to leave pockets in the masonry - special gaps for laying the structure. In this case, the installation procedure will be easier. IN brickwork you can place a wire rod to which you can easily screw the Mauerlat to the base. If you plan to build a house from concrete slabs or aerated concrete, then it is necessary to install an armored belt with metal studs. Moreover, their length should be such that it is enough to install the power plate with subsequent tightening with a lock nut.
In wooden structures, it is possible to replace the standard support with a beam or the top log of a log house. This is another way to make a mansard roof correctly.
Installation of purlins and struts
Purlins are additional horizontally located beams designed to strengthen the structure.
Types of runs:
- Lateral. Such purlins are placed along the entire roof slope. Their number depends on the surface area, as well as its slope.
- Skate. Used as support for the upper part of the rafters. Ridge purlins optional for sloping roofs.
Instructions for building a mansard roof with your own hands step by step:
- The first step is laying the Mauerlat.
- Then you need to place a temporary deck on the roof to make it easy to move around.
- Now the installation of a U-shaped frame of racks, crossbars and purlins is underway.
- When the frame is completed, 50x150 mm rafters need to be laid on it. The braces will add rigidity to the structure.
Installation of rafter legs
There are 2 types of rafter fastening:
- sliding(it is also called hinged). It provides so-called skids in the mount, along which the rafters move along the mauerlat. It is suitable if there is a possibility of settling at home.
- Hard. In this case, staples with bolts or wire with nails are used for connection.
The option of how to properly make an attic with a sliding fastening demonstrates greater reliability, since it takes into account the mobility of roof elements when the ground subsides. Sliding mount will be useful in the construction of a wooden house, for which shrinkage is possible. It will help the roof “adapt” to the movement of the building.
How to build a roof correctly
Recommendation: to understand the location upper rafters, it’s worth making a temporary stand from beams. It is attached to the Mauerlat so that its top is located along the center line of the roof. This design will be a hint when aligning the upper rafters, which will greatly facilitate the task.
It is necessary to make the upper part of the Mauerlat beveled. It is advisable to first make it from a thinner board. Then you need to attach it to the purlin and trace its contours. And then fill in the form according to the received form. This approach will allow you to do the work more accurately. Now you know how to build an attic roof with your own hands.
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Attic construction attic space allows not only to increase living space home, but also to make the building unusual and beautiful. Moreover, a building with this type of roof can be made in almost any style. The mansard type roof, the design options of which can be very different, is found both in urban areas and in rural areas. Let's look at how to create such a design yourself, and find out what its features are.
Mansard roof - options
This roof has a special slope design, usually consisting of a flat upper part and a steeper lower part. Thanks to this shape, a fairly spacious room appears inside, which can be used as an attic or even turn into a very cozy living room.
The history of attics began in the 17th century, such a roof design was invented by the architect Francois Mansart - it was a derivative of his name that such a roof was named. But this Frenchman was far from the first to implement the idea of economical use attic floor Houses. The mansard roof was first built by Pierre Lescot, also a Frenchman, who worked on the construction of such famous buildings as the Louvre and Notre-Dame de Paris.
On a note! In the 19th century, poor people usually lived on attic floors, but now this floor can appear in the housing of fairly wealthy people.
Nowadays, attics are quite often constructed during construction. country houses or small two-story cottages, but the idea may well be implemented when creating other types of buildings. The attic has a number of advantages:
- it is cheaper to build a house with an attic than with two full floors and a roof;
- foundation costs during the construction of such a structure are also reduced;
- an attic can significantly increase the living space of any building;
- it gives the house an unusual and beautiful look;
- it is not difficult to build the structure, the work can be completed quite quickly;
- the attic is always associated with comfort;
- a house with an attic is warmer by reducing heat loss through the roof.
But attics also have several disadvantages. This type of attic space has sloping ceilings, which results in low wall heights, making it difficult to choose furniture. Also, the roof must be well installed so as not to leak and not let heat out of the house - you will have to spend money on good hydro- and thermal insulation materials. And building attics is still more difficult than, for example, a regular gable roof.
Design Features
The attic is a universal element. It was used both for ordinary houses and for the construction of country houses; often this type of attic space was chosen even for the construction of palaces. Of course, it could decorate workshops, commercial buildings, etc. And despite the fact that they were used for its construction different materials, were chosen different styles, the attic still remained an attic - it has certain design features.
So, this building can have a different geometric shape - triangular, broken, have symmetrical or, conversely, geometrically complex and non-standard slopes. It can be located both across the entire width of the building, and only on one side of it relative to the longitudinal axis.
Prices for timber
On a note! If the roof has a broken shape, then the lower part will have very steep slopes with an inclination angle of about 60-70 degrees, and on the top the slopes, on the contrary, will be flat (about 15-30 degrees).
But whatever the attic, it will be located within the walls of the main building. In relation to the external walls, the attic may be slightly wider, but then it rests on the ceiling extensions. If the offset is large, then you will have to install additional supports (for example, columns, walls, etc.).
Height mansard roof it cannot be less than 2.5 m, otherwise it will not be possible to create a spacious room under it. Windows, which also need to be provided here, will be manufactured using special technologies using durable tempered glass and a reliable frame. They will cost several times more than usual. A bearing structures can be made of reinforced concrete, metal or wood. But in the case of the latter, it is important to carefully consider fire safety measures.
The mansard roof is a multi-layer structure, which complicates installation. It can be insulated completely or only in the area where there is a living room - where there is heating. But in any case, the design of the attic implies the presence of rafters, a ridge, the roofing material itself, thermal and waterproofing, and a vapor barrier layer. The interfloor ceiling will serve as the foundation under the roof.
Rafters for an attic roof must have good load-bearing capacity. The cross-section of the materials used will depend on the angle of the roof slope and cannot be less than 5x15 cm at a pitch of 100 cm. If the slope angle is 45 degrees, then a pitch of 140 cm is maintained.
Attention! In areas where it snows frequently and the amount of precipitation is high, it is recommended to install rafters at intervals of no more than 80 cm.
If the attic will be used as a living space, it is important to consider that in this case there is a risk of formation large quantity condensation under the roof. Because of this, pockets of mold may appear inside the structure, fungus may develop, etc. The presence of a large amount of moisture will also negatively affect the insulating properties of the material. That is why it is important to follow all the rules for installing an attic roof, and the heat-insulating material must be reliably protected from moisture not only from the outside, but also from the inside, that is, a layer of vapor barrier material is also located on this side.
Important! Don’t forget about creating roof vents that will allow air to circulate quietly inside the roof structure and help remove condensation.
Types of mansard roofs
There are 4 main types of mansard roofs, which differ from each other in their design features. They can be divided into single-level and two-level. The first are the simplest to implement, usually combined with a sloping or gable roof with a slope angle of 35-45 degrees. The second involves the arrangement of two rooms at different levels. A mixed support system is used here.
On a note! When building an attic under a gable roof, the height of the walls can be no more than 1.5 m, followed by sloping ceilings. With a broken-shaped roof, the ceiling height along the perimeter of the walls is up to 2.5 m.
When building a house, you can choose one of the types of attics - a single-level attic with a gable roof, a single-level with a sloping roof, with external consoles, or a two-level with a special mixed type of supports.
Table. Main types of attics.
| Type | Description |
|---|---|
| In this case, the attic has one level and is located under a regular gable roof. The simplest option, the design of which does not require the use of complex calculations. Rainfall with a simple gable roof goes away on its own, there is no need to equip any additional elements. |
| In this case, the attic also has one level, but the rafter system is performed differently. It looks like four roof slopes are formed. A much larger room can fit under it, but creating such a roof is more difficult. |
| Of the single-level attics, this is the most difficult option. Here the room under the roof is even more spacious. Usually in this case the attic room is shifted to one of the edges of the house. This design allows you to make large vertical windows on one side. Main disadvantages – complex shape, complexity of construction. But under the edge of such an attic you can make a functional canopy where a terrace, garage or other extension can be located. |
| The most difficult option is the attic, since at least two rooms under the roof are arranged here, located at different levels. When designing a house, such a design immediately becomes part of its structure. |
The attic roof can also have a balcony. It is created according to the principle of window construction. The main thing is that the load-bearing capacity of the walls allows it to be equipped. By the way, the balcony can also be supported by columns, but in this case it is built above the entrance.
Types of rafters for attics
Rafter trusses can be of two types - and layered. You will have to choose between them depending on the method of attachment to the walls of the house. Hanging ones are simpler and are usually used for houses that do not have a middle load-bearing wall. The rafters rest only on the main walls of the house, without intermediate supports. The width of the span between the walls cannot be large - usually it does not exceed 6 m. If the span is larger (over 9 m), then it will be necessary to install struts and headstocks.
Layered rafters are usually used when creating houses with two spans, that is, those that have load-bearing wall in the middle. In this case, the rafters have three support points - directly this wall, as well as the main ones around the perimeter of the house.
Material for the manufacture of the rafter system
Rafters can be made of metal, reinforced concrete or wood. Each material has its own advantages and disadvantages. Wooden rafters are environmentally friendly, they are easy to use, and can be easily adjusted to the desired size. But wooden structures They are afraid of excess moisture and are susceptible to the formation of mold and mildew.
On a note! It is recommended to treat wooden materials before construction protective compounds, which will extend their service life.
Metal and reinforced concrete structures You can not cover them with such compounds - fungus and mold do not appear on them. Due to this, they are considered more reliable and durable. But the main disadvantage is that, if necessary, adjusting them on site to the right sizes It will be difficult, and the slightest error in the calculations can lead to the fact that the roof will be skewed. Also, a craftsman working with reinforced concrete or metal rafters may encounter other difficulties - this is a large mass of products, which forces the use of special equipment even to lift the elements.
Difficulties and features of arranging an attic roof
When designing and constructing an attic roof, a number of design features should be taken into account, based on which a number of operating rules are formed. For example, the Mauerlat must be secured very securely with anchor bolts. It is he who will experience maximum load, which means keeping the entire roof on itself. It is additionally recommended to wall up the anchors cement mixture, if the main walls of the house are made of stone, brick and other similar materials.
It is also important to remember correct design and layers of the roof. For example, mansard roofs cannot be covered with metal roofing materials. They get very hot and top floor in the summer it will be too hot, there can simply be no talk of any comfortable living. It is not recommended to use roofing felt as a waterproofing material - when heated, it begins to smell specifically. It is best to cover the attic roof with slate or soft tiles. For thermal insulation, it is usually recommended to purchase mineral wool, which is laid waterproofing film on both sides.
An attic, which makes it possible to effectively use the floor space of a private house, is a rather complex design. As a rule, homeowners entrust its construction to experienced roofers. But if you are skilled in carpentry and are not afraid of difficulties, then you can certainly cope with the task yourself. The first step is to obtain theoretical knowledge of how an attic roof is calculated and built with your own hands according to individual drawings. You will find this information, presented in the form of a step-by-step guide, in this article.
Choosing a roof design
For the installation of an attic floor, instead of a conventional attic, they are suitable following types roofs (shown in the diagram below):
- regular gable with a slope of 45° or more (steep);
- broken roof;
- four-slope, half-hip.
Note. As can be seen from the diagram, various half-hip roofings are complicated gable roofs, so there is no point in considering them separately. In terms of design, the multi-gable structure shown in the photo is of interest, but its construction requires considerable experience.
The gable mansard roof is the simplest to implement and is economical in terms of material consumption. But you will have to pay for this with a smaller usable area and sloping walls of the attached floor, which do not allow the placement of tall furniture. This will not be a problem if you plan to set up a bedroom in the attic - the beds will easily stand near the longitudinal walls. Another way to solve the issue is to raise the rafter system to the required height, as shown in the drawing below.
Roofing with broken shapes is the most popular option, since it allows you to create full-fledged living rooms upstairs. If you do not provide protruding windows on its slopes, then in terms of installation technology such a roof is not much more complicated than a gable roof, although the consumption of building materials will increase. To make your choice easier, we suggest considering and comparing the 3 most common options for an attic superstructure for a private home standard sizes 6 x 6 m:
- Steep roof with two slopes inclined at an angle of 45°.
- A broken structure, where the lower rafters are inclined at an angle of 60°, and the upper ones - 30°.
- The same as option 1, only the trusses are raised to a height of 60 cm, and the rafter legs are at an angle of 37.5°.
For convenience, we depicted all three structures on one drawing, which can be taken as a basis for future construction.
Note. Boards were used as the main building material for the manufacture of rafters and other frame elements. cross section 50 x 150 mm.
To choose the best of the three options, we suggest studying comparison table, where the parameters of attic rooms are presented based on 1 linear meter building length.
Knowing the length of the roof slopes indicated in the plate, you can approximately estimate the consumption of building materials for the frame, covering and insulation. The following table allows you to evaluate total area rooms on the second floor when implementing all 3 solutions in private houses of different sizes.
Calculation of the rafter system
The rafters of a do-it-yourself attic must withstand the following loads throughout their entire service life:
- own weight;
- weight of roofing and insulation;
- maximum gusts of wind for a given area;
- snow cover pressure.
Reference. When the roof slope is more than 45°, snow practically does not stay on it, and at 60° it is not taken into account at all in the calculations. But wind pressure increases due to the height of the structure and its position, which is close to vertical.
The result of the calculations should be 2 parameters - the cross-section of the rafters with beams (otherwise known as tie rods) and the pitch of their installation. It is a mistake to think that the size of the wooden beams of the roof grows along with the loads on it. Maximum structural rigidity is achieved through the use of trusses made from logs with a diameter of 120-200 mm or lumber with a thickness of 40 to 200 mm, installed in increments of 50-120 cm. If you are not a civil engineer, you will not be able to determine these values more precisely, since the methodology quite complicated.
Online calculators posted on the Internet do not solve the issue, because their calculations still need to be checked. The solution is this: use ready-made data that has been calculated a long time ago. To do this, you will need table No. 1, which shows the cross-sections of rafter legs at different lengths and loads:
We will explain the calculation method with an example. Let us assume that the snow load is flat surface(projection of a pitched roof) in your area is 100 kg/m², the slope is 60°, the span length is 4.5 m (before the brace), the pitch of the rafters is 120 cm. The roofing is slate. We count:
- Real weight of snow cover: 100 x 0.32 = 32 kg/m². The slope coefficient of 0.32 is taken from Table 2 below.
- The specific gravity of a slate covering with a regular profile is 25 kg/m².
- General specific gravity– 32 + 25 = 60 kg/m².
- We calculate the specific gravity per 1 linear meter of rafters, multiplying 60 kg/m² by an installation step of 1.2 m. We get 72 kg.
- We return to table No. 1 and select the cross-section of the beam according to the span length. We accept a load of 100 kg per 1 line of rafters (with a margin). A log with a diameter of 140 mm, a board 40 x 200 mm and other materials whose dimensions are in the same horizontal line are suitable.
Reference. When installing a sloping mansard roof, 2 types of rafters are used - layered and hanging. On gable roof Only hanging ones are used; the difference between them is shown in the diagram.
The last table No. 3 will help you correctly determine the installation interval of roof trusses:
The proposed method is suitable for small houses rectangular shape dimensions 6 x 6 m. To build a mansard roof on a large cottage, it is strongly recommended to contact specialist designers for calculations.
Frame making
The simplified method presented below involves the installation of an attic sloping roof in 2 stages: assembly of roof trusses on the ground and subsequent installation on finished walls timber or log house. Construction material boards with a section of 15 x 5 and 10 x 5 cm with a standard length of 6 m stand out.
Start of assembly - formation of the upper chord of the rafter system
The technology looks like this step by step:
- Prepare the beams of the lower chord of the truss, taking into account roof overhangs of 25-27 cm on each side. If the length of the beam is not enough, it needs to be increased using an overlay of the same section, nailed.
- Lay the beam on the ground and attach it to it with corners vertical racks, forming the walls of the attic room. Install ceiling beam and a support for the ridge (headstock), then attach two boards of hanging rafters to it and the corners of the frame for marking, as was done in the photo.
- Cut the elements into place and secure them. From the remaining parts of the boards, make layered (lower) rafter legs in the same way and nail them to the frame. The farm is ready.
- Make the remaining trusses using the same method.
Advice. As a rule, windows or doors to the balcony are provided on the front gables. It is also convenient to make racks and belts for their installation on the ground, as well as to cover the openings with clapboard.
How to quickly and accurately assemble rafters for the attic is described in the video:
The finished frames are lifted onto the walls and fixed in place one by one, starting from the first gable. To prevent it from falling, install spacers and nail them to the walls of the log house. The second and subsequent trusses are placed in the design position and connected to each other with boards.
After placing the rafters, they must be secured to the walls in the following ways:
- staples to the second top crown of logs or beams;
- on steel corners and galvanized screws, as shown in the photo.
Note. Installation on brick and other capital walls performed via Mauerlat - wooden beam, laid on supporting structures along the entire perimeter of the building. In turn, the Mauerlat is mounted on studs or anchor bolts, and between it and the stone wall a waterproofing layer of roofing felt is installed. The mounting assembly looks like this:
The next step is to lay a diffusion membrane on top of the rafter system - a film that protects from wind and precipitation, but allows water vapor from the insulation to pass out. Roll out the first sheet at the bottom of the roof and secure it to the boards with a stapler, lay the next one with an overlap of 10-15 cm. When you have covered the entire roof, nail the sheathing boards. The installation is shown in more detail in the video:
The roofing covering is laid on top of the sheathing - slate, metal tiles, and so on. The technology of installation and fastening depends on the selected material.
Attic insulation
Since the attic space is planned as a residential space, it should be well insulated. From thermal insulation materials Mineral wool works best with wood because it allows moisture to pass through and allows it to “breathe.” The layer thickness is at least 150 mm, and in the northern regions - up to 300 mm. Insulation is carried out in the following order:
- Cut the mineral wool slabs and insert them spaced between the rafters.
- To insulate the gables, nail additional posts and lay insulation between them in the same way.
- If the width of the rafter legs is not enough to create thermal insulation of the required thickness, after laying the first layer, nail horizontal counter-lattice bars to them. Insert the second layer slabs between them.
- Cover the insulation from the inside vapor barrier film, laying it with an overlap of 15 cm and gluing the joints with aluminum tape.
- Nail the sheathing strips on top for cladding with plasterboard or other finishing material.
Important point. When laying insulation, make sure that between it and windproof membrane a ventilation duct of 3-5 cm remained. Through it, the moisture formed in the mineral wool due to the occurrence of the dew point will be removed.
The process of thermal insulation of the attic is clearly shown in the next video:
Conclusion
Construction of an attic roof is a labor-intensive task and you cannot overcome it alone. Most work needs to be done with an assistant, and lifting trusses will require 3 people. Also, the success of your event largely depends on the correctness of the initial calculations. If the calculation method confuses you, and there are no smart engineers nearby, consult with experienced roofers, whose competence there is no doubt. They will suggest the right solution and, perhaps, tell you about the details of installing such systems.
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After lofts came into fashion, that is, essentially, attics converted into housing, sloping roofs became extremely popular. This is a kind of variation on the theme gable roof, but with a slightly more complex geometry. By installing a sloping roof in your home, it becomes possible to increase the useful living space of the attic - significantly raise the ceiling at the extreme points of the slope. In addition, as many believe, such a roof looks more unusual and much more impressive than a simple gable roof.
The construction of a sloping roof is somewhat more complicated than a gable roof, but easier than any four-slope roof - hip, half-hip, hipped, as well as others with more exotic geometry. However, before you begin to study this topic, it is recommended that you familiarize yourself with the basic terms and concepts and learn how to build simpler roof options - single-pitched and gable.
Broken roof: where to start
In construction, even a doghouse cannot be built without planning, so the zero step in constructing a sloping roof will be drawing a drawing. It can be done on a computer or manually. First we build frontal projection feet (the foot in short is the foundation of a house without a roof) of our house. Now, also observing the proportions, we build on the drawing the roof we like. Don’t forget that there will be an attic underneath it, so you need to think about the height of the ceilings in it. This way we will get the approximate roof height, slope degree and other parameters.
On the proposed plan the break is located at a height of 3.1 meters, which, in fact, will be (conditionally, without taking into account the under roofing pie) final ceiling height in the attic. If the finishing is done with plasterboard, then in the end attic floor the ceiling will be about 2.5 meters - quite good. The outer angles of the slopes with the horizon are: ridge - 30°, side - 60°. By the way, if the angle of the slope is 60° or more, then the snow load may not be taken into account in the calculations - the snow will not be retained on it. Your own drawing may have other options.
Calculation of the components of the rafter system
To prevent our roof from collapsing under its own weight and the weight of the “roofing pie,” we need to accurately select the cross-sections of the beams and boards of the rafter system, and also calculate their maximum strength. To do this you need to use a special program " Calculation of rafters and floor beams».
To calculate the cross-section of the beams of the side slopes, you need to open the tab (they are at the bottom of the window) “Sling.1”. Next, we establish a suitable section and introduce from plan of our house is an indicator of the vertical reaction force (in the picture in the program it is a red arrow pointing upward) at the highest point of the rafters. Let's call this indicator Q1 kg.
When installing tie boards, under each one, somewhere in the middle of the length, we install a temporary support. This allows you to reduce the degree of sagging. You can use supports 2.5x15 cm (in the illustration you can see a support for only one puff). They are necessary so that during the installation of the rafters there is no fear that one of the beams will break, and also to prevent sagging.
We put a 2.5×15 board on top of the ties, which will tighten them and make the entire structure more stable. Important: this board cannot be installed exactly in the center - it will interfere with further installation. It will be enough to step back from the central axis about 20 cm to the right or left.
Now we install the side rafters as shown in the illustration. We do not forget that, despite all our efforts, the geometry of the roof base may not have been ideal. Therefore, first we make a template along the end beam. Then on all subsequent rafters we make only the top cut. After this, we place the rafter in the place we need and only then we finally file it down. Only after this we fasten the rafters.
If the length of the beam is not enough, it can be extended, but an additional stand must be placed under the joint.
Now you can install the plugs for insulation material as shown in the illustration.
Next, you can install the rafters of the upper ridge slope. We make a temporary stand: take a 2.5×15 board and place it exactly perpendicular to the extreme tightening, as done in the illustration. The right (or left) edge of the board should be aligned exactly with the center axis. Now we take a board of the same cross-section and attach it to our B-pillar and with a pencil we make marks where the upper and lower cuts will be - we have a template.
The attic roof makes it possible to significantly increase the total living space, while the financial investment will be minimal. The most common option is a gable broken structure, which is easy to build yourself.
How to make a mansard roof yourself
Under the attic roof you can arrange living rooms. The shape of the building can be different, but in most cases the attic is built under a roof with two slopes. The optimal solution, which allows you to obtain a significant area of living space, is a broken structure.
Broken roof is the best option for arranging an attic
Drawings and calculations of a mansard roof
The first step is to decide on the frame diagram. Rafters can be layered or hanging type. Layered ones rest on the walls of the building. They are mounted in structures where the distance between the walls is less than 6.5 m. Hanging rafters are placed on fillets and a mauerlat. If the width of the spans is large, then the rafter system will need to be reinforced with auxiliary ties.
The main condition for the comfortable construction of an attic is the ceiling level - it must be higher than 2.5 m. To ensure a similar height, the break line must be placed at a height of more than 2.8 m, taking into account the thickness of the layer of material for insulation and cladding of the structure. It is also important to consider the thickness of the floor.
An example of a drawing can be seen in the image:
The minimum ceiling height of the attic roof is 2.5 m
To calculate the expected snow loads, you will need to apply this formula: S = Sg x µ, where S is the snow load, Sg is the weight of the snow cover per 1 m 2 area, µ is the value that depends on the roof slope (1.0 - for flat design with a slope of 25°, 0.7 - for a design with a slope of 25–60°).
Parameters Sg and Wo can be found in the relevant SNiP, in the “Rafter systems” section. If the roof has a steep slope, then the snow load can be ignored.
Roof structure
The frame structure includes the following parts:
- Mauerlat - a support bar that transfers the load from the rafters to the walls of the building;
- racks - supporting parts that support the rafter system in a vertical position;
- floor beams - planks that form half of the attic and the ceiling of the lower floor;
- rafters - slats that form the main contour of the roof;
- purlins - horizontal supporting parts for rafters;
- sheathing - slats or plywood sheets that are intended for laying roofing material;
- fillies - strips that are attached along the axis at the bottom of the rafter legs.
The frame consists of a mauerlat, racks, purlins, floor beams and other elements
A sloping roof differs from an ordinary structure with two slopes. The difference is that the slopes, which are placed opposite each other, have a special shape: they form no straight line, but consist of several slopes, which are fastened to one another at an obtuse angle. The design is also symmetrical.
The extreme part of the rafters is generally set at an angle of about 60°. The support posts that support the rafters form the frame structure of the interior walls. The upper part of the rafters is mounted at a small angle, it can be from 15 to 45°. This makes it possible to reduce material consumption, while maintaining the functional properties of the roof and resistance to loads from snow.
Vertical posts that rest against the floor planks, purlins and crossbars that fasten them form a parallelepiped. The design limits the dimensions of the attic from the inside. To give the product additional rigidity, struts should be installed between the floor slats and the lower rafters.
If the roof span is more than 8 m, then you will need to install struts
After installing the upper elements, to fix the truss and prevent sagging of the crossbars, you should install hanging support elements - headstocks. For auxiliary fixation of the lower rafter legs, they must be pulled together with the uprights using tacks. The parts are fastened using nails and bolts.
Stages of self-construction of an attic
If the decision is made to make similar design yourself, in the project it is important to provide for the use of such materials:
- roofing material;
- vapor barrier;
- waterproofing;
- insulation material.
The choice of insulation affects such a parameter as the pitch of the rafters. To reduce the amount of insulation, it is best to place the rafters so that the slab or mat fits tightly between them. The type of sheathing and its pitch will depend on the choice of material for roofing. You need to pay attention not only to choosing high-quality material for insulation, but also to creating an effective ventilation system.
Ventilation is arranged by preparing technological gaps
The construction of the rafter system must be carried out using fireproof materials. All parts should be treated with fire retardants. You will need to prepare the following elements:
- wooden blocks with a cross section of 100x50 mm;
- slats 50x150 mm;
- unedged boards;
- building level;
- self-tapping screws;
- nails;
- steel wire with a diameter of 4–5 mm;
- plumb line;
- roulette;
- hacksaw;
- axe;
- hammer;
- sharp knife.
Drafting
One of the most important parts of the work is drafting the project. It is very important to analyze the layout features of a private house. It is necessary to determine the dimensions and shape of the structure being built, and also provide for the placement of windows and a balcony.
All structural elements should be marked on the project
In the process of drawing up a project, the following requirements must be taken into account:
- It is important to decide in advance what the height of the attic should be. It should be remembered that the distance from floor base to the highest point of the structure there should be a minimum of 0.5 m.
- It is recommended to take into account the heating area and the main interior elements.
- The attic layout should be expanded. If you plan to install windows, they must be indicated on the drawing.
Drawing up a drawing must begin with choosing a shape, determining the cross-section of the rafter legs and the step of their placement. To determine the size of the rafters, you need to take into account the following parameters:
- slope;
- roof roofing material;
- climate features in the construction region.
It is also important to provide the required number of rafters in the project. They can be layered or hanging type.
Rafters can be hanging or layered
At the end, you should determine the number of parts to fix. In the figure below you can see some of the data necessary for the calculation, but drawing up a project is a complex process. This work It is recommended to entrust it to qualified specialists.
Mauerlat installation
The design of the attic roof rafter system should be selected based on the type of roof, as well as the prepared attic design. A simple option is a design with two slopes.
The main details of a roof rafter system with two slopes are:
- linear elements (column, rod system, beam);
- flat parts (slab, flooring, panel);
- spatial elements (vault, shell, volumetric part).
Before carrying out work, you will need to thoroughly dry the wood. The first step is to mark and install the Mauerlat. It is fixed to the walls of the building. The part can be made from a block or a powerful lath. If you plan to build a roof with two slopes, then the Mauerlat is laid on the long walls of the building. The element is necessary not only for reliable fixation of the lower part of the rafters, but also for the correct distribution of the load on the walls and the main part of the building.
To fix the Mauerlat, you should use metal pins that are attached to a beam made of monolithic concrete.
To fix the Mauerlat, you need to install metal pins
The beam should be placed at the top of the wall. It is also possible to use steel wire embedded in brickwork.
To secure the Mauerlat to the upper rim of a wooden wall, you need to use wooden dowels. Auerlat requires execution high-quality waterproofing wooden beams. Therefore, it is necessary to use roofing felt or other material with water-repellent properties.
Before installing the Mauerlat, the base must be covered with roofing felt.
The installation of a Mauerlat is required if it is planned to construct a roof frame, the rafters of which rest against the upper part of the wall with beveled ends or prepared cutouts.
If you plan to make an attic, the width of which corresponds to the width of the building, the rafter legs should rest with their lower ends against the external supporting parts. It is possible to use powerful beams laid across long walls as supports. The number of supporting elements corresponds to the number of rafters. The beams must be secured to the walls in the same way as the Mauerlat.
Sequencing:
Frame construction
The frame of the attic roof consists of floor beams, rafters, purlins and racks
The material used is often 200x100 mm softwood bars. The floor slats are placed on top of the mauerlat with an indentation of 30–50 cm beyond the surface of the walls or into prepared grooves in the masonry. In the first case, the parts are fixed using angles and self-tapping screws.
Fixing the timber to the mauerlat can be done using steel corners
To make an even floor, the planks should be installed in this sequence:
- First of all, the outer parts are placed level.
- Next, you should tighten the cord and install intermediate elements along it.
- The pitch of the beams should be from 60 to 100 cm. A distance of 60 cm makes it possible to install insulation boards without cutting.
- To level the beams in height, they can be trimmed. Another option is to use plank underlays.
- If beams are inserted into prepared pockets, their outer parts must be processed liquid waterproofing and wrap it in roofing felt.
You need to place the racks on the outer planks:
After installing the racks, crossbars and purlins, you can get reliable design, which will limit interior rooms attics. To increase its strength, it should be secured in the future with struts and tacks.
Installation of rafters
At this stage, the installation of the lower rafters is carried out:
After this, the upper elements are installed:
- The first step is to mark the central part of the roof. This can be done using a stand that was previously attached to the Mauerlat and a tie from the end of the roof. The outermost part of the board should run along the center of the roof. The rafter legs need to be aligned along this board.
- Next, you need to prepare a template from a 150x25 mm slats. It should be applied to the extreme part of the mounted batten at the required level and to the purlin on which the lower rafter legs will rest.
- You should mark the upper and lower cuts and cut out a template. The device is applied in turn to two sides of the roof. This will make it possible to check the accuracy of the marking of the central part. If the rows of racks are placed in parallel, then there will be no difficulties in securing the upper elements - they will have identical dimensions.
- According to the preparation, you need to prepare the required number of rafters. The parts are placed on purlins and tied together in the upper parts using iron plates or trim strips. In the latter case, self-tapping screws are used as fasteners. In the purlin, the rafter strips rest against the cuts and are caught with iron corners. To ensure that the parts stand straight, they are secured using struts, mounted with the lower part on ties. All rafters are installed using this method.
- The hanging racks are fixed - pieces of 150x25 mm planks. The upper part of the batten is attached to the place where the rafters are fixed, the lower part is attached to the tie.
Video: mansard roof rafter system
Installation of struts and gables
Sequencing:
Sheathing of the structure
The sheathing is needed for:
- distribution and transfer of the weight of the roofing material to the rafters;
- performing additional fastening of the rafter system;
- bases for fixing roofing material.
The sheathing can be made in one or two layers, continuous or with vacuum.
The sheathing can be solid or with relief
The installation method depends on what material is planned to be used to cover the structure. If a roof is being built from slate or metal tiles, the sheathing should be made of slats that are attached to the rafters with nails. In this case, the installation step of adjacent planks can be 27–30 cm.
Continuous sheathing is used in case of fastening soft material in rolls.
Solid sheathing is necessary for a soft roof
In this case, you can use moisture-resistant plywood sheets or particle boards. It is allowed to use pine wood material- trim strips.
It is important to take into account the fact that when installing such a sheathing, the material that will be laid must follow the contours external base. That's why frame construction must be strong and level.
When laying out the material, you should use a cord, with which the slats or slabs will lie flat. The parts must be placed parallel to each other. Before fixing, the material must be treated with an antiseptic composition to protect it from rotting, fungus and dampness. The workpieces must be smooth and of high quality. It is recommended to give preference to wood grades 1 and 2. There should be no knots on it. To prevent the boards from warping, they must first be dried.
Sequence of actions for installing the sheathing:
Waterproofing a mansard roof
Roofing material does not have thermal insulation properties, so you will need to prepare quality material, which will be environmentally safe for human health. Quite often mineral wool or glass wool is used. Both materials have excellent sound and heat insulation parameters. It is also important to take into account that if the roof is made of metal, if the insulation gets wet, all its qualities can be reduced to zero. Therefore, it is important to carefully consider the design.
It will not be possible to insulate an attic without laying waterproofing material, so the process should be considered in its entirety. Step by step guide for waterproofing the structure:
Practice has shown that it is better to protect insulation with modern materials, for example, Tyvek or Izospan. The use of ordinary polyethylene film gives poor results, as condensation may appear. Experienced craftsmen They believe that the structure should not be waterproofed with roofing felt.
Before proceeding with the work, you need to decide on the thermal insulation material.
Mineral wool is a fairly popular material used for roof insulation.
The most commonly used heat insulators are:
- glass wool;
- mineral wool;
- Styrofoam;
- foam glass;
- wood shavings;
- straw.
The material must be selected taking into account four parameters.
- Thermal conductivity index. For roof insulation, 0.05 W/m*K or lower is optimal.
- Water resistance. The higher the score, the better.
- Fire resistance.
- Environmental Safety.
The insulating qualities of mineral wool deteriorate significantly after some time. The material can also be damaged under the influence of mechanical loads. However, mineral wool has a low cost, so the material is used quite often. Polyfoam is not afraid of water and has excellent thermal insulation characteristics. If you plan to build a house only from environmentally friendly materials, then you can use foam glass or straw.
Step-by-step guide to roof insulation:
Laying roofing materials and installing window openings
As an example, we will consider the installation of metal tiles, since this material is used quite often:
The number of windows is determined by the relation usable area glazing to the base of the floor 1:10. For example, if the attic area is 100 m2, then the glazing should be approximately 10 m2. When installing windows, you need to consider the following nuances:
Attic finishing
The interior decoration of the attic can be done using wood or plasterboard sheets. If the latter option is used, then after installation the sheets must be covered with wallpaper or painted. water-based paint. In some cases, the attic is divided into several rooms. This can be done using plasterboard partitions.
If you plan to use the attic frequently, then the floor and walls can be additionally insulated. This can be done using, for example, mineral wool.
Interesting attic room design options
The attic can be made cozy by symmetrically arranging sofas on both sides. In the attic you can place a long sofa. In the attic you can create a place to relax by hanging a hammock. In the attic you can make not only a living space, but also a bathroom. On the attic floor you can even make a kitchen. If on the territory it is not possible to place a hammock, then this can be done on the attic floor. One of the parts of the attic can be completely glazed. The attic can be an excellent place to create a home library. The walls of the attic can be lined with brick. In the attic, you can arrange a full-fledged living room. On the attic floor, you can arrange a rest room. in a beautiful area, the roof can be made panoramic The bed can be positioned front part to the window In the attic you can make a bedroom with high ceilings In the attic you can place a hanging chair. This will make the roof more comfortable
Video: making a mansard roof
Recently, the mansard-type roof has become quite popular among owners of private houses. To experience all the positive aspects of living in a building of this type, you need to pay due attention to the insulation of the building.