The attic is an excellent opportunity to increase the total and usable area of the house. It is installed in the attic and is quite suitable for living, provided that it is designed correctly. The rafter system of the attic roof, drawings of which can be found in this material, is the basis of the entire structure. And it is precisely this that needs to be given the closest attention when designing.
Mansard roof rafter system - drawings
An attic is a room located directly under the roof. Its facade is partially or completely formed by the roof surfaces (according to SNiP 2.08.01-89).
SNiP 2.08.01-89. Residential buildings. Downloadable file (click the link to open the PDF in a new window).
It is a full-fledged residential floor; there can be one or several rooms, depending on the design parameters.
Note! The word "attic" comes from France. It was the French architect who, in 1630, came up with the idea of usefully arranging attic spaces. And this man’s name was François Mansart - hence the name of this type add-ons.
The peculiarity of attic roofs is not only the special design rafter system, but also the need for detailed consideration of other aspects - insulation, moisture and vapor barriers, etc. Since the attic usually increases the load on the foundation and walls of the building itself, all its elements are mainly built from lightweight materials. That is, it is recommended to use wood to create a rafter system; lightweight materials are used as insulation.
The attic can be of impressive size and occupy the entire area of the building, but within its walls. Sometimes it is installed only on part of the floors, and then the rear ones are covered by a regular roof.
Very often the attic is used in individual construction, because this is an opportunity to increase living space home, make it warmer (heat loss through the roof is reduced by an average of 7-9%). And the costs of arranging an attic will be much less than building a full floor.
In general, building an attic is not very difficult and you can cope with the task yourself. The main thing is to correctly calculate wind, snow and other types of load.
Prices for timber
Types of attics
The design of the attic will directly depend on what shape the roof is supposed to be installed. After all, part of the walls of this room will be formed by the roof slopes. Depending on this, there are several types of mansard roofs.
Perhaps the simplest option is to arrange the roof itself and attic floor. This roof has only one slope, which rests on the multi-level walls of the building. Thus, the slope angle is formed. By the way, it should not go beyond the strictly limited limits - 35-45 degrees (if the slope is less, then snow will constantly accumulate on the roof). winter time, which will significantly increase the load on the entire house and will cause the installation of additional supports in the already small attic). The rafter system here is extremely simple.
Note! The rafter structure will not require additional supports if the distance between two walls located opposite each other does not exceed 4.5 m.
Such attic roofs look original, despite the simplicity of their design. Usually, from the side of the high wall of the attic, quite large window, which allows you to get a well-lit room.
Mansard roof with two slopes
This option is also relatively simple to implement and is therefore widely used. The main thing is that the height of the roof itself allows you to arrange a living space underneath it. The rafter system of this roof looks like a regular gable roof; it can be asymmetrical or symmetrical depending on the location of the ridge.
The gables are usually simple and straight, and the room inside will have the shape of a trapezoid or square (the latter option is only possible if the attic space is spacious enough). The height of the ceilings near the walls should not be more than 1.5 m; above that there is a sloping cone-shaped ceiling.
Main disadvantage gable roof in terms of arranging the attic, this is a loss of most of the free space. That is, the lion's share of the room is cut off by the roof slopes. Of course, this free space is usually used as warehouse, but this aspect affects the size of the attic very significantly.
Broken mansard roofs
In fact, this is also a kind of gable roof, but its slopes seem to have two parts, located at different angles relative to the ceilings. Due to this, you can get a fairly spacious attic floor, which will be equal in area to almost a full second floor (it will be only 15% smaller than the lower floor). The height from ceiling to floor will be the same throughout the attic and will be about 2.2-2.3 m.
Mansard roof broken line - drawing
However, this design involves the construction of a rather complex rafter system. And not every novice master will be able to cope with this task. However, despite this, the option sloping roof quite common.
Hip roofs, mansard roofs
Such a roof implies the creation of the complex type rafter system, requiring the most accurate and painstaking calculations. The surface of the roof itself will have a fairly large area, which is why you will have to spend a lot of money on other materials - insulation, hydro- and vapor barrier films etc. But in general, the attic turns out to be quite spacious, although parts of the usable area are cut off.
But such a roof has maximum resistance to snow and wind loads. The overhangs can be quite large and will be ready to protect the walls of the building from the effects of precipitation. Such attic roofs look very attractive.
Attention! When arranging a hipped roof, it is important to take care of the need to strengthen the layered rafters - they are the ones who experience the maximum load.
Attic roof rafter system
When installing an attic roof, the rafter system can be made from elements of a layered or hanging type. In the first option, the rafters are installed so that they form a triangle with even edges. In this case, the support is carried out on the mauerlat fixed along the perimeter of the walls, on additional supports installed under the rafters, and the connection of two boards in the ridge area also serves as a support point.
When installing hanging type rafters, supports in the form of additional beams are not provided. They rest only on the walls of the house. Pulls may be used. In this case, the rafters themselves work in bending and compression.
Hanging and layered rafters - example drawing
Creating a rafter system when building an attic is a primary task. It is first important to correctly calculate it and take into account all the subtleties of its construction. To understand what will be discussed, you need to familiarize yourself with its main elements.
Table. Main details of the rafter system.
Element | Description |
---|---|
Mauerlat | This is a beam (or board) that is fixed on the upper end of the load-bearing wall of the building. The rafter legs will be attached to it. It plays the role of a support and will transfer the entire load from the roof to the walls of the building. |
Rack | Any vertically located beam that acts as a support for the rafter legs. |
Floors | This is a series of beams laid horizontally to form the floor of the attic floor. They also play the role of the ceiling of the first floor of the building. |
Rigel | These beams are located horizontally and are additional strengthening and supporting elements for rafters. May also be called "puffs". |
Rafters | Also called “rafter legs”. They form the frame of the roof and give it its shape. Moisture-proof materials, sheathing and roofing will be attached to them on top. |
Lathing | Many blocks or sheets of plywood that are attached to the rafters. It is on them that the roofing material will be directly fixed. |
Suspension | A board that helps distribute the load. Installed under the bolt or tightening. |
filly | The board that forms the roof overhang is fixed at the bottom of the rafter leg. |
Prices for construction boards
Construction boards
Required calculations
In order to avoid mistakes when designing an attic, it is important to carry out a series of preliminary calculations. Depending on the chosen type of rafter system and type of roof, they may differ. The easiest way is to use a special program, but you can try to do all the calculations manually.
It is important to determine the area of the final roof, the dimensions of the attic, and the width of the floors. The calculation is made based on the following data:
- length and width of the house;
- volumes of precipitation in winter and summer (this will help determine the required roof slope angle);
- the width of the joints between parts of the floors.
An example of calculating the pitch of rafters in the program "Rafters 1.1"
Let's consider an example calculation: the length of the house is 12 m, the width is 3 m. The amount of precipitation in the area indicates that the required roof slope angle should be about 40 degrees. The calculation is made using the formula Hk = L x tgA, where Hk – required height, L – ½ the width of the building, tgА – tangent of the angle. Total: Nl = 3/2 x tg40 = 1.26. This means that the recommended roof height should be 1.26 m.
Note! Most often, when installing mansard roofs, owners opt for broken rafter systems. The methodology for calculating parameters in this case can be found in SNiP 2.08.01-89 and TKP 45-5.05-146-2009.
In an effort to make the most of any available area in his country house owners sooner or later come to the idea of arranging an attic. Moreover, many dream of coping with this on their own.
But do they know that a do-it-yourself attic roof will actually be reliable and durable only if you follow certain rules and requirements when installing it? It would not be entirely correct to say that the construction of a mansard roof using technology is very different from the construction of other roofs, however, there is still a certain difference. So what is different about the design of a mansard roof?
Types of mansard roofs
A do-it-yourself mansard roof is a great opportunity to expand usable space in a private house. What will be the dimensions of the space enclosed between the gables of the building and the roof slopes depends on the shape and design of the roof.
Mansard roof: photo of a roof with broken slopes
Roof mansard type there are several types:
Single-pitch. This is the simplest option, however, in practice it is used quite rarely, mostly to make attics on small country houses.
Projects of mansard roofs with two slopes
Vary following types gable roofs: gable and broken. The gable gable, perhaps, has no rivals in popularity yet. Neither its design nor its construction by hand, as a rule, does not cause any particular difficulties.
Gable roof attic
The design of a mansard roof with a symmetrical gable system is quite simple. The gables of such houses, often wooden, have a triangular shape. IN load-bearing structure The gable mansard roof includes sloping or hanging rafters.
Note: for buildings up to 6 m wide, the option is considered optimal classic roof with a slope slope of 45 degrees. For wider ones, pointed ones are suitable - with an angle of 60 degrees.Design of a gable mansard roof
A broken mansard roof differs from a gable roof by the presence on each of the slopes of two pitched planes, flat and steep. The slope of the upper one is approximately 20–30 degrees, the lower one is 60–80 degrees. This economical option for a private house, the width of which is no more than 6 m. Making a broken attic roof with your own hands is a little more difficult, but it is fully compensated by the full area of the attic floor, which allows you to equip a bedroom, nursery, kitchen, etc. inside. The frame of an attic roof of this type consists of trusses in which the rafters are reinforced with racks, and the lower chord becomes the basis of the attic floor. The fractured areas are strengthened with stretch marks.
Construction of the attic floor of a sloping and gable roof
Another type of gable is the half-hip. In general, it can be designed as a conventional symmetrical rafter structure supported on a mauerlat, with the only difference being that there are small slopes above its gables.
Hip sloping mansard roof
The design of the hipped roof allows you to arrange an additional floor underneath it - spacious and comfortable. Installation of a mansard roof with four slopes is certainly more difficult than manufacturing gable system. Its rafter system is considered the most complex. The placement of roof windows requires a special approach. IN hip roof they are usually installed in the plane of the roof pie. Beautiful ones provide effective lighting.
Important: There is, however, a certain drawback in this solution. If the windows are not tightly closed during bad weather, the room will flood rainwater.Vertical skylights on a Danish hip roof
More practical in this sense is the Danish version. Unlike the classic hip ones, in their upper part there are pediments that allow you to organize the lighting of the attic using ordinary vertical windows.
Hip roof skeleton with attic
In a conventional hip roof, the rafters are straight, without fractures. The upper end of the corner ribs rests on the ridge, the length of which depends, in particular, on the planned rafter system. Hip roofs are also broken. The implementation of such a design is quite complex, but it allows, in accordance with the plan, a significant increase in the usable space of the attic floor.
The hipped attic is almost hip. Almost, because all her slopes are shaped isosceles triangle, are conjugated at one point, that is hip roof does not have a skate.
Domed roof
The variety of mansard roofs does not end there.
- Multi-pinch ones, which are a combination of several gable ones, have a complex geometry with many kinks.
- Conical, vaulted, domed with exquisite design etc.
All of these options are considered very difficult to implement and initially require professional approach. This is a whole range of tasks, starting from drawing and calculations and ending with coating material, for which you need to find the right decision. The unusualness and special aesthetics of these roofs, as a rule, increases the number of pitched fractures, which form many internal corners(endova). Each of them carries a potential danger to the integrity of the roof. In these areas, as a rule, rainwater is retained and snow bags form, which cause leaks.
Roofs of houses with an attic: photos of the main flooring options
Calculating an attic roof in this case is almost impossible without special skills, so if your dream is to build an attic roof with your own hands, then choose a project with fewer complex elements so as not to face the need for constant repairs.
How to calculate a mansard roof
The design of a mansard roof compared to a conventional one is distinguished by the presence of many additional elements, for example, exits to the roof or roof windows. Quite often, attic projects also include balconies or terraces. All this, naturally, somewhat complicates the rafter system of the structure, and at the same time its calculation.
An attic roof is erected not only during the construction of a house, it can also be a reconstruction non-residential attic into a residential heated room, and then its size and area can be severely limited. All this is taken into account when choosing and calculating the rafter system. In addition to rafters, the supporting system usually includes racks, crossbars, struts, and hangers, and for each of them it is necessary to correctly calculate the cross-section.
Attic roof: attic frame drawings
Calculation of roof area
The next step is to calculate the area of the roof itself. The simplest options are single- and gable roofs. To calculate the area, use elementary formulas from the school geometry course: multiply the length and width of the slope. For a single-slope building this will be the desired value, and for a double-sloping one the resulting values are added up.
Let's take a more complex, broken surface as an example. To calculate the area, it is conditionally divided into separate elementary geometric shapes, calculate the area of each of them and add up the results.
The plan of the attic roof will help to isolate the figures required for the calculation
How to calculate the roof slope without errors
How to build an attic roof so that it is comfortable and warm, but at the same time safe, resistant to various influences, and within a budget that suits your capabilities? When constructing an attic, it is necessary to take into account all the requirements as a whole, since they are, to one degree or another, interrelated. For example,
- with a large angle of inclination, the load on the rafter system is greatly reduced. This is on the one hand, but on the other it is shrinking usable area attics, and material costs increase significantly;
- An excessively small slope increases the climatic loads experienced by the roof, so the calculation is carried out taking into account increased strength. At the same time, the weight of the structure increases, due to which the load on the foundation increases significantly.
The relationship between the angle of inclination and the rafter system
When calculating the angle of inclination, the following factors are taken into account:
- climatic conditions, in particular, the level of precipitation in a given area, maximum wind and snow loads;
- architectural solution;
- design features of the house and attic;
- roofing material.
Formulas for calculating the angle of inclination of a hip roof
To individually calculate the slope, knowledge of the basics of geometry is sufficient. When viewed from the side of the gables, the roof most often has a triangular shape. Having the height and base values, you can easily calculate the length of the side and the size of the adjacent angle. In the calculations, Bradis tables are used, which allow the angle itself to be found by the tangent value.
How to build a mansard roof correctly
So, how to make an attic roof so that the space under it becomes as comfortable and useful as possible? Let’s not focus your attention on the description and calculation of the rafter system and let’s begin step-by-step description assembling the attic roof with the installation of the Mauerlat.
Mauerlat is a timber with square section(100x100 or 150x150 mm), on which the whole roof structure. Moreover, it evenly distributes the load on the foundation and building structures. It must be carefully secured. For example, in brick houses pour a beam from monolithic concrete, into which the mounting pins are mounted, onto which the Mauerlat is mounted.
Mauerlat fixed to the wall
To build a sloping roof for an attic, you first need to get a frame for the walls. This is a structure of vertically installed support posts with horizontal ties. Their height, taking into account the requirements for the attic space, must be at least 2 m. The rafter system will subsequently be assembled onto a frame, so the support posts are installed in accordance with the previously calculated rafter spacing.
Construction of the frame of a sloping mansard roof
The installation procedure is as follows:
- U-shaped racks are installed along the fronts of the building;
- a cord is pulled strictly horizontally between them; if necessary, the racks are adjusted in height;
- with a guide to the cord, install the remaining arches;
- connect them with horizontal jumpers.
Installation of rafters
Installation of rafters begins with those having a maximum angle of inclination.
Installation of side rafters
A groove is cut at the base of the beam, and top part cut at a certain angle. Then each rafter is fastened with a groove to the mauerlat, and with the upper end of the main structure.
Attaching the rafters to the mauerlat
The next stage is the installation of the upper rafters. It is very important here not to disturb the alignment of the structure. To do this, you can make a template from long boards, respectively optimal angle the inclination of these rafters.
Template for upper rafters
Then, according to the template, for convenience, L-shaped structures are first made on the ground, lifted to the roof and firmly fixed to the frame.
Important: for severe truss structure in long attics (more than 7 m), it is better to install a ridge beam through which the loads are evenly distributed.Depending on the chosen coating, continuous or sparse lathing is placed on the rafters.
Attic roofing pie
The technology for constructing a mansard-type roof, as you can see, is not very complicated, however, it will be useful to see how to practically build a mansard roof with your own hands. Video materials also show how to correctly make fastening units.
All more people resort to self-construction Houses.
There are many reasons for this, and everyone is guided by their own motives.
But the main thing is savings, of course, subject to knowledge of the matter.
Building your own home should be a mandatory attribute of success for every man.
Investing your savings in real estate is the best thing to do. The house will last for decades and its value will only increase over time.
Of course, a lot depends on the design of both the internal and external parts of a residential building.
For high-quality construction, you will need to study the technology of constructing a mansard roof. Another important skill is knowledge of carpentry. Or you can study the instructions yourself, which describe in detail the entire project of work. You should also pay attention to the fact that there are different.
When starting construction, you need to ask yourself the following questions::
- What are the best materials to use when building a mansard roof?
- How many stages of work remain to be completed?
- How many people will be needed to help with the construction?
- What kind of attic do you want to build?
It is best to plan the construction of an attic, installing a gable roof with a broken line, so you can get the maximum large area future premises.
Before starting any construction, it should be developed. When working through it, take the numbers indicated in the calculations seriously; even the slightest mistake can lead to future damage to both the roof itself and the walls of the house.
So how to make a mansard roof? This article will help you answer this question.
- For soft roofs, solid;
- Discharged for slate.
Naturally there are certain installation rules soft roof , here they are:
- If the pitched angle of the roof is located in the range from 5 to 10°, then the roof has the appearance of a continuous flooring, special waterproof plywood or boards are used;
- When the inclined roof angle is between 10 and 15°, in this case the roof is made of timber with dimensions of 45×50 millimeters and with a pitch of 45 cm;
- If the inclined angle is greater than 15° for the sheathing timber 45×50 mm is used, but in increments of 600 mm;
- For the skate attachment area install additional beam.
Lathing for soft roofing
Installation of the Mauerlat and rafter system
The Mauerlat is laid after work has been done to level the attic and place the flooring.
Thanks to placement around the perimeter attic space Mauerlat all oblique angles can be corrected.
The material used is timber. The thickness is selected according to the edge of the walls.
When you lay the mauerlat under the side of the cornice, you should be especially careful.
Make sure the structure is non-thrust, because to put additional elements it is forbidden. We will have to dismantle part of the external masonry of the wall and raise inner part walls.
Mauerlat installation
Installation of insulation
It is necessary to insulate the attic space if you are going to inhabit it. First of all, it is worth deciding on the material used as a material. The best solution there will be special basalt slabs.
The insulation density is needed at least 30-40 km per cubic meter , otherwise its subsidence in the future is inevitable. And the thickness is 150 mm. A special film is also installed in the roof to protect it from getting wet.
Step-by-step installation of insulation
Installation of lathing and counter-lattice
After the base has been installed, it is necessary to install to strengthen the structure. This is necessary if the inclined angle is large.
The counter-lattice is installed from small beams, which are placed on top of the main sheathing, already laid on the waterproofing layer. When installing a counter-lattice, a ventilation space is created between the roof and the base, which increases the service life.
Installation of sheathing
Installation of waterproofing and vapor barrier
A do-it-yourself broken roof requires installation of waterproofing. To protect the roof from moisture penetration between the roof and the base a special layer of roofing material or film is laid. The counter-grid helps better ventilation to get rid of the vaporization effect.
The most common vapor control system is three-layer construction- hydrobarrier.
- Reinforced grating. It is woven from polyethylene fibers.
- Anti-condensation or porosity barrier.
Installing waterproofing on rafters or sheathing.
Installation of waterproofing
Types of roofing materials and their installation
The market offers large selection roofing materials for every taste. Each of them has its own advantages and disadvantages. Any builder first of all looks at the cost of the roof, then at its quality and service life.
Roofing material
Conclusion
The construction of an attic roof requires special diligence and painstaking work, if you want to get a high-quality and final result. You will have to invest a lot of effort, not only physical, but also moral.
It will take a smart approach to the work so that it is completed without problems. Encountering a number of obstacles, most owners turn to hired workers for help. But on the other hand, what could bring more pleasure than not doing quality work with your own hands.
Useful video
In this video you will learn how to assemble a mansard roof:
The installation of an attic allows you to expand the useful space of the house. 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. Pediments in in this case 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
The construction of a gable roof is much simpler. But you should understand that the attic in such a design will be small and low ceilings. Therefore, to complete the task it is preferable sloping roof with a slope angle of 40 to 45 degrees. And the smaller the slope, the larger the attic space will be. But in this case, additional strengthening of the structure is necessary, adjacent beams between the rafters.
There are 2 types of rafter 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 load-bearing walls will have to be 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 mansard-type roof 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
Mauerlat in construction is called lower support 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 rafter legs. In other cases, it is placed along the entire perimeter of the walls.
It is necessary to prepare a timber beam coniferous species, 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.
To install an attic roof with your own hands to the base, threaded rods designed for a wide washer are used. 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. You can place a wire rod in the brickwork, 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 horizontal 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 soil subsides. Sliding mount will be useful during construction 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 of the upper rafters, it is 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.
The attic is that room in your home that can carry a wide variety of functional loads: from a workshop and office, to a bedroom and living room. Arranging an attic will cost you much less than a full second floor. And the technology for its construction is more accessible.
In this article we will look at the types of attics, as well as the stages of constructing an attic with your own hands.
The attic is a room limited from below interfloor covering, and on top and sides by roof slopes. Depending on the shape of the attic slopes, there can be:
- single-level symmetrical with gable roof(a,b);
- single-level symmetrical with a sloping roof (c);
- single-level asymmetrical (g);
- two-level asymmetrical (d).
Rafter structures for mansard roofs
If it is not there, or the distance of the wall from the edge of the attic is more than 7 m, hanging rafters are installed. They are composed of the upper part of the roof slope, and are limited at the bottom ceiling beams attics.
Installation of the rafter system is the first stage in the construction of the attic. Therefore, before starting its installation, you should calculate and take into account all the subtleties of this construction. For example, the possibility of arranging an attic floor to replace an existing attic space will depend on the quality of the underlying surface, the type of foundation and its bearing capacity, as well as on the condition of the entire building as a whole.
However, first you need to become familiar with the terminology presented on the construction drawings.
Stages of construction of a rafter frame
First, the top beam is laid, which can have a cross-section of 0.1x0.1 m, or better yet 0.15x0.15 m. It is attached to the racks with special nails, iron staples or self-tapping screws. This block is a rafter frame.
- We install the Mauerlat. It is this element that is the “foundation” of the entire roof. It prevents the roof from tipping over in strong gusty winds, and also transfers the load from the attic to the load-bearing walls of the house. To install the Mauerlat, use: boards (thickness of at least 5 cm) and beams (with a minimum cross-section of 10x15 cm). The beams are laid out around the perimeter of the entire roof and attached to the wall long screws or metal staples (or better yet, both at the same time).
Another method of attaching the Mauerlat to the wall would not be out of place - using thick wire, which is mounted in advance into the top row of the brickwork of the wall. Remember that the stronger you tie the mauerlat and the wall, the stronger the entire attic structure will be. And one more thing: it is necessary to lay a layer of waterproofing under the Mauerlat bars, and treat the boards or bars themselves with an antiseptic and waterproofing impregnation.
- , which are most often purchased ready-made (although you can make them yourself if you wish). Before installing these structural elements, it is necessary to put marks on the Mauerlat that will indicate the location of the leg attachment (the accepted distance between the legs is 15 cm). Applying marks will simplify and speed up this stage.
- We lay the edge rafters to the gable. Special attention attention should be paid to the fact that the edge of the front and the top of the rafters should be in one line. In addition, pay attention to the quality of the board used for the rafters: it should be without any defects (normally no more than 3 flaws per 1 m), thickness - about 4 cm, width - about 15 cm. After the edge rafters are installed, they are connected by a level rope along which all other rafter legs are mounted.
- It's time to unite all the strops together. This is done at the top point of all rafters using a purlin. Then the ridge beam is installed, which, in principle, is not a mandatory element of the frame (it is erected when the roof is longer than 7 m).
- Do not forget that at the stage of erecting the truss structure you need to lay window frames under the attic windows.
- If the roof is below 7 m, then guy wires are installed in the upper part of the rafters, which perform a dual function: they serve as ceiling beams for the future attic and strengthen the frame of the attic roof.
The rafter system is ready. All that remains is to make the lathing, secure the hydrobarrier material, lay a layer insulation material, as well as roofing. The mansard roof is ready. Let's get started internal work, which we will discuss below.
The importance of insulating attic roofs is undeniable, because... walls attic room form unity with the attic roof, or are as close to it as possible. Because of this, the attic room freezes faster in winter and heats up significantly in summer.
Mineral wool is laid in the space between the rafters. In this regard, the base sheets of insulation are cut to fit the size of the gaps between the rafters. Sheets of mineral wool are laid on a pre-laid layer of vapor barrier, and a layer of hydro-vapor barrier is attached on top of the sheets. This multilayer structure creates air gaps, located between the layers of vapor barrier-mineral wool and mineral wool - hydro-vapor barrier. These air channels will subsequently contribute to the ventilation of the entire structure, and therefore they must be opened open in the ridge area. This will improve the quality of insulation.
When insulating an attic, remember that the microclimate of the attic space and the comfort of your stay there will depend on the quality of insulation and the presence of ventilation.