I want to show you right away what will happen if you start installing the roof in the same order that was described in the previous article (see Fig. 1)
Picture 1
We see that one gable will be 6 meters wide, the other 7 meters. In this case, the angles of inclination of the rafters will not be the same, and this will lead to the fact that the ends of the rafters in the eaves will not coincide vertically (bottom figure). In this example, the difference will be almost 10 cm.
In this case, you can go two ways:
1) One skate is made lower than the other. Moreover, such a roof already has three pediments (see Fig. 2):
Figure 2
We will talk about this design in the next article, using only the example of a T-shaped roof.
2) The roof is made with the rafters supported on the floor beams. In this case, skates can be made at the same height. We will now consider this option.
A small digression. In this and the previous articles, I always talk about gables. But instead of gables there can be hips and half-hips. See, for example, Figure 3. Here everyone is free to fantasize.
Figure 3
So, our example:
STEP 1: Install the floor and extension beams. (see Fig. 4):
Figure 4
STEP 2: Install the corner extensions.
To do this, you first need to sew one wind board on the outer corner of the house box to find the corner of the cornice. Then we pull the lace between the outer and inner corners (see Fig. 5):
Figure 5
We do not sew all the wind boards at once, because they will get in the way when marking and installing the rafters of the slopes.
Figure 6
STEP 3: Install the ridge board and rafters (see Fig. 7):
Figure 7
STEP 4: Place the corner rafter on the outer corner of the house frame (see Fig. 8). This operation has also already been described in detail - step 8.
Figure 8
STEP 5: We make and install a corner rafter in the valley. Just as we did in the last article, the halves of the corner rafters will be cut together, but by different amounts, since, let me remind you once again, the angles of inclination of the slopes converging in the valley are different.
So, we tighten the lace in the valley, as shown in Fig. 9:
Figure 9
Using a measuring stick, measure the angle of the bottom cut of the corner rafter??? (see Fig. 10):
Figure 10
Calculate the angle of the upper cut:
? = 90° — ?
We take a small piece of board the size of the rafter and saw one end of it at an angle. We apply it at the top of the valley, as shown in Fig. 11. We mark a line parallel to the ridge board on the right.
Figure 11
We make a gash and again, applying the template, measure the distance shown in Fig. 12:
Figure 12
Using an ax or chainsaw, cut off the upper edge of the right half of the corner rafter to this distance
So, the angle of the bottom cut??? We know that there is a template for the top cut. Now we measure the length of the rafters with a tape measure, make cuts and trim the top edge.
We mark the left half and make it in the same way. The size to which the top edge is cut will differ.
The result is shown in Fig. 13:
Figure 13
Oh, I also forgot to say that the lower end of both halves of the corner rafter will need to be filed down a little. In Figure 14, using the example of the right half, the cut location is shown (in blue):
Figure 14
A hip roof is a roof that has four slopes, two of which (the end ones) have the shape of a triangle. They are called hips and are located from the ridge to the eaves. Two more slopes have the shape of a trapezoid. If the end slopes break off before reaching the eaves, then this design is called a half-hip or Dutch roof.
A hip hip roof is often erected on private houses in a city or village. Thus, the owner has a spacious and comfortable attic, and his house gets an attractive, pretty appearance.
Making a hip roof with your own hands is not as difficult as it might seem at first glance, especially to a person without sufficient knowledge and experience in the field of construction. The process, of course, is not a simple one, but it is quite possible for a person whose hands are growing as they should. There is nothing supernatural here, especially if you use our advice.
Those interested in a hip roof can find videos and instructions on how to build one on the Internet. But without proper markings and planning, it will not be possible to carry out the work. A competent approach will allow you to avoid various troubles and difficulties that often arise directly in the process of work performed.
Before starting construction, you first need to find out all the nuances regarding this roof structure, especially about the rafter systems of hip roofs. In addition, you need to carefully take all the necessary measurements and make the appropriate markings.
Drawings of a hip roof are made using a regular marking strip and the Pythagorean theorem, known to everyone since school days. The main thing in this process is not to rush and do everything thoughtfully.
A correctly completed hip roof project with the correct markings will allow you to independently make all the cuts on the structure that will be required during the construction process.
The main part of the measurements for the construction of a hip roof is made starting from the bottom rib.
Basic rules for constructing a hip roof structure
It must be remembered that the intermediate parts of the rafters are always steeper than the corner parts, therefore the size of the boards and logs used in the manufacture of the rafter system must be at least 50x150 mm.
Unlike a conventional pitched roof, short rafter structural members must be attached not to the ridge board, but to the corner portions of the rafter system. The slope of the intermediate parts of this system must be the same as the slope of its short elements.
During the construction of a hip roof, the same material is used to make the rafter system and ridge board.
The hip roof is erected using an intermediate central type of rafters, which are attached to the two edges of the ridge board.
In addition to the ridge board, the intermediate rafters must also be supported against the upper level of the trim.
When taking measurements, it is better to use a marking strip instead of a regular tape measure. This will make it possible to complete all the markings more efficiently; accordingly, the drawing of the hip roof will be made more accurately than if you used a standard tape measure for measurements.
When taking measurements, it is better to use a marking strip instead of a regular tape measure. This will make it possible to complete all the markings more efficiently; accordingly, the drawing of the hip roof will be made more accurately than if you used a standard tape measure for measurements.
Marking the structure
Porch design with a hip roof: advantages and calculations
In order for the roof of a corner house to be assembled correctly and accurately, you need to apply markings to the Mauerlat and tie-downs. That is, the exact locations of certain skeletal elements. To apply markings, use a construction pencil, a special measuring ruler made of plywood and, of course, a drawing on hand with all the parameters of the frame elements.
- First of all, they mark the central parts of the end walls of the L-shaped house and draw straight lines from them along the long walls of the building. It is along these lines that the ridge run will be located. The lengths of both skates are outlined in accordance with the drawing, as well as the locations of the support posts.
- Now you should mark the locations of the rafter legs. They are mounted with the pitch indicated in the drawing. That is, original marks should be applied to the Mauerlat - the support points of the rafter legs.
Important: corner rafters and regular rafters should be joined using the cutting method. But cuts are made exclusively on the rafters in such a way that they do not exceed a quarter of the cross-section of the lumber. Making cuts on the Mauerlat is strictly prohibited. This will weaken it and the roof, installed by yourself, will become warped over time.
- Lastly, mark the location points of the corner rafters and spigots.
Marking the hip roof
Before erecting a hip roof, you first need to mark it. First, you should mark the center line, which is located at the top level in the frame of the part of the wall that is located at the end of the building.
Next, one end of the marking strip is applied to the previously marked line for the first element of the rafters. To its other end it is necessary to transfer the line of the side internal wall, which will mark the location of the intermediate element of the entire rafter system.
To clarify the exact length of the rafter overhang, it is necessary to move the marking strip to a line that corresponds to the outer contour of this wall. The second end of the batten must be installed on the resulting roof overhang.
After this, we mark the place where the second rafter element of the central intermediate type will be located. To do this, we need to place the rail on the edge of the side wall. On it we mark the exact position of the rafter element, which we planned to place between the upper edge of the frame and the side wall. This is exactly what the hip roof scheme provides.
In the remaining corners of the building, the same sequence of actions must be performed. This will allow us to make accurate and competent markings of all parts of the center of the rafter system, in addition to taking the correct dimensions of the ridge board.
The huge advantage of this marking procedure is that the hip roof, its structure and structure will be designed by us without hypotheses, assumptions and guesses about whether it is necessary to lower the rafter corner elements, since the entire rafter system will be made of a material that has the same width and section.
The design of the hip roof is designed in such a way that due to the use of boards of the same size 150x50 mm throughout the entire system of rafters, it can sometimes happen that the uppermost parts of the rafter elements are slightly higher than the upper parts of the corner elements. As a result, a gap may form between the roofing material and the rafters, allowing for additional air circulation in the attic.
The design of the hip roof is designed in such a way that due to the use of boards of the same size 150x50 mm throughout the entire system of rafters, it can sometimes happen that the uppermost parts of the rafter elements are slightly higher than the upper parts of the corner elements. As a result, a gap may form between the roofing material and the rafters, allowing for additional air circulation in the attic.
Since all parts of the rafter system that are used in the construction of a hip roof are in the shape of right triangles, a more accurate calculation can be made using the Pythagorean theorem, which we already mentioned above.
A rod that is used for measurements
Before you start taking measurements and applying markings, you first need to study in detail all the elements that make up the roof: hip, slopes, and so on. Having studied its structure, it is also necessary to foresee in advance a way to connect the parts of the rafter system to each other.
After we have figured out how the hip roof is constructed, we can begin making the slats that will be used for measurements.
For greater convenience of marking the roof, when the mark is located on the batten at a great distance from the builder’s eyes, the width of this batten should be more than 5 centimeters.
For greater convenience of marking the roof, when the mark is located on the batten at a great distance from the builder’s eyes, the width of this batten should be more than 5 centimeters.
In order to mark the location of the intermediate elements of the rafter system, it is necessary to attach the lath to the mauerlat of the side wall.
It is also necessary to directly measure the thickness of the wall, which will make it possible to make the correct selection for the supporting element of the rafters and roof overhang.
In order not to take all the measurements several times, it is necessary to put on the rail all the dimensions that are used for marking.
In order not to take all the measurements several times, it is necessary to put on the rail all the dimensions that are used for marking.
This will save time, and, unlike measuring with a tape measure, you will avoid errors of several millimeters.
Such seemingly minor errors can result in inconsistencies in the entire rafter system, which will require correction and additional work.
In addition, you need to prepare in advance a complete list of all the coefficients that are used when marking the rafter system. This will allow you to make the roof structure as accurately and correctly as possible.
Such coefficients include such indicators as: the ratio of the length of the rafter elements used to their location, as well as various proportions, characteristics of various slopes and slopes, and so on.
Marking corner elements
Marking the corner elements of the rafter system for hip roofs is carried out in several stages:
- We mark the junction of the marking contour with the upper inner part of the trim; We measure the distance from the intended location to the marking contour, as well as the distance to the nearest intermediate element of the rafters, which will allow us to calculate the horizontal projection. This will help us calculate the rafter length of the corner element of the system; A marking strip will greatly simplify marking work. With its help, the markings of the side walls, which have already been completed, can be transferred to the end walls of the house. In addition to saving time, this will also allow you to maintain precise distances between the central elements of the rafter system.
Useful: for greater convenience of measurements and markings, it is advisable to make a special template, for example, from an unnecessary sheet of plywood that has right angles.
For example, if we have a slope value of 612, the template needs to be marked as follows: at one end of the corner we mark 30 cm, and at the other – 60 cm. After this, by connecting the marks we obtain the required triangle, a sheet of plywood is cut along its contour.
After this, you should attach a beam measuring 50x50 mm to the larger side of the resulting figure. In addition, we mark the slope coefficient of the slopes.
Half hip roof
In some cases, instead of an attic, the owners decide to build a second floor. In such cases, the classic hip roof model will not work, since windows need to be installed on the walls. Therefore, a slightly different design is needed.
The half-hip roof is a conventional gable structure at the top, and a trapezoid at the bottom (between the first and second floors). This roof design gives the entire building a very original and interesting appearance, and also clearly emphasizes the line between floors. This design is most often used for small houses.
The half-hip roof (hatched) has the appearance of a mansard structure with a broken slope. It is often used in cases where the area of the desired room cannot be fit into a triangular shape. The fact is that there is quite a lot of free space under the roof, and it can be used at your discretion. So that the space under the roof does not disappear, it can be used as a living space.
In their design, such roofs are something between a regular hip roof and a regular gable roof.
Where should construction begin? Like the hip roof, this design also requires detailed and accurate calculations. If your knowledge in this area is not deep enough, it is better to order a detailed calculation - half-hip roof + drawing + table from specialists.
After this, in accordance with the obtained indicators, it is necessary to purchase the material. When purchasing, special attention should be paid to the quality of the material. The wood must be dry, without cracks or knots. Before starting work, it is necessary to carefully treat all wooden elements with a protective solution.
The roof must be reliable and strong, so accurate calculations and high-quality execution of all construction work are very important.
The roof must be reliable and strong, so accurate calculations and high-quality execution of all construction work are very important.
Experts do not advise beginners to take on such complex designs, since one minor mistake can lead to unforeseen consequences.
If you really want to build a roof with your own hands, then it’s better to entrust the installation of the rafter system to professionals, and you can do the subsequent installation and insulation of the roof.
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All boxes of houses in the shape of the letter “L” can be divided into two groups:
1 – the width of the base of the gables is the same;
2- the width of the base of the gables is different.
The L-shaped roof, depending on this factor, is built in different sequences.
So let's go in order. In this article we will look at the box of a house with the same width of gables (see Fig. 1). These dimensions are shown in blue in the figure. Our house is made of timber. The floor beams are already installed. The rafters will be hanging, resting on the upper crown of the box (mauerlat).
Picture 1
In principle, the rafter system of an L-shaped roof will consist of two gable roofs crashing into each other. We have already seen how the rafters of a gable roof are calculated, so I will not dwell on this.
STEP 1: Install temporary posts and ridge board. They are located strictly in the middle (see Fig. 2):
Figure 2
Temporary jibs supporting the posts in a vertical position are not shown in the figure. We made the racks from boards 50x150 mm, the ridge - 50x200 mm. The rafters will also be made of 50x200 mm boards.
STEP 2: Install the slope rafters. We mark the rafter template in exactly the same way as was described in the article “Hip roof”.
By the way, I will continue to refer to this article further.
First of all, we install the rafters shown in Fig. 3:
Figure 3
These are rafters on the gables, rafters on the ridge break and rafters in the inner corner of the house box with those opposite them.
How the rafters stand in the inner corner of the house box is also shown in Fig. 4. The indicated dimensions (0.5 m) are the width of the cornice:
Figure 4
Next, we install the remaining rafters in increments no greater than those calculated (see Fig. 5):
Figure 5
STEP 3: Install the corner rafter on the outer corner of the house box. How this is done is described in detail in the article on the hip roof, which I linked to above. There you will also find a description of how the spigots are installed.
STEP 4: Install the corner rafter in the valley (inner corner). It will also consist of two sewn boards with the cross-section of the rafters.
To begin with, let’s fix a small equilateral triangular block in the corner, made, for example, from a 100x100 mm block sawn diagonally (see Fig. 6):
Figure 6
Pull the string between points “A” and “B” (see Fig. 7):
Figure 7
Using a small tool we measure the angle ʺβʺ (see Fig. 8):
Figure 8
We make a template from a small piece of board with the cross-section of the rafters (50x200 mm). First, we file the end at an angle ʺβʺ. Then we apply the resulting blank to the top of the head along the stretched laces and mark the second cut parallel to the ridge board (see Fig. 9):
Figure 9
Using the resulting template, we will mark the upper cuts of the corner rafters. And turning the template “upside down”, we will mark the lower cuts.
In addition to this, we need to determine one more size. Again, apply the template to the top of the head and measure the distance shown in Fig. 10. In this example it turned out to be 3 cm:
Figure 10
This is exactly how much we will need to cut off the upper edges of all the boards from which the corner rafter will be sewn (see Fig. 11).
This can be done either with a regular ax or with a chainsaw.
Figure 11
So, to make the first half of the corner valley rafter, we take a board of the required length and saw down the upper and lower ends using a template. We trim our 3 cm along the entire length of the board. Now all that remains is to make a cut in the place where the rafters rest on the mauerlat. To do this, holding the board parallel to the stretched cord, we make markings (see Fig. 12):
Figure 12
The lace in the figure is shown in blue. We measure the distance we need to lower the rafter so that it aligns with the lace. This distance (5 cm) will be the desired cutting depth. Having done it, we put the rafters in place.
The second half of the corner rafter is done in the same way. It is a mirror image of the first. The result is shown in Fig. 13:
Figure 13
STEP 5: To strengthen the corner rafters, we install racks through trusses (see Fig. 14):
Figure 14
Our springs are made of 100x200 timber, as are the floor beams.
STEP 6: We make and install the spouts (see Fig. 15):
Figure 15
STEP 7: All subsequent steps have already been repeatedly described in previous articles, so I’ll simply list them: we install tie-downs (we also tie together the corner rafters with tie-downs), if necessary, remove the racks under the ridge board (the rafters will be hanging, we talked about this in beginning of the chapter), we sheathe the gables, make sheathing and cornices.
In the next article we will look at how an L-shaped roof is made on a house with different gable widths.
SEE OTHER ARTICLES ON THIS TOPIC:
- Construction of X-shaped (octagonal) roofs.
- Construction of a T-shaped roof of a house.
- Installation of an L-shaped roof with gables of various widths.
- Do-it-yourself hip roof for a house.
- Do-it-yourself half-hip roof.
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Hip L-shaped roof
As you know, not all houses are shaped like a square or rectangle; therefore, L-shaped houses need an L-shaped roof. It is better to invite specialists to take dimensions and draw up drawings of this design, since this model requires certain knowledge and skills.
A hip roof is not too difficult to manufacture, and most importantly, during construction, make all the markings and calculations correctly, using a special rail, as we said earlier, and a table of coefficients.
When thinking about building your own home or even a summer cottage, you want the house to be beautiful, unlike its neighbors, comfortable and functional. It would also be nice if it were inexpensive. A mansard-type roof allows you to solve almost all these problems. The appearance of the house turns out to be interesting, and the building can be decorated in different styles - all the options for combinations of roofing, type and shape of the roof, windows and balconies are probably impossible to count. It’s worth talking about the cost separately.
The combination of slopes directed in different directions gives a very unusual effect. You wouldn't call a house like this ordinary
Angular roof: definition
An L-shaped roof is a structure above a house, which consists of two standard gable roofs connected to each other at right angles. That is, the most complex unit in such a structure is the joints of two gable rafter systems. Namely, their external and internal angles. However, here too it is worth remembering that an angular roof whose gables have the same width is easier to implement. That is, if the end walls of two parts of an L-shaped house also have the same width parameter.
A more complex roof will be one whose gables have different widths. In this case, the height of the ridges of both parts of the roof will be different, and this complicates the joining of the rafter legs of both parts of the structure at an angle to each other. In most cases, such a roof is made broken, where one of its gable parts is located slightly lower than its other gable part.
That is, these types of roofs are used mainly on buildings that have the shape of the letter G.
Important: with correct calculations and installation of the roof, such a rafter system is even more reliable than a simple gable roof. Since the rafter legs of the corner ceiling skeleton themselves serve as a kind of rigid support for the remaining elements.
How much does it cost to build an attic
The construction of an attic floor is considered profitable due to the fact that there is no need to spend money on erecting walls. This is only partly true.
Firstly, a lot of money will be spent on creating a rafter system. Its cost depends on the type of mansard roof chosen (see below) and on the price of lumber in your region.
Secondly, you will have to shell out a considerable amount of money. It is clear that roofing material alone is far from sufficient to ensure the required air conditions for residential premises (if the attic is planned for residential use). It will be necessary to insulate, and the layer of insulation should be significant. For example, for central Russia, the layer of high-density mineral wool should be from 200 mm, plus a layer of waterproofing and vapor barrier.
Thirdly, windows are much more expensive. If you make them auditory, you build a special structure from rafters, which complicates the roof topography, and therefore increases the cost of materials and installation. Even on an ordinary gable roof you have to think about constructing valleys and retaining snow above the windows.
The second option - windows in the roof plane - require particularly careful sealing so that precipitation cannot get inside. This makes installation 1.5-2 times more expensive. The windows themselves cost about the same amount: they must have a reinforced frame and reinforced glass that can withstand snow loads. In addition, for maintenance the frame must be rotary, and this further increases the cost.
There are two types of windows in the attic - vertical and in the plane of the roof. Both types can be used in the same project. The photo below is a good example of such a combination. You can’t really say that the house is unmemorable. How many more options could there be?
Attic roofing in several levels is also a common technique
In addition, such popular and inexpensive roofing coverings - metal-based materials such as corrugated sheets, metal tiles, roofing iron - are not recommended to be used when installing the attic roof of a private house. There are two reasons:
- High thermal conductivity. Due to the fact that metal conducts heat very well, it is necessary to lay a large thickness of thermal insulation materials. Otherwise, the attic will be too hot in the summer and cold in the winter. Increased noise level created by the coating during rain. Even an ordinary roof covered with metal sounds like a drum when it rains. The attic room is much larger in area and the “tool” is more powerful. If you can combat the noise level indoors with additional sound insulation, then you can’t do anything to reduce the sound outside. If the neighbors' houses are located at a considerable distance, this may not be a problem, but if the buildings are dense, conflicts may arise.
If you do the math, additional thermal insulation and sound insulation will minimize the cost savings when purchasing roofing material. Perhaps another, initially more expensive roofing covering will turn out to be more profitable as a result. So here you need to calculate your options.
All this was described so that you have a more complete idea of whether building an attic floor is really that cheap. It turns out - not very good. Nevertheless, this solution has its advantages:
- The attic floor turns out to be light. Therefore, the foundation for private houses will require only a little more powerful than when constructing one floor. Since the cost of the foundation is a significant part of the cost, the gain here is tangible. If there is a shortage of funds, insulating the attic and putting it into operation can be delayed for the required period. Moreover, this delay will be useful. That's why. During construction, wood with high humidity is almost always used. If you start insulation right away, moisture will be absorbed into the insulation. If the “pie” is done correctly, it will go away naturally. But if there are violations, problems may arise. If the roof under the roofing material stands for some time without insulation (but with waterproofing installed under the roofing), then the wood will dry well and there will be fewer problems. The attic allows you to make your house original and non-standard. In any case, the building turns out to be more expressive and individual - there are a lot of design options.
We tried to describe as fully as possible the disadvantages of a mansard roof and its advantages. If the difficulties do not frighten you, choose which design you prefer.
Types of mansard roofs
The attic type roof used in the construction of private houses has various design options. You can make all existing types of roofs, except, perhaps, flat. All others can be implemented both in “pure” form and in combination.
Single-pitch
Houses with pitched mansard roofs look unusual. Its device is the simplest due to the lack of a ridge and the problems associated with its arrangement. The beams rest on a mauerlat mounted on multi-level walls. The bevel is formed due to the difference in height of two opposite walls. In this case, the slope angle should be in the region of 35°-45°. A smaller slope will lead to the accumulation of a large amount of snow, which requires strengthening the load-bearing beams and installing additional supports, and this reduces the already not very large living area in such an attic floor.
If we talk about the external design of the house, the buildings look non-standard. Most often, a large window is made in the high wall of the attic floor: the structure itself is conducive to this. See the photo below for examples.
The construction of a pitched roof is the cheapest if the distance between two opposite walls does not exceed 4.5 meters: you can lay standard-length beams on the walls and not make supporting structures. Apparently this is the reason for the decision in the photographs below, but it turned out very interesting.
If the distance between the walls is smaller, the design is quite simple
Gable
The gable mansard roof is the most widespread: given the general structure, there can be many solutions. The design itself is the most optimal: at relatively low costs it allows you to satisfy various requirements for the required room area.
The easiest way to implement an attic is under a regular gable roof, but its height must be sufficient so that a living space can be allocated under it (if the floor is intended to be residential). May be:
- symmetrical - the ridge is located above the middle of the building; asymmetrical - the skate is offset from the center.
The gables are straight. The room turns out to be trapezoidal; in fairly wide buildings it can be square. The disadvantage of a gable roof of the mansard type is that a large space is cut off on the sides, which is not always acceptable in private houses. To prevent large areas from being wasted, they are used for storage rooms or closets.
With this arrangement, windows are made in the roof; their location depends on the angle of inclination. They can be auditory, as in the photo above, or in the plane of the roof, as in the photo below.
There is another option for installing an attic roof for a private house with two slopes - a one and a half floor. It is installed on walls that have been raised to a certain level. The house is then called “one and a half stories high” (one of these houses is pictured above).
These are two types of gable mansard roofs. There is also a third one - broken ones. They can be separated into a separate category - the device has significant differences.
Broken
The construction of a sloping mansard roof is both more complex and simpler. Essentially these are the same two slopes, but consisting of two parts with different slopes. This structure allows, without spending money on building walls, to get a living space that is only slightly smaller than on the ground floor (by about 15%). In this sense, its structure is simpler. But the rafter system has a more complex structure, and in this sense its structure is more complex.
The design of a sloping mansard roof is the most commonly used version of the rafter system - with part of the rafters being moved beyond the surface of the wall. This creates an overhang that protects the junction with the walls from precipitation.
This type is the most common for self-construction. It easily allows you to increase the usable area, build on small buildings such as a garage, or get additional, almost separate, housing. Since the materials used in construction are usually light, the bearing capacity of the foundation is usually sufficient, but the calculation does not fit. ().
There is a small room made of logs below, and above there is a vast attic supported by racks
Four slopes
These are already complex systems that must be calculated. The surface becomes large, the cost of insulation increases significantly, and at the same time the size of the attic space decreases: parts of the rooms are cut off on all four sides.
Their advantage is their high resistance to strong winds: all surfaces are inclined and the wind load does not put so much pressure on the slopes. The structure is such that the overhangs can be made low, protecting the walls from the effects of precipitation and winds. In addition, many consider houses with such roofs to be the most attractive. The classic version of a hip roof is hip.
One of the types of hipped roofs is a hip roof with an attic space underneath. You can only stand at full height in the central part
When installing them, inclined rafters are reinforced - they account for most of the load. In general, its rafter system is one of the most complex, material-intensive and, therefore, expensive. So that you can evaluate the entire scope of work and costs, consider its design in the photo below.
The top picture shows all the stops and slopes that need to be installed; the second picture shows the structure and location of the rafters more clearly.
There is also a transitional option - half-hip. It is something between a gable and hip roof. In this case, the hip is made only for part of the floor height.
Only the main types of mansard roofs are described. There are also combinations of them. For example, a hip roof can also be a broken one, just like a single-pitched one. There really are a lot of options. The main thing is to avoid gross mistakes when developing a rafter system, and then implement everything correctly.
Mansard roof with balcony
How roof windows are made has already been described above. Balconies are built using almost the same principle. There are even special window systems that allow this to be done in the surface of the slope. Although the implementation is simpler, such a window costs a lot.
If the load-bearing capacity of the walls allows, by increasing the size of the dormer window, you can make a hanging balcony.
The balcony area can be supported by columns. Only in this case the removal is made above the entrance. Then the columns fit organically and also serve as decoration.
A balcony on the pediment of a house with an attic is built according to a different principle. It is protected by an overhang extended forward; if the wall allows, the platform is made hanging.
In small houses, a balcony is often made by moving the pediment of the attic floor away from the load-bearing wall. Due to this indentation, a platform is obtained. Canopies in such roofs are made by extending the roof to at least the same level as the outer wall, and even better - further. This overhang will also protect the gable wall and reduce the amount of rain that will fall on the open area.
The design of this type of roof is such that by extending it you can even create a covered terrace. Its edge can rest on a decorative wall or on pillars.
The difficulty of this project is the long rafters
A similar idea is implemented in this project, but the roof here is multi-gable. It’s difficult to calculate it yourself, and it’s even more difficult to make valleys correctly, which is why they are rare
If we talk about non-standard solutions, then an “L”-shaped mansard roof from two lean-to roofs will turn out to be functional. In addition, this is an inexpensive way to decorate such a non-standard building.
"L" shaped single-pitched mansard roof
When building a private house, bathhouse or utility buildings, the roof truss system requires a special approach. It is important to perform the calculations correctly and prepare high-quality material for installation.
What parameters to choose a roof for the roof of a house
Before choosing roofing material for your roof, you need to familiarize yourself with the technical characteristics of each of them. Among the most significant are the following:
- Wear resistance . This indicator has a direct relationship with the type and quality of the roofing material. For example, the service life of metal tiles is up to 50 years, and ondulin ranges from 15 to 25 years. The question of which roof to choose will not be relevant if the technology for its installation is not followed.
- Roof type features . The choice of roofing material for the roof depends on the design features of the structure. For example, for a flat roof it is recommended to use metal tiles. As for the question of which roofing materials are better suited for a roof with 3 or 4 slopes, the answer will be clear - flexible or bitumen tiles.
- Purpose of the building . The choice of types of roofing for private houses also depends on the type and purpose of the building. Metal tiles, soft roofing or composite tiles are ideal for covering private houses, bathhouses or country houses. As for outbuildings, it is better to use inexpensive materials such as ondulin.
- Roof weight . Different types of roofing for the roofs of private houses and outbuildings differ not only in their characteristics, but also in weight. This affects the overall weight of the roof. When choosing a roofing material, you should consider what material will be used to construct the walls of the building. For example, for the roof of a wooden house it is recommended to use a material with low weight.
Before making the final choice, experienced craftsmen advise comparing roofing materials according to all parameters and characteristics.
Design of truss structure
The calculation of load-bearing structures in construction is usually performed using the limit states method, i.e. at the moment of loss of resistance of the structure under the influence of external loads up to destruction or unacceptable damage.
The rafter system reaches its limit state if:
- the strength of the structure is completely exhausted and it collapses; Deflections of the elements of the supporting frame provoke unacceptable violations in the nodes of the rafter system, and further operation of the roof is impossible without repairs.
According to building codes, the maximum permissible deflection of a rafter leg or tie is 1/200 of the length of the element. To ensure high reliability of the structure, it is recommended to design the roof taking into account the maximum permissible deflection of 1/250 of the rafter length.
The calculation of the roof truss structure is carried out taking into account the maximum loads from:
- own weight; wind pressure; snow weight; the weight of people servicing or repairing the roof (the load from a person is usually taken as 80 kgf/sq.m).
To obtain information on the basis of which calculations are made, it is necessary to have:
- SNiP for roofing structures; table for calculating the cross section of the rafter leg; table of cross-sections of rafters; climate map of the region (determination of wind and snow load).
The cross-section of the timber from which the elements of the rafter structure are made is calculated using a special formula, which takes into account the length of the rafter leg, the pitch between the rafters, and the resistance of the selected type of wood to external loads.
Tables for selecting sections of elements are used when designing simple roofing structures. Developing a roof project of complex shapes requires a professional approach.
Calculations
To make an L-shaped roof with your own hands, you must first make accurate calculations. In particular, the load on the rafter system is calculated. Moreover, three parameters are taken:
- Constant load. This refers to the weight of the entire roofing pie, which will put pressure on the roof skeleton (insulation, hydro- and vapor barrier, finishing roofing material).
- Seasonal load. This includes precipitation in the form of rain, snow and wind. Moreover, based on the prevailing climatic characteristics of the region, it is advisable to select the roof slope angle. This will reduce the seasonal load on the roof. So, if snow and rain predominate in the region, then it is better to make a roof with a large slope angle. If winds prevail in the region, then it is better to make a flatter roof for a house in a city or countryside. This will reduce its windage and, accordingly, the wind load.
- Additional load. Here additional communication devices are taken into account, such as a water tank located under the roof, a satellite dish, etc.
Important: all calculations for an L-shaped roof should only be carried out by a specialist. In accordance with the received data on all types of roof loads, he will draw a drawing that will indicate the slope angle of the hip roof slopes in the form of an L and display all the parameters of the elements of the rafter system.
Knots of the rafter system
The reliability of the truss structure is influenced by the following factors:
- correct choice of rafter system configuration; strength of connections in structural units; accuracy of engineering calculations when designing a roof; correct choice and quality of materials; installation quality.
The type of rafter system and the presence of certain element nodes is dictated by:
- designed roof shape; dimensions of the overlapped space; the presence and location of internal supports or load-bearing walls.
When building houses with a usable attic or attic floor, truss structures with layered rafters are usually used. Their main nodes include:
- support unit for rafter legs; ridge knot; “rafter-strut-post” assembly; “beam-post strut” assembly, etc.
When designing, it is important to immediately decide on the methods of fastening the elements. The choice depends on some of the characteristics of the lumber, as well as the preferences of the people conducting construction work.
Key stages of roof construction
Installation work begins after the preparation of the project, which indicates all the dimensions of the elements and their relative positions, as well as the principles of connection. In addition, you should purchase and bring the necessary building materials, tools, fasteners, etc.
The principles of constructing a pitched roof, in general, do not depend on its configuration. The work technology includes the following stages:
Before starting independent work, it is recommended to familiarize yourself with the thematic video.
Installation of L-shaped roof
If you do not know how to make a corner roof, then after reading the detailed instructions below, you will be able to build such a roof yourself. So, a roof curved in the shape of an L is mounted with your own hands in the following order:
- Support stands are installed on wooden purlins in accordance with the applied markings. They are additionally fixed with staples, metal corners and strengthened with braces.
- A ridge beam is placed on the racks and fixed. Particular attention should be paid to joining the two ends at an angle of 90 degrees. Here the fixation needs to be made more rigid so that the roof built with your own hands is reliable.
- Now it is necessary to assemble two rafters into a single truss and install them on the mauerlat on the pediment of one of the parts of the house. It is important to remember that the rafter legs must have a cornice overhang of at least 50 cm. The same truss is installed on the second gable of an L-shaped house.
- According to the resulting pattern, the remaining trusses are mounted at a given pitch until we reach the corner where the two parts of the roof meet.
- Here we install an outer corner rafter, which is securely fixed at the intersection of the ridges at the top and the corners of the mauerlat at the bottom.
- After this, the corner rafter is installed internally (valley). Since here the roof has a negative angle, you need to be very careful with how securely you fix your leg. In order to make the correct cut, it is necessary to install a timber pattern from the ridge to the mauerlat and using a small tool (measuring tool) we measure the angle ʺβʺ, that is, the angle of the cut in the beam. We first form it on a pattern block, and then transfer it to the main beam for the corner rafter. We securely fix the resulting element.
- And finally, we install the rafts - short rafters. They are cut out in advance in accordance with the parameters in the drawing. That is, each flange will be shorter, the closer to the upper end of the inner corner rafter it is located. On the outer corner rafter, on the contrary, the flange will be shorter towards the lower end of the leg.
For reliability, the entire structure is reinforced with braces and wind beams. The sheathing is sewn on top of the rafter system, and only then all the layers of the roofing cake are laid. As can be seen from the instructions, constructing a variation of this corner roof is, in principle, not difficult. The main thing is to strictly observe all the parameters of the frame elements.
Balancing the heating system in a private house, how to distribute heat
Flat roof slope calculation and materials
Features of a roof with a valley
The construction of a roof truss system of complex shape (multi-gable roofs) requires the creation of connections for ridges and slopes. The planes of the slopes can have different geometric shapes: triangle, rectangle, trapezoid. The endova is the junction of the slopes with the formation of a negative angle.
In the house plan, roofs with valleys look cruciform, T-shaped or L-shaped. These are the two main ways to create roof junctions. At the design stage, a roof plan (top view) is drawn up, taking into account attic and dormer windows, all junctions, roofs over terraces or verandas, indicating all linear dimensions. The general plan of the roof is divided into rectangles and squares; the main rooms and extensions are indicated on it.
On the roof plan, the main purlins should be indicated, and in the perpendicular direction, the secondary purlins over smaller rooms should be indicated. Then lines are drawn connecting the corners of the roof above the secondary rooms with the corners of the main roof. These diagonal lines indicate the location of the valleys - the internal corners formed by the junction of the slopes.
When installing a rafter system, the valleys at the joints of roofs of the same height (i.e. if the ridge girders are located at the same level) are diagonal rafters, resting with the upper end on the ridge girder, and with the lower end on the mauerlat. The installation of such rafter legs is carried out similarly to the installation of diagonal rafters for a hip roof.
Depending on the size of the extensions, the angles of the roof slopes can have different values. The geometry of the roof can be changed by shortening the size of the purlins. The angle of inclination of the valley changes accordingly. The roof truss system with a valley can be made using a spacer or non-spacer method. If spacer rafters are installed, then to relieve excess stress, a horizontal tie should be secured at the bottom of the structure.
Installation of the valley
The design and installation of a roof with valleys is quite complex. In this case, mistakes can lead to roof collapse or leaks. One of the purposes of the valley is to ensure the removal of precipitation. Valleys differ in their design:
- open; closed; intertwined.
To install a valley on mating slopes, it is necessary to install a continuous sheathing. Waterproofing is laid along a wooden gutter - it is better to lay it in two layers. Then the valley is secured with self-tapping screws. If its joints are horizontal, the overlap should be at least 100 mm (recommended value is 300 mm). If the valley is mounted on a slope with a slight angle of inclination, it is recommended to add another layer of waterproofing, and when installing the valley on a metal tile roof, additionally use a self-expanding sealant.
An open-type valley is easier to install and removes precipitation better. Closed and interlocking structures are typically used on steeply pitched roofs covered with certain roofing materials. Their disadvantages include increased costs for additional waterproofing and some installation difficulties. Intertwined and closed valleys drain precipitation worse, and in cold climates in winter they serve as a place for accumulation and compaction of snow.
Video instructions will help you understand the intricacies of constructing rafter and roof structures of the most popular types.
Author Pavlov Yuri Nikolaevich
Step-by-step instructions for performing the work
The sequence of stages of roof construction is as follows:
- taking measurements of the building box (dimensions may slightly differ from the design ones);
- preparation of materials and tools, treatment of wood with antiseptic;
- fastening the Mauerlat to the wall;
- installation of a ridge crossbar, if needed (for layered rafters);
- frame installation;
- strengthening the roof using racks, struts and tie-downs;
- waterproofing;
- sheathing;
- providing ventilation;
- installation of drips;
- installation of coating.
Fastening the Mauerlat
In order for the roof to be securely fastened, you need to ensure that it is securely connected to the wall of the building. If a wooden house is being built, then the Mauerlat is not required - this element is the upper crown made of timber or logs. In this case, fastening to the wall is carried out using special “floating” fasteners. They are sold ready-made, most often called sleds. This type of roof arrangement allows the entire structure to shift slightly as the walls shrink without destruction or deformation.
“Sliding” fastening in a wooden house
A similar situation arises with a frame house. In this case, the Mauerlat will be the top frame of the walls. It is attached to the frame posts with a gash using angles, staples or nails.
Methods of attaching rafters to the frame in a frame house
The roof structure made of brick, concrete blocks or concrete involves fastening through a Mauerlat. In this case, there are several ways.
There are four ways to place the Mauerlat on the wall:
- on staples;
- on stiletto heels;
- on anchor bolts.
The Mauerlat can be secured to brackets. In this case, wooden blocks are placed into the masonry from the inside. They should be located at a distance of 4 rows from the edge. One side of the bracket is attached to the mauerlat, and the other to the same block in the masonry. The method can also be considered simple. It is not recommended for large buildings with high loads.
Fastening the Mauerlat to brackets. Antiseptic wooden blocks are provided in the masonry of the wall with a pitch of 1-1.5 m
When installing the roof yourself, fastening can be done through studs or anchor bolts with a diameter of 10-12 mm. The fasteners are laid in the masonry. The Mauerlat is temporarily placed on the sawn-off edge and lightly hit with a hammer. After this, indentations remain on the beam at the fastening points. You need to make holes for the studs along them. After this, the beam is put on the fasteners and the nuts are tightened. The method is ideal for walls made of lightweight concrete with a monolithic reinforced belt.
Attaching the Mauerlat to studs
Attaching the rafters to the mauerlat
In houses made of brick or stone, it is more reasonable to perform it using rigid fastening of the rafters to the mauerlat. In this case, you can use both a layered and hanging system. The design involves two methods:
- with notch;
- without cutting.
Connection with and without
cutting In the first case, the rafters are cut with a slope so that they fit tightly to the mauerlat. To remove the cornice, fillies are provided. They are attached to the leg with an overlap of at least 1 m. Rigid fixation of the assembly should be done using self-tapping screws, nails or staples. But the assembled frame will be more reliable if metal corners with holes for self-tapping screws are used for fixation.
The method without cutting often does not involve the use of fillies. In this case, the beams themselves provide the frame extension. This option is simpler than the previous one, since it does not require high precision. It is suitable for beginners. In this case, stop bars or boards are used to ensure a tight fit to the Mauerlat. Rigid fixation, as in the previous case, is performed with metal corners on both sides.
Attaching rafters to the wall
The completed frame must be secured to the frame of the building - this will prevent a strong gust of wind from tearing off the roof. To do this, the rule is to use a twist of two wires with a diameter of 4 mm. They are wrapped around the leg where it rests on the mauerlat, and then the wire is attached to the wall with an anchor or ruff about 4-5 rows before the cut. The element must be laid in the masonry in advance.
Wind protection
For a wooden house, you can simplify the task. You can assemble the frame using staples. This option will speed up the process. But it is important to remember that this method is only suitable if the walls are made of wood.
Strengthening the system
How to strengthen the frame for spans of more than 6 meters? It is necessary to reduce the free span of the rafters. For this purpose, struts and racks are used. Reinforcement must be done taking into account the layout; it is important that these elements do not interfere with people’s stay and fit harmoniously into the interior.
The struts are usually placed at an angle of 45 or 60 degrees to the horizontal plane. The racks cannot be supported on the floor span. They can be installed on underlying walls or beams and trusses thrown between walls.
Tightening is necessary to reduce the thrust. Because of it, the rafters can simply move apart. This is especially true for systems with hanging beams. To assemble the frame, use two ties, which are attached on both sides of the rafters. Fixation is carried out using screws, nails or studs.
Connection to purlin
At the top point, the rafters rest on an intermediate or ridge girder. Depending on the chosen system, location and width of the span, it is made of timber with a cross-section from 50x100 to 100x200 mm. Fastening is carried out on connecting metal plates, bolts or nails.
Lathing
Before starting work at this stage, it is necessary to lay waterproofing material. Builders recommend using a vapor diffusion moisture-proof membrane. It costs more than plastic film, but provides more reliable protection. Owning your own home is not a reason to save money.
Roof structure under corrugated sheets
The roof requires fastening of the sheathing. The type depends on the selected roofing material. For metal, a sparse sheathing of boards 32-40 mm thick will be sufficient. Under bitumen shingles you need a continuous sheathing made of 25-32 mm boards or moisture-resistant plywood.
Ventilation of the under-roof space
Before proceeding with the roofing stage, it is worth considering the ventilation of the under-roof space. This will protect structures from mold, mildew and destruction.
Proper ventilation under the roof will protect the structure from the appearance of fungus
For ventilation it is necessary to provide:
- air flow through the cornice (the cornice is hemmed with a sparse board or special perforated soffits);
- air movement under the covering (there should be a gap of 2-3 cm between the insulation and the roof);
- air outlet in the area of the ridge (for this, a ridge and/or point aerator is installed on the roof).
Roof covering
The type of roof is selected for aesthetic and economic reasons. It is also worth studying the manufacturers’ proposals and finding out the permissible slope. For example, it is not recommended to lay bitumen shingles on a slope of more than 45°.
Seam roofing is a lightweight fireproof and durable covering
The flooring material must provide reliable waterproofing. Its installation is carried out in strict accordance with the manufacturer's instructions. There are five most common types of coverage:
- seam roofing;
- metal tiles;
- corrugated sheeting;
- ondulin;
- flexible tiles.
