Do-it-yourself hip roof is not such a difficult job as it might seem to a person who does not have sufficient experience and knowledge in construction.
The work, of course, is not the easiest, but quite doable, there is nothing supernatural in it.
For those who are interested in a hip roof, videos and instructions for its construction can be found on the Internet, but the main thing is still the correct competent marking and layout, which allows you to avoid various difficulties and troubles directly in the process of work.
Before starting construction, you should find out all the details regarding this type of roof, and precisely the truss system of hip roofs, as well as carefully perform all measurements and mark everything in detail.
The difference between hip roofs is that their design is a combination of two elements from which the roof is built:
- The first element is two ordinary slopes, which can be found on any other roofs.
- The second element gives the hip roofs their uniqueness: since the slopes do not cover the entire area of the house in length, the remaining space is closed with the help of two side hips, which give the name to the whole structure.
Hip roof drawings are drawn up using the usual marking rail and the Pythagorean theorem, familiar from school, the main thing is not to rush and do them carefully and deliberately.
A properly prepared hip roof project with competent markings also allows you to independently make all the cuts on the rafter structures required during the construction process.
The technology for erecting hip roofs is considered the most correct, and the main part of the measurements in it is made starting from the lower edge of the rafter system, as with installation of pitched roof rafters.
Basic rules for the construction of a hip roof:
- It should be remembered that the intermediate elements of the rafters are always steeper than the corner elements, therefore the size of the boards or logs used in the manufacture of the rafter system must be at least 50x150 mm.
- The short structural elements of the rafters should not be fastened to the ridge board, as in a conventional pitched roof, but to the corner elements of the rafter system, while the slope of the intermediate elements of this system must coincide with the slope of its short elements.
- The construction of a hip roof implies that the same material is used to make the ridge board and the rafter system.
- Since the roof is hip, during its construction an intermediate central type of rafters is used, the fastening of which is carried out along both edges of the ridge board.
- Intermediate rafters rest not only on the ridge board, but also on the upper level of the strapping used.
Useful advice: when taking measurements, it is recommended to use a marking rail instead of a regular tape measure, which will allow you to mark up better and, accordingly, make the drawing of the hip roof more accurate than when using a standard tape measure for measurements.
Hip roof markings
Before you build a hip roof, you should mark it. First of all, it is necessary to mark the center line located at the upper level of the strapping of the part of the wall located at the end of the building.
After that, an accurate measurement of the half thickness of the ridge board is made, as well as marking the location of the first element of the truss system of the central intermediate type.
Next, one end of the marking rail is applied to the line marked earlier for the first element of the rafters, and a line is transferred to its other end, the side of the inner wall, marking the location of the intermediate element of the truss system.
The exact length of the overhang of the rafters is specified by transferring the marking rail to the line corresponding to the outer contour of the same wall, while the second end of the rail is installed on the formed roof overhang.
Next, the location of the second element of the rafters of the central intermediate type is marked, for this the rail is located on the edge of the side wall and it marks the exact location of the rafter element that is planned to be located between the upper end of the strapping and the side wall, as the hip roof scheme provides.
In the remaining corners of the building, the same sequence of actions should be performed, which allows you to accurately and correctly mark all the elements of the central part of the rafter system, as well as the dimensions of the ridge board.
The undoubted advantage of such a marking procedure is that the hip roof - structure and device - will be designed without hypotheses and assumptions about whether to lower the rafter corner elements, since the entire rafter system will be made of material with the same width and section.
Important: the design of the hip roof due to the use of identical boards 150x50 mm in size throughout the rafter system can turn out to be such that the upper parts of the rafter elements are slightly higher than the upper parts of the corner elements.As a result, a gap is formed between the roofing material and the rafters, in which additional air circulation is performed in the attic room.
Since all elements of the truss system on which the hip roof is built are rectangular triangles in shape, their more accurate calculation can be made using the Pythagorean theorem, which was already mentioned above.
Rail used for measurements
Before you start measuring and marking, you should carefully examine all the elements that make up the roof - hip, slopes, etc. Having dealt with its device, you should also think in advance how to connect the elements of the rafter system to each other.
Having figured out how the hip roofs are arranged, you can begin the procedure for manufacturing a rail, with which measurements will be taken.
In order for the marking of the roof to be more convenient when the mark located on the rail is located at a great distance from the eyes of the worker, the width of this rail should be about 5 centimeters.
The location of the intermediate element of the truss system is marked by applying the rail to the Mauerlat of the side wall.
You should also measure the thickness of the wall itself, which will allow you to make the correct selection for the supporting part of the rafters, as well as the roof overhang.
Important: In order not to take all the measurements several times, it is enough to put on the rail itself all the dimensions used for marking.This saves time and avoids errors of a few millimeters, which can be made, for example, when using a tape measure to re-measure each section. As a result, such errors can lead to inconsistencies in the entire rafter system, which will require additional work to correct them.
In addition, you should prepare in advance a list of all the coefficients used when marking the truss system in order to make the roof structure as correctly and accurately as possible.
These coefficients include such as the ratio between the length of the used elements of the rafters and their location, as well as various proportions, characteristics of various slopes and slopes, etc.
Intermediate rafter length
The list of coefficients is divided into two columns, one of which indicates the coefficients used to mark the intermediate elements of the rafters, and the other - the values \u200b\u200bused for the corner elements of the truss structure.
An example of such a table is shown in the figure.
For example, the calculation of the required leg length of a rafter element is made by multiplying the appropriate coefficient by the laying of a given leg.
Important: this table of coefficients is necessary during the construction of a hip roof, since calculating the rafter length without using it can take quite a long time, and even turn out to be incorrect as a result.
At the moment, in construction, there are a number of methods for calculating the rafter length, and all of them are based on the transformation of a horizontal projection into the length of the rafter, which is again performed using the Pythagorean theorem.
A table of coefficients prepared in advance allows you to significantly speed up and simplify all calculations, in addition, they are obtained much more accurately, as with building a slate roof.
Sample hip roof calculation
Using a marking rail, the horizontal projection of the intermediate rafter element is measured.
Next, they find in the table of coefficients the value corresponding to the selected roof slope, the obtained values are multiplied among themselves, resulting in the values of the length of the element of the truss system.
Next, the rafter length of the lower edge is measured.
Useful: the rafter length is the total distance between the sample on the ridge board and the sample used to fix the supporting part of the rafter leg.
The length of the rafter overhang is calculated by multiplying its horizontal projection by the coefficient obtained from the table. Another way to calculate the rafter length is to apply the Pythagorean theorem: a2+b2=c2, where a is the vertical projection of the rafter element, b is its horizontal projection.
The resulting value c will be the desired rafter length. The theorem is usually applied when making non-standard hip roofs, when the required coefficients are not in the table.
Layout of corner elements
The marking of the corner elements of the rafter system for hip roofs is carried out in several stages:
- The junction of the marking contour with the inner upper part of the harness is marked;
- The distance from the marked point to the marking contour is measured, as well as to the nearest intermediate element of the rafters, which allows you to calculate the horizontal projection used to calculate the rafter length of the corner element of the system;
- The marking rail allows you to simplify the marking work, with the help of which the already completed marking of the side walls is transferred to the end walls of the house. This also allows you to maintain the correct distances between the center elements of the truss system.
If we consider the hip roof project on the house plan, we can make sure that the distance between the selection of the reference plane of the corner rafters to the marking contour of the short elements of the truss system is a horizontal projection of the short element.
Useful: for the greatest convenience of marking, you can make a special template, for example, from an unused plywood sheet with right angles. For example, with a slope value of 612, the template is marked as follows: 30 cm is marked on one part of the corner, and 60 cm on the other, after which, by connecting the marks, the required triangle is obtained, along the contour of which the plywood sheet is cut. A beam measuring 50x50 mm is attached to the larger side of the resulting figure, in addition, the slope coefficient of the slopes is marked on it.
The hip roof is not as difficult to manufacture as it seems, and the most important thing in its construction is to correctly make all calculations and markings using a special rail and a table of coefficients used.
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