Tree – optimum material for the device of system slung in construction of roofs. Wood is convenient in work. Modern tools and ways of processing of wood allow to connect reliably among themselves various structural components of rafter system. One of types of similar constructive decisions is lengthening of rafters. It is possible to make it independently.
1. On construction site quite often there is need for rafters, big longwise, than the available standard preparations 4 m long. Length of rafters can be increased in various ways. For example, it is possible to add part of bar of the necessary length and on the basic rafter element to fix it with an overlap. The blousing should not be less than one meter. At fastening implementation the nails need to be hammered in chessboard order. It is also possible to use through pins with washers and nuts on both sides.
2. It is possible to extend rafters in the way which is a little more difficult previous: to execute butt joint. For this purpose cut off at right angle faces of rafters which should be connected. It is very important as the condition of elements and their resistance to deflections under the influence of loading will depend on contact of faces. To record connection, fill from two parties of pad from bar. Now instead of wooden pads apply also metal plates which make at the plant by stamping by teeths. They are reliably fastened with two connected elements that stiffens joint and additional durability.
3. Are attached to wall of rafter on the top wreath of wall or by means of inferior purlin. That such connection was reliable, it is necessary to make cuttings, both on rafter, and on inferior purlin. The joint has to not just allow elements to adjoin, but also to provide point of support of rafters on wall. Such joints fix by means of plates, metal brackets, bolts, nails and pins.
4. Fixing slung to ridge board, it is necessary to adjust the joined surfaces very precisely and to fix by nails. That the roof did not sink in places of building of rafters, establishing each extended element, place places of joints alternately below and at the top of slope.