Photovoltaic systems are most often installed on pitched roofs. Depending on the roofing, the appropriate type of fasteners is chosen for the installation. The most commonly used connecting elements include: adjustable mounting brackets (trapezoidal metal sheet), hooks (ceramic tile), double-threaded screws (metal tile), L-type mounting brackets (roofing felt), and mounting brackets without regulation (plain tile), which are presented on Fig. 1.

Figure 1: Examples of elements for connecting the roof with the support structure for the PV system: a) adjustable mounting brackets (trapezoidal metal sheet), b) hook (ceramic tile), c) double-threaded bolt (tile sheet), d) L-type mounting bracket (roofing felt), and e) non-adjustable mounting bracket (plain tile) – KENO Sp. z o.o. mounting elements. Photo used by permission of KENO Sp. z o.o..

Installation of photovoltaic modules on a pitched roof is presented in the subsection using the example of a roof covered with ceramic tiles. The installation consists of the following steps.

• In the first step, the tile is lifted and slid under the higher row to expose the rafters, as shown in Fig. 2.

Figure 2: Exposure of rafters by sliding roof tiles – installation systems by KENO Sp. z o.o. Photo used by permission of KENO Sp. z o.o..

• The second step is to screw the mounting hook to the rafters. The spacing of the brackets depends on the dimensions of the modules. In the case of corrugated roof tiles, the mounting hooks should be hung on the roof tile, so that the support part lies in its hollow. In the case of installation of photovoltaic modules on the roof where the rafter spacing is larger than the width of the module, the roof truss has to be extended by means of reinforcement between two rafters, to which the mounting hooks can be screwed. The reinforcement is made of battens screwed to two fixing angles, which are in turn screwed to the rafters. The method of screwing the mounting hook to the rafters is shown in Fig. 3.

Figure 3: Screwing the mounting hook to the rafter – KENO Sp. z o.o. mounting systems. Photo used by permission of KENO Sp. z o.o..

• The third step is to cut the tiles in such a way that the protruding hook does not catch on the tiles and to fix the tiles in their original place ( Fig. 4 ).

Figure 4: Tile hook installation – KENO Sp. z o.o. installation systems. Photo used by permission of KENO Sp. z o.o..

• In the fourth step, the rail profiles are screwed to the hooks. The profiles should be placed between \( \frac{1}{8} \) and \( \frac{1}{4} \) of the module height in order to evenly distribute the forces acting on the module when they are loaded, e.g. during rain, snow and wind.

• In the fifth step, the positioning of the clamps on the profiles is performed and they are screwed to the sliding grooves with Allen screws, as shown in Fig. 5. Place the appropriate number of sliding grooves in the profile at intervals equal to the width of the photovoltaic panels or their length depending on the orientation of the module installation.

Figure 5: Mounted ties for profile grooves – installation systems of KENO Sp. z o.o. Photo used with permission of KENO Sp. z o.o..

• The final step is to mount the photovoltaic modules to the profiles using clamps ( Fig. 6 ). During installation it is important to keep a space between the modules and the roof sheathing to allow air circulation.

Figure 6: Mounting of PV modules on the roof with clamps – KENO Sp. z o.o. mounting systems. Photo used by permission of KENO Sp. z o.o..