Mechanical tiles are easy to install and relatively economical. But the site remains large, within the framework of a house. Take the time to properly prepare your site. The specialists like Minnesota Tile Contractors will provide you with valuable advice on choosing the right model according to the characteristics of your site, its location, your budget and your skill level. A good preparation will save you considerable time, avoiding trial and error during installation.
The layout consists in carrying out a preliminary study of the roof plan, according to the model of tile to be used and its dimensions (length and width). This makes it possible to know the number of elements required, but also to avoid the cutting of the tiles on the edge, on the sides of the slope of the roof or at its top. Adaptations can be considered, either by changing the model, or by modifying the frame plan, the sewer overhang of the rafters for example. Note that in practice, these are generally installed while preserving a certain margin in the lower part, which makes it possible to adjust the location of the battens. They are not cut until after the tiles have been laid.
The layout also makes it possible to estimate the number of special pieces needed (edges, ridge caps, half-tiles for cross-jointed installation, ventilation sleeves, etc.).
Knowing the gauge is essential for the layout. It corresponds to the part of the visible tile which is not covered by the top row. It is also the measure to remember to adjust the spacing between the battens. As a rule, it is indicated for each type of tile. Some are of variable gauge, which makes it possible to adapt the spacing between the battens, and to avoid the possible recutting of the last row.
The roof underlayment is fixed stretched over the rafters. The battens are not fixed directly above, but on a 2 cm thick counter-batten, which allows air circulation between the top of the screen and the underside of the tiles.
Laying the battens
As a rule, the battens are made of wood. Their section, square or rectangular, depends on the load of the roofing and the spacing of the rafters. The load, expressed in decaNewton per square meter (very approximately 1 kg), corresponds to that of the roof itself plus those of normal climatic conditions. For example, for a load of 150 daN / m2 and a center distance between rafters of 60 cm, battens with a section of 25 x 50 mm are needed. The battens are nailed to each rafter (or to the counterlath). They can be stapled, if they do not exceed 25 mm in thickness.
Mechanical tiles (interlocking or sliding with relief) are installed either with straight joints or with crossed joints, some models however allowing the two installation methods to be used interchangeably. They have a small tenon on their internal face which allows them to be suspended on the battens.
The installation begins at the bottom of the slope, to the right or to the left according to the direction of the lateral interlocking, so that each tile comes to overlap the one previously laid. The tiles of the first row laid, those of the second are placed on top, and hung on the battens of the next row. If the layout and the bedding have been correctly carried out, they fit perfectly on those of the first row. In the case of installation with crossed joints, one uses half-tiles posed at the end, one row out of two.
The installation is generally carried out diagonally and not row by row, in order to limit movements on the roof. The tiles are not always nailed down. It depends on the area of exposure to the wind (defined according to the NV65 rules) and the degree of the slope. In the majority of cases, moreover, they are not nailed down, or only at the rate of one in five. On the other hand, in the event of a steep slope (greater than 175%), they will all be nailed down.
At the top, the ridge line, between the two slopes, is covered by tiles with special interlocking, laid in the opposite direction of the prevailing rain winds. These tiles are fixed by spikes, lag bolts, special hooks. Each passage of conduit is the subject of a particular installation below, on the sides, and above the obstacle, in order to guarantee the tightness and to channel the runoff water. Roof windows, skylights, hip rims, valleys, etc. are also subject to special treatment.