Always check your fill before starting. Look for crocked eaves, out of square gables, out of parallel ridges or eaves and sagging rafters or ridges. The first batten should be installed with the top corner flushed with the fascia. The second batten is the most important and is installed by chalking a straight line 15 inches from the first batten. As the roof slope increases this dimension should be reduced accordingly. This will allow the front lip of the panel to overhang the fascia. When the eave is crocked, adjust the line down slightly to average this discrepancy while still providing etiquette overhang. When the eave is not parallel or square with the roof, adjust the first course slightly to compensate. If required, additional adjustment can be made in the second course. If the top course is not parallel, adjust or telescope the last course of tile slightly to compensate. Extra care should be taken when you have a short tile course as it will display variations. When the roof plan is cut up, you may have to lay out part of the fill from the bottom up as normal and transfer the balance from the top down. In this case it is important to work uniformly down, each side of the roof projections maintaining eave in coursing. The remaining battens are installed at 15 and 13/16 of an inch or 402 millimeters on center. This spacing is crucial to obtain proper panel fit. The most accurate method is to use the batten spacer which will lock into a fasten batten and hold spacing while the next batten is butted to the spacer and fastened.