01
Design for the actual thickness range
Nominal labels can hide a broad range. Obtain minimum, typical and maximum thickness plus installed weight information. Fastener length, cutting methods and roof loading must reflect the delivered product.
02
Sort to prevent rocking
Place compatible thicknesses together and avoid abrupt high points beneath overlying pieces. Corners need stable bearing; forcing a slate flat with tight nails creates stress rather than correcting the support.
03
Scale the details
Valley widths, step flashings, ridge and hip treatments, snow guards and penetrations must accommodate the thicker roof profile. Details copied from thin uniform slate may be too small or visually weak.