When tiling a roof, it's often necessary to cut the tiles to fit. The most commonly used tiles are shingles. This is thin material placed in overlapping layers on your roof. There are three primary tools you can use to cut these common roof tiles, depending in large part on the thickness of the tile and the types of cuts made. Choosing the right tool for the job goes a long way toward cutting tiles that are usable in building or repairing your roof.
Examine the tiles you're using for thickness to determine the tool you will need to use to cut them. Mark the tile with a straightedge along the line to be cut.
Use a utility knife to cut thin tiles. The utility knife should have an easily changed blade--cutting the tiles will quickly dull the knife's edge. Place the tile front first on a stable surface and run the blade of the knife across the rear of the tile along the marked line, pressing firmly. Move the tile to an edge and snap the tile along the cut line, breaking it cleanly. This method typically is used with asphalt tiles and other thin materials.
Use a slate cutter to cut such thicker tiles as slate roofing tiles. A slate cutter is a tool that looks much like a straight-handled paper cutter. Raise the cutting edge from the guide piece on the cutter platform. Place the tile face down along the guide piece, with the edge of the tile pressed securely against the joint of the cutting bar. Pull down the handle of the cutting bar, cutting the tile along the marked line. Thicker tiles may not cut smoothly with a single pull of the bar; for these tiles, you may have to move the tile along the guide piece, moving the tile along the guide as you cut it by repeatedly raising and lowering the cutting bar.
Use a saw equipped with a diamond saw blade to cut formed tiles made with concrete or clay.
Use the tin snips to cut curves into the tiles, working along the marked line. Curved cuts typically are required to deal with any obstructions in the roof that might require a curved tile edge. The tiles will dull the snips over time.
Use a sharp blade when cutting the tiles to make the process easier.