The tools for measuring stair treads and risers haven't changed in years: They're accurate, inexpensive and easy to use. With the exception of specialised equipment, the average do-it-yourselfer probably already owns some of the tools for measuring stair treads and risers. Learn about the design and purpose of stair layout tools, and you can gather the tools that suit your project.
The common tape measure gauges the depth of treads and height of risers for repairs and replacement. Because treads and risers rarely exceed 12 inches, you can use nearly any tape measure to determine the dimensions of existing treads and risers. When measuring existing stair treads, extend the tape measure's tang to the tip of the tread's nose. The term "tang" refers to the small metal clip at the end of the tape, and the term "nose" refers to the curve at the protruding edge of a tread.
Carpenters use framing squares not only to measure treads and risers but also to lay out their position on "stringers," the support members that run beneath treads and risers. The common framing square looks like the letter L. The long leg of the L is called the blade, and the short leg of the L is called the tongue. A framing square's blade is usually thicker than its tongue. The legs of the tool meet at a right angle, and increments of measurement, such as centimetres or inches, are etched across the surface of both sides. To measure treads and risers, you can butt the square against either a tread or riser and read the measurements from the tongue or blade's surface.
Stair Measuring Jigs
Like a rectangular version of a folding hand fan, a stair measuring jig expands to meet the ends of treads and risers or contracts into a tidy, self-contained nest. Typically made of sheet metal or rigid plastic, stair measuring jigs generally consist of three flat plates. When collapsed, the plates form a neat stack and, when expanded, the plates form a wide rectangular. A series of aligned channels allows the jig's plates to move back and forth. To use a jig, the carpenter butts the tool against a tread or riser, extends the jig's plates to the end of the tread or riser and secures the plates in place by turning the tool's locknuts. The carpenter removes the jig from the tread or riser, and uses a tape measure to decode the dimensions from the jig.