How to Measure Stair Tread Depth and Nosing Overhang

Place a tape measure at the very front edge of the stair tread, ensuring it is flush with the nosing. Extend the tape measure straight back along the tread surface until it meets the riser (the vertical part of the step). Record this measurement as the tread depth.

Position the tape measure at the vertical surface of the riser directly beneath the nosing. Extend the tape measure horizontally out along the underside of the nosing until you reach the very front edge of the tread. Record this measurement as the nosing overhang.

Place the tape measure at the very front edge of the stair tread's nosing. Extend the tape measure straight back along the tread surface until it reaches the riser. This measurement should be the sum of the tread depth (from step 1) and the nosing overhang (from step 2). Record this total depth.

Create a clear record of all measurements taken for each stair tread. This typically involves noting down the tread number, the tread depth, and the nosing overhang for each step. It is advisable to also record the total tread depth. This documentation is vital for ordering new treads or for ensuring uniformity during a renovation.