Abstract: A calibrated tape capable of being separated into halves along a central portion thereof. The tape has indicia thereon which represent units of distance, each half of the tape having the same indicia as the other half. The tape is adapted to be secured to a pair of adjacent plates which are used to form the upper and lower plates of a wall of the type having spaced, vertical studs secured to the plates. The plates are first tacked together in side-by-side relationship and the tape is applied to both plates. Then the plates are separated, causing the separation of the halves of the tape, the halves remaining on respective plates to form guides for locating the positions at which the ends of the studs are to be attached to the plates. Several embodiments of the tape are described. A second tape is used over the first tape to represent the locations for window and door openings in the wall.