
After a framed wall is upright but before the joists are nailed to the top plate, it needs to be fine-tuned so it’s plumb and straight along its entire length. My favorite way to do that is with a springboard.
To make a springboard for an 8-foot-tall wall, you’ll need a 12-foot-long 1×8, plus a 4-foot-long 1×8 to serve as a brace. Wherever the gauge block and mason line show the wall isn’t straight, drive three 8d cement-coated nails through the end of the 12-footer and into the underside of the top plate. Then, while sitting or pressing down on the springboard, secure its other end to the sheathing with three more nails. Finally, put the brace against the underside of the springboard, as shown, and nail its lower end to the sheathing as well. On long walls, set up springboards this way every 10 feet.
To adjust the wall, simply pivot the brace along the underside of the springboard until the line just touches the gauge block. Then nail through the springboard and into the top end of the brace. The springboard will hold the wall in place until the top plate is secured to the joists.