"On pitched ceilings, it may help to use a chalk line and level to ensure straight lines. Also, the use of a Nail Gun is very helpful in this task, as nailing over one's head can quickly become tiring. Not to mention, the job goes much faster."
I just strapped and sheet rocked a ceiling but on part of the strapping hangs about a half in two low. How do you guys level your strapping? I could see using shims and a level and working down one piece at a time but how does the string work ?
Once you establish both ends of the strapping to be straight and/or level around the perimeter of the ceiling, you pull the string line down the length of each strap as a straight reference. Clamp the string on both ends with a 3/4" spacer under it, so that it will not be bent any low spots in the strap, then use another piece of the 3/4 as a "go/no go" gauge at each joist location. Then tap down and shim as required. This assumes that you have set up the perimeter with the known lowest point as a benchmark, so you will not need to raise the straps, only lower them.