The wind girts create nailing surfaces for the siding. We used 2" x 6", Douglas Fir, #2 studs. A few words on studs. There are two different kinds, Douglas Fir and Hemlock Fir. Lowes and Home Depot sell Hemlock Fir and most local "non-big" box stores (we have Bayview Lumber and ProBuild (formerly Lumbermans)) sell Douglas Fir. So what's the difference? Doug Fir is stronger than Hem Fir. #2 basically means, "second best" which translates into some sort of visual defect but not structural, and are cheaper. If your boards don't need to be absolutely straight than it's worth considering. So, step by step, here's how we prepped for the hanging of the wind girts.