Q: Precut studs obviously save labor and material, but how was their length determined?

A: West Coast: Tim Uhler, lead framer for Pioneer Builders in Port Orchard, Wash., responds: Here, precut studs for 8-foot walls are 92 5/8 inches, which makes the overall height of the wall framing roughly 97 1/4 inches with three plates (two top and one bottom). I’ve always been told that this stud length was meant to accommodate 5/8-inch drywall on the ceiling--you could butt two 4-foot-wide sheets up against the lid and still keep the drywall about 1/2 inch off the floor. The bottom edge of the drywall would roughly split the bottom plate. But even with the stronger, lighter 1/2-inch drywall, the bottom edge still has plenty of nailing on the bottom plate.

With 9-foot ceilings, the precuts are 104 5/8 inches, which gives us an overall height of 109 1/4 inches. (In my experience, the precut studs for 9-foot ceilings always seem to come a hair long for some reason). In this case, we butt two 54-inch-wide sheets of drywall against the ceiling, which gives us the same clearance at the bottom. Beyond that, the precuts do save us and the drywall installers a significant amount of time and energy.

A: East Coast: John Spier, owner of Spier Construction, a building and remodeling company on Block Island, R.I., responds: In my opinion, the best thing about precuts is they come off the pile in a usable (and reliable) length (92 5/8 inches), and you don’t have to take time to cut them all to length. Whereas if you buy a stack of so-called 8-foot lumber, the lengths always seem to vary a bit and you have to cut every one to length.

If you strap your ceilings, as many East Coast carpenters do (see “Strapping Ceilings,” Sep/14), while using standard precut studs, you usually have to rip a bit off the edge of one of the sheets of drywall before putting it on the wall. This obviously defeats the purpose of the precuts but is still better than cutting a couple of inches off every stud in the house. One way around that problem is to add a third top plate layer made from rips of subfloor sheathing that are wider than the wall plates. The extra width becomes the perimeter strapping, and the precuts can work as they’re supposed to. (This perimeter detail also becomes a good place to transition an air barrier from the outside of the walls to the interior of the ceiling.)

I’ve heard carpenters from other parts of the country mention different precut stud lengths; for example, 93 inches (in parts of the South) or 92 1/4 (in parts of California). There must be local reasons why this makes sense. Anyone know?