Do not assume your newly framed wall is ready for drywall installation. Most framing lumber is not perfectly straight. When you sight down the length of any particular piece, you are likely to see a crown, or a slight curve. Many builders will ensure the crown in all of the studs of a framed wall are facing the same direction. If they have not done so, there may be high and low spots, which may be noticeable when you install your drywall. Drywall shims can remedy this problem. Unlike shims used to level and plumb window and door installations, drywall shims are much longer -- up to 45 inches long -- to compensate for crowned wall studs.
Things You'll Need
Drywall nails or screws
Use a 4-foot level as a straight edge. Place the level horizontally across the wall studs where you are installing the drywall sheet. Note any gaps between any of the wall studs and the edge of the level. Measure the width of each gap with a measuring tape. Mark the gap measurements onto the corresponding stud with a felt-tipped pen.
Place the sheet of drywall into position. Screw or nail -- depending on which attachment method you are using -- through the sheet and into the wall studs where no gap was detected with the level.
Select a shim that is equal in thickness to the measurement of one of the gaps. Insert the shim into the gap between the drywall sheet and the wall stud. Screw or nail through the sheet, the shim and into the wall stud.
Repeat the process until you have shimmed and secured all the gaps between the drywall sheet and the wall studs.
Drywall shims are available as kits from home centers or lumberyards. You can also use various thicknesses of wood lath as drywall shims. If you have access to a table saw, you can rip scrap pieces of lumber to any thickness you desire to be used as drywall shims.