In new-construction, you hang drywall on studs and all the edges meet up perfectly with each other and with all the window and door trim. If the carpenters have framed the walls properly, the drywall installers will find this perfect installation surface.
Drywall shims are strips of cardboard that increase the width of a stud so that the drywall hangs flat on the stud.
Building Walls in an Imperfect World
But in a remodeling world, not all is perfect.
Typically, you will find individual studs that are warped, twisted, and bowed studs.
Additionally, entire rows of studs--if they are in good condition--may not be far out enough to match your other work.
So, either you accept the imperfect or you nudge it along until it is closer to perfect.
Far from being technological marvels, drywall shims are dead-simple: very cheap cardboard strips that are harder to create by yourself than one would thin.
- Not to be confused with window or door shims, which are short, tapered, and made of wood or plastic. Drywall shims are flat all the way down their length.
- Length: At 45", they are the perfect length by being the width of a sheet of drywall or half of an eight-foot length, however you choose to look at it.
- Width: At 1 1/2" wide, they are the width of a stud. At about 1/8" thick, they are thin enough to correct shallow irregularities, but can be stacked to address worse problems.
- Hard cardboard that does not compact under pressure, as corrugated cardboard might do.
- Can be duplicated for free by cutting up old cardboard (must be dense, like poster board, not corrugated), veneer board, or even tar paper into slices. But as shims are so inexpensive, it is usually easier just to purchase them. If you need to shim more than 1/8", just buy wood lath.
How Do You Use Drywall Shims?
- Bring a Wall Forward a Bit. If you need to bring a wall forward just a little bit in order to meet other work, drywall shims laid in equal numbers on every stud will do this.
- Correct a Bowed-Out Stud. Build up several shims of gradually increasing length to fill in a bow. You cannot just lay full strips across the bow, because the bow will transmit to the shim and you will not have accomplished anything. If the entire stud is bowed, it is far better and faster just to sister a stud against the bad one.
- Drywall Butt Joints. In the case of butt joints (where you cannot fill in the recess with drywall mud), you shim up the stud or joist on either side of the butt joint, thus creating a cavity for the mud.
Where to Find Them?
- Amazon: 50-count bundles sized at 1 1/2" x 45" x .060". Buy on Amazon - Strait Flex Drywall Shims
- Local Home Improvement Store: Locate the big stacks of drywall. Nearby should be drywall tools and materials. Locate the drywall tape and mud. They will probably be in this area, likely on a high shelf. Both Home Depot and Lowe's carry the 100-count bundles of Grip-Rite drywall shims.