Why do most hangers run wall sheets horizontally instead of standing them up, and what do I do about the butt joints when I go horizontal?

Most hangers run wall sheets horizontally because it's faster, requires fewer joints, and provides better structural shear resistance. Horizontal installation also reduces the chance of tapered edges creating visible ridges.

For butt joints when going horizontal:

1. Stagger end joints - Keep them at least 6 inches from the edge of the previous sheet's end joint. This prevents weak planes in the wall.

1. Use proper joint treatment - Apply joint compound with paper or fiberglass tape. Embed tape in first coat, then apply two additional coats, feathering each wider than the last.

1. Consider the "smiley" technique - Slightly concave the joint compound application so it pulls the boards together as it dries, minimizing gaps.

1. For fire-rated assemblies - Check the specific UL design. Many require Type X board with Type C or X-rated joint compound, and some mandate specific tape types.

1. Tapered edge consideration - When butting a tapered edge against a square edge, you may need to build up the square edge with extra compound to create a smooth transition.

Pro tip: If you're doing this yourself, consider using a drywall lift for horizontal sheets - they're heavy and awkward without one. Also, make sure your framing is properly aligned since horizontal sheets span more studs and any irregularities will telegraph through.

If this is for a fire-rated wall or you're unsure about local code requirements, consult the specific assembly details - improper joint treatment can void fire ratings.

Why Horizontal is Standard:

1. Framing Alignment: Studs are typically 16" or 24" OC. Running sheets perpendicular (horizontal) hits every stud. Running vertical on 8-ft walls often leaves the long edge floating between studs unless you rip the first/last sheet or add blocking.
2. Fewer Butt Joints: An 8-ft wall takes three 12-ft sheets horizontal (two butt joints) vs. four 8-ft sheets vertical (three butt joints + tapered edges on studs).
3. Stronger Wall: Horizontal orientation bridges studs, increasing racking resistance (shear strength) per IRC Table R602.3(1).
4. Easier Finishing: Butt joints fall at a comfortable working height (48" and 96"), avoiding stilts/ladders for the critical taper joints.

Handling Horizontal Butt Joints (The "Non-Tapered" Edge): This is the weak point. Do not just butt them tight and mud.

1. Back-Block (Strongly Recommended): Cut 12"-16" strips of drywall (same thickness). Center them behind the butt joint, screw through the face sheets into the back-block (2 screws per sheet, 1.5" from joint). This creates a slight recess, mimicking a tapered edge. IRC R702.3.1 requires joints to be "moderately backed."
2. Stagger Joints: Never stack butt joints on adjacent rows. Stagger by at least 4 ft (one stud bay).
3. Tape & Mud: Use setting-type compound (Durabond/Easy Sand) for the first coat—it shrinks less. Paper tape is stronger than mesh here. Feather wide (18"-24") to hide the hump.
4. Avoid "Hanging Tight": Leave a consistent 1/8" gap at butts for compound keying; don't force sheets tight (causes popping).

Pro Tip: If the ceiling is already hung, hang the top wall row first, tight to the ceiling. The bottom row butt joint is easier to hide at baseboard height.