Expansion Joint
A drywall expansion joint (or control joint) is a deliberate gap or flexible connector placed in long drywall runs or large surfaces to prevent cracking from building movement, thermal expansion/contraction, and structural shifts, allowing the drywall to expand and contract without failing, often appearing as a decorative groove or bead with a flexible center. These joints are crucial in large areas like hallways or garages and are installed using specialized vinyl, metal, or plastic trim that is mudded in and finished to provide a controlled break, unlike regular tape.
How they work
- Creates a flexible break: Instead of taping over a natural seam, an expansion joint provides a designed *channel for movement.
- Accommodates movement: It allows framing to expand and contract, relieving stress that would otherwise crack the drywall.
- Uses specialized trim: Products have flexible centers (like a "V" groove) and flanges to be set into the gap, with removable strips for clean finishing.
Where they are used
- Long, uninterrupted walls or ceilings.
- Where structural control joints exist in the framing.
- Between different building sections (wall-to-wall, wall-to-ceiling).
- High-humidity areas or large garages where movement is common.
- Watch this video to see how to install an expansion joint on a ceiling: