Why Do Ceiling T Bars Need Thermal Expansion Consideration?

Aluminum’s coefficient of thermal expansion (≈23 × 10⁻⁶ m/m·K) means that a 600 mm panel can grow by over 1 mm across a 20 °C temperature rise. In large ceiling areas exposed to attic heat or solar gain through skylights, this expansion can buckle panels or warp grid joints if not accommodated. To prevent distortion, design reveals between panels of at least 3–5 mm, and specify teardrop-shaped knock-outs in tees that allow slight movement. Perimeter wall angles should include expansion joints every 8–10 m. During installation, panels should be clipped on one edge and free on the opposite edge to slide. Considering thermal movement from the outset ensures flush, gap-free ceilings under all environmental conditions, preserving the integrity of both grid and aluminum panels.