Steel roof decking should be installed so the end laps are a minimum of how many inches over the supports?

The requirement for steel roof decking end laps to be a minimum of 2 inches over the supports is based on structural integrity and load distribution principles. Proper lap spacing ensures that the decking is adequately supported, avoiding potential bending or deformation under loads such as snow, wind, and equipment.

When end laps are placed over the supports, they provide a critical overlap that helps distribute the weight effectively across the framing. This 2-inch minimum allows for sufficient bearing area, ensuring that any forces acting on the decking do not concentrate at the joints, which can lead to failure over time. It also aligns with common industry standards and best practices in construction that promote the safety and longevity of the roof structure.

Choosing a lap distance shorter than 2 inches may compromise the structural performance, while selecting a greater distance is typically unnecessary and could lead to wastage of materials.