According to Walker's, when metal siding is laid on roofs, the end lap should be how many inches?

• A. 1 to 2 inches
• B. 2 to 4 inches
• C. 3 to 6 inches
• D. 6 to 9 inches

Answer: (C)

End laps mark the overlap where one panel ends and the next begins, and on a roof that joint has to withstand rain, wind, and the expansion and contraction of metal. A 3 to 6 inch end lap provides a sturdy, wide enough overlap to keep water out and to accommodate movement without opening the seam. If the end lap is too small, water can bypass the joint and the panel movement can loosen seals over time. If it’s much larger, it can complicate installation and create unnecessary overlap that traps debris or interferes with flashing. So, the 3 to 6 inch range offers a reliable balance between waterproofing and practical installation, as Walker’s specifies.