Headers that are of adequate size to transfer loads to the vertical members must be provided over window and door openings in load-bearing walls and partitions. What are these structural elements called?

Headers are critical structural elements placed above openings like windows and doors in load-bearing walls and partitions. Their primary function is to carry and transfer loads from the structure above to the vertical supports on either side of the opening. This ensures structural integrity and prevents sagging or failure in the wall.

When referring to the options provided, "headers" accurately captures this function directly. However, "double joists" and "trusses" also play roles in supporting loads in different contexts. Double joists are often used in flooring systems to span distances and provide additional support, while trusses are designed to support roofs or larger spans by distributing loads efficiently.

The correct answer encompasses all these structural elements because while they may serve different purposes and are used in different conditions, they all relate back to the fundamental principle of load distribution in construction. Therefore, acknowledging all these components is essential in understanding the broader context of structural support in buildings.