North Carolina General Contractors Practice Exam

Lintels for concrete masonry units are typically made from precast concrete beams. This choice is correct because precast concrete beams provide the necessary load-bearing capacity and durability required in construction. They are manufactured off-site under controlled conditions, ensuring consistent quality and strength.

Using precast concrete beams as lintels allows for quick installation and minimizes the potential for on-site errors since they are precision-engineered components. They can also span larger openings compared to other materials, making them ideal for supporting loads above doors and windows in masonry construction.

While wood beams can be used in certain applications, they do not offer the same level of durability or resistance to fire and pests as concrete options. Steel supports can also function as lintels but may not be the primary choice for concrete masonry units. Reinforced concrete slabs, while related to concrete construction, are not typically shaped or sized for lintel applications, which specifically require a spanning beam profile. Therefore, precast concrete beams are the most suitable and widely used material for lintels in this context.