A lintel spans an opening such as a door or window. It carries the load above the opening and transfers it to the walls on either side. Without a lintel, the wall above the opening would collapse. The lintel is a beam, but it is called a lintel because of its position over an opening. It can be made of steel, concrete, stone, or timber. The choice depends on the load, the span, and the appearance.

Lintels come in several types. A steel lintel is strong and compact, often used in brick walls. A concrete lintel is cast in place or precast, used in block and concrete walls. A stone lintel is used in historic masonry, where it matches the surrounding material. A timber lintel is used in wood-frame construction, often concealed by trim. The lintel must be deep enough to carry the load and long enough to bear on the walls. The bearing length is usually 4 to 8 inches on each side.

Lintel failure is a serious structural problem. A cracked lintel can cause the wall above to sag and crack. A corroded steel lintel can expand and crack the masonry. A rotted timber lintel can crush and drop the load. Lintels must be designed by an engineer, especially for large openings or heavy loads. In historic buildings, lintels are often the first element to fail. They are also the first element to inspect. The lintel is a small beam with a big responsibility.