Lintel is a horizontal member, which is placed across the openings, left in the wall for the provision of doors, windows etc. Width of the lintel is equal to the thickness of the wall. Depth of the lintel varies from 100 to 150 mm.
Slabs are constructed to provide flat surfaces, usually horizontal in building floors, roofs, bridges, and other types of structures. The slab may be supported by walls or by reinforced concrete beams usually cast monolithically with the slab or by structural steel beams or by columns, or by the ground.
Differences between lintel and slab are: