Since doors and windows are provided in the openings in the walls, a discontinuity is formed in the walt, in the vertical direction. Lintel. are therefore essential. A lintel is a horizontal structural member provided ove’r the doors, windows or other openings, lo span the gap, so as to support the super-imposed load carried by the walt aboye the opening. Linteis may be made of timber, stone, steel or reinforced cement concrete (R.C.C.).
Sometimes, an arch may be providcd to span the opening, in the place of a lintel. An arch is a structure consisting of a number of small wedge-shaped units and jointed together with moflar, which is construcied to bridge across any opening in the walt. The arch may also be constructed in R.C.C.