Functions of mortar

Mortar is a paste of a binding material (cement, lime or mud), fine aggregate (sand) and water, used to join building units. Its functions are:

1. Binds bricks, stones or blocks into a solid mass.
2. Distributes load evenly over the bedding surface of the masonry units, avoiding point loads.
3. Bedding: gives an even, level bed so the units sit properly and the courses stay horizontal.
4. Fills joints, gaps and voids between units, making the wall weather-tight and preventing the entry of rain, wind, dust and insects.
5. Holds fixtures such as door and window frames, hold-fasts and steel bars embedded in masonry.
6. Plastering and pointing: used for finishing walls and floors and for giving a decorative surface.
7. Resists weathering and increases the durability of the structure.
8. Absorbs small movements and shrinkage (flexible lime or mud mortar), and is used for flooring, damp-proofing and as a base for tiles.