The planning and construction of a building should be aimed at fulfilling the following requirements:
1. STRENGTH
A wall should be strong enough to take up the loads safely due to its own weight, super imposed loads and lateral pressure such as wind.
2. STABILITY
It should be stable against overturning by lateral forces (due to wind load) and buckling caused by excessive slenderness.
3. WEATHER RESISTANCE
All the external walls, whether of load bearing or panel construction, should provide adequate resistance to rain, sun and wind penetration.
4. FIRE RESISTANCE
The walls should offer sufficient resistance to fire, as they behave as vertical barriers for spread of fire in the horizontal direction. So the walls should be made of such a material which neither ignite nor allow the spread of the fire through them.
5. HEAT INSULATION
It should be possible for walls to attain insulation against heat. For this, the walls are made either thicker, or cavity wall construction is employed. Heat insulating materials are also used in construction of walls.
6. SOUND INSULATION
The walls, both load bearing and non-load bearing, should be made of such materials and by such techniques, viz., cavity wall construction, so as to insulate building against indoor and outdoor noises.
7. PRIVACY & SECURITY
The walls, particularly external walls, should also provide sufficient privacy and afford security against burglary.
In the design and construction of walls, a balance between two primary considerations, namely strength and insulation against elements (such as heat, fire & weather), should be exercised.
Generally hollow concrete blocks or perforated bricks are used now days for construction of building walls, as it satisfies most of the requirements.