Mechanical Agents

• Mechanical agents are those which tend to impose a physical force on the building .
• They can be static & permanent , such as ground pressure , or static and temporary such as transient load . Alternatively , the force can be dynamic such as wind or vibration .
• Mechanical forces which act on & within components do manifest themselves as building defects as follows :

1. Frost action through the formation of ice crystals within components already saturated with water .
2. The combined action of rain and wind in forcing pollutants into the building materials .
3. The erosion effect of wind & rain on the external fabric .
4. Abrasion , especially to such items as floor finishes