Common causes of cracks
1. Expansion cracks in masonry wall
These cracks are caused by change in either temperature or moisture content in the wall. These cracks can be observed above the window or door opening and have consistent width. Increase in temperature especially during the day causes the wall to expand and result to cracks if the expansion effect due to temperature was not taken into consideration during design process. Also when the wall is wet especially the one made of clay burnt bricks, tends to expand due to expansive nature of the material as the result cracks are formed. |
| expansion crack |
Repair
These cracks can be repaired by using sealant materials. They don't have any structural effects.
2. Ground heaving
This is common in clay soils, when it is waterlogged tends to heave. This induces cracks to the foundation then to the wall. Cracks due to ground heaving are always wider at the base of the wall.Ground heaving may be caused by
- Weather change
- Removal of tree near the house
Repair
Underpinning is likely to be an appropriate measure. Also, using a pile foundation helps to overcome the effects of ground heaving.
3. Subsidence
Subsidence is a very specific issue that occurs when the ground under your house collapses, or sinks lower, taking some of the building’s foundations with it. |
| crack due to subsidence |
Repair
Can be repaired by underpinning.
4. Cracks above opening of the wall.
Causes:
- Removal of door or window without adequate propping.
- Inadequate bearing
- Load applied directly over opening
- Absence of lintel.
Repair
Replacement of lintel.
5. Settlement
This is the vertical downward movement of the soil. Cracks occurs when differential settlement happen where by soils at two different points exhibit different magnitude of settlement.
