Expansion and contraction in buildings materials can result in cracking. Cracks are generally even in width, vertical in direction and non-progressive. Expansion cracking is one of the most common forms of cracking. Concrete roofs can also cause horizontal cracking in supporting walls as the concrete deck expands and contracts Expansion cracking is one of the most common forms of cracking.
The width of the crack will depend on the co- efficient of thermal expansion of the material and the temperature range. It is therefore usual for most cracking to be on the South West facing elevations, exposed to the direct sunlight.
- Straight vertical Crack.
- Crack equal width with all displacement horizontal
- Any cracking on bed joint is hairline from sliding action
- Gaps at ends of lintels, with cracking in brickwork around bearing point.
- Over sail at damp proof course on very long elevations.