Cracks can appear on external walls after construction for a variety of reasons. Some common causes include:
Settlement: Settlement occurs when the ground beneath the building compresses or shifts, causing the building to sink slightly. This can lead to cracks in the walls as the structure adjusts to the new position. It is a natural process, and small, hairline cracks are generally not a cause for concern.
Thermal expansion and contraction: Temperature changes can cause materials to expand and contract. This expansion and contraction can result in stress on the walls, leading to cracks over time. This is particularly true in regions with extreme temperature variations.
Moisture-related issues: Moisture infiltration is a common cause of cracks in walls. When water seeps into the walls, it can weaken the structure, leading to cracks. Freeze-thaw cycles can further exacerbate this issue in colder climates.
Poor construction practices: Inadequate construction techniques or the use of low-quality materials can contribute to cracks in external walls. Insufficient reinforcement, improper curing of concrete, or inadequate joint spacing can all lead to structural weaknesses and cracks.
Vibrations or external forces: External factors such as nearby construction activities, heavy traffic, or earthquakes can generate vibrations that put stress on the walls. Over time, this can cause cracks to develop.
Design flaws: Flaws in the design, such as inadequate load-bearing capacity or improper structural detailing, can lead to cracks in the walls. It is essential to ensure that the design is well-suited to the specific conditions and requirements of the building.
It's important to note that not all cracks are cause for immediate concern. Hairline cracks that do not significantly affect the structural integrity of the building are common and can be repaired easily. However, if you notice significant or widening cracks, it is advisable to consult a qualified structural engineer or construction professional to assess the situation and determine the appropriate remedial measures.