Qu'est-ce qui fait craquer un mur porteur?
Reading time: 4'

What Causes a Load-Bearing Wall to Crack?

What Causes a Load-Bearing Wall to Crack?

Welcome to Maçonnerie Montréal, your trusted masonry partner servicing greater Montreal, Laval, Longueuil, South Shore, and North Shore. We pride ourselves on delivering top-notch masonry services and valuable information to our clientele. Today, we're exploring an important topic: what causes a load-bearing wall to crack?

Defining Load-Bearing Walls

To understand what causes a load-bearing wall to crack, we need to establish what load-bearing walls are. These vital parts of a building's structure support the weight from the roof and upper floors, transferring it evenly down to the foundation. Constructed from sturdy materials like brick, concrete, or stone, load-bearing walls are designed to withstand considerable pressure and loads.

Why Do Load-Bearing Walls Crack?

Even the most robustly constructed load-bearing walls are not immune to cracks. Cracks can be triggered by various factors, from natural forces to construction errors. Let's delve into these causes more deeply.

Soil Movement and Settling

Buildings settle over time due to soil movement underneath the foundation. This settling process can lead to cracks in load-bearing walls, especially if the settling is uneven. This phenomenon is more common in older buildings but can occur in new constructions if the ground preparation was inadequate.

Thermal Expansion and Contraction

Materials expand and contract with temperature changes. In regions with significant temperature fluctuations, load-bearing walls may crack due to this continual expansion and contraction.

Pressure and Load Changes

Load-bearing walls are designed to bear a certain amount of weight. If additional load is added to the building, such as a new floor or heavy furniture, it can put undue stress on these walls, resulting in cracks. Likewise, modifications to the structure that disrupt the load distribution can cause cracking.

Poor Quality Materials or Workmanship

If inferior materials were used in the construction of the load-bearing walls, they might not withstand the pressures and loads as expected, leading to cracks. Similarly, poor workmanship can result in weak points in the wall that may crack over time.

Water Damage

Water can significantly damage load-bearing walls, especially if they are made from materials that are susceptible to water, such as certain types of stone or wood. If the wall is consistently exposed to water, it can lead to weakening and eventual cracking.

Recognizing and Addressing Cracks in Load-Bearing Walls

It's essential to address any cracks in load-bearing walls promptly to prevent further damage or potential structural failure. Here's what you need to know:

Spotting Cracks

Typically, hairline cracks aren't a significant concern and are expected as a building settles. However, larger cracks, particularly horizontal or stair-step cracks, could indicate a serious issue.

Evaluating the Severity

If you notice a crack in a load-bearing wall, it's important to assess its severity. Keep an eye on the crack's size and whether it's growing, check if the wall is bulging, and see if doors or windows are sticking, as this could indicate the wall is shifting.

Consulting a Professional

If you're unsure about a crack's severity or the wall's integrity, consult a professional. At Maçonnerie Montréal, we have the expertise to assess, repair, and even rebuild load-bearing walls, ensuring the safety and longevity of your building.


Load-bearing walls are integral to a building's structural integrity. When cracks appear, it's crucial to identify their causes, evaluate their severity, and address them appropriately to prevent more severe structural problems. Whether the cause is soil movement, thermal expansion, added pressure, poor quality materials, or water damage, timely intervention is critical.

With Maçonnerie Montréal, you're never alone in tackling these issues. We offer expert guidance and high-quality masonry services to maintain the stability and longevity of your building.