Quelles sont les causes des ventres-de-bœuf dans les murs en brique et en pierre?
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What causes frost boils in brick and stone walls?

A Comprehensive Guide to Frost Boils in Masonry Walls by Maçonnerie Montréal


As a leading masonry company in Montreal, Maçonnerie Montréal is dedicated to helping you preserve the integrity and beauty of your brick and stone walls. One issue that can affect masonry walls, particularly in regions with harsh winters, is the development of frost boils. In this comprehensive blog post, we will discuss the causes of frost boils in brick and stone walls and provide expert advice on preventing and addressing this issue.

Understanding Frost Boils

Frost boils are bulges or swellings that appear in masonry walls when trapped moisture within the wall freezes and expands, causing the displacement of masonry materials. Over time, this can lead to structural damage and deterioration. It is crucial to understand the causes of frost boils to prevent their formation and address any existing issues.

Causes of Frost Boils in Brick and Stone Walls

Several factors can contribute to the formation of frost boils in brick and stone walls. These include:

  • Moisture infiltration: The primary cause of frost boils is moisture infiltrating the masonry materials. This can result from poor construction, cracked mortar joints, insufficient drainage, or the use of highly porous or moisture-absorbent materials.
  • Freeze-thaw cycles: In Montreal, freeze-thaw cycles can contribute to the formation of frost boils. When temperatures fluctuate between freezing and thawing, moisture within the masonry expands and contracts, causing the displacement of materials and the development of frost boils.
  • Material composition: The composition of the brick or stone used in the wall can also play a role in frost boil formation. Some materials are more susceptible to moisture absorption and freeze-thaw damage, increasing the likelihood of frost boils.

Preventing Frost Boils in Masonry Walls

Preventing frost boils involves minimizing moisture infiltration and ensuring proper construction techniques are used. Key preventative measures include:

  • Selecting appropriate materials: Choose masonry materials that are less susceptible to moisture absorption and freeze-thaw damage.
  • Proper construction techniques: Ensure your masonry walls are constructed with appropriate mortar joints, drainage holes, and flashing to prevent moisture infiltration.
  • Drainage: Make sure the surrounding area has adequate drainage to prevent water from pooling around the base of your masonry walls.
  • Sealants and coatings: Apply sealants or coatings specifically designed for masonry surfaces to minimize water penetration.
  • Insulation: Proper insulation can help reduce temperature fluctuations within the masonry, thus minimizing the effects of freeze-thaw cycles.

Addressing Existing Frost Boils

If you discover frost boils in your masonry walls, it is essential to address them promptly to prevent further damage. Some repair options include:

  • Repointing: Remove damaged mortar joints and replace them with fresh mortar to restore the structural integrity of the wall.
  • Partial or complete wall reconstruction: In cases of extensive frost boil damage, it may be necessary to partially or completely reconstruct the affected masonry wall.
  • Consult a professional: If you are unsure about the extent of the damage or the best course of action, consult a masonry expert like Maçonnerie Montréal for professional advice and repair services.


Frost boils in masonry walls can pose a significant threat to the structural integrity of your brick and stone walls. By understanding their causes, taking preventative measures, and addressing them promptly, you can protect your masonry structures and ensure their longevity. As a leader in the field of masonry in Montreal, Maçonnerie Montréal is here to help with all your masonry needs, from prevention to repair.