5 common problems in masonry

Montreal winters can be hard on masonry structures: freezing and thawing periods, extreme cold, rain, de-icing salts, etc. All of these factors contribute to the deterioration of brick and stone walls and facades as well as concrete balconies and staircases..

This is why it’s important to know how to decelerate common masonry problems and when to call a professional. As soon as the first signs of spring appear, take the time to check your siding.

Learn how to recognize these 5 common problems with your masonry walls : 

  1. Crumbling mortar
  2. Crumbling brick
  3. Frost boil formation
  4. Formation of cracks in the masonry
  5. Appearance of efflorescence on the brick

1. Crumbling mortar

Since mortar has a shorter lifespan than brick or stone, it is normal to have to replace it, in part or in whole, well before the masonry itself shows signs of weakness.

Crumbling mortar lets water and moisture into your wall. If the problem is not addressed in time, it will accelerate the degradation of your structure, which could cause major problems such as frost boils.

2. Crumbling brick

Normally, brick should not crumble. The accumulation of water on part or all of a brick wall, as well as periods of freezing, thawing and temperature changes, can cause cracks and eventually cause the brick to spall. Walls in the shade are more likely to be exposed to moisture. Since brick does not dry as easily as masonry, this moisture can be absorbed and can damage the walls and brick joints.

A crumbling brick can manifest itself in several ways :

  1. Scaling : Phenomenon mainly linked to freezing and thawing cycles and atmospheric pollution. The scaling is translated by the detachment of flakes, plates, crusts or films all depending on their size.
  2. Alveolization : Phenomenon created by the wind and its tiny particles that hollow out the brick.
  3. Sandy desaggregation : Phenomenon caused by ascending humidity
  4. Dissolution : Phenomenon caused by rain and air that can contain acidic agents. These agents dissolve the salts contained in the brick.
  5. Delamination: This phenomenon is also linked to freezing and thawing cycles or to a mechanical overload of the structure. The brick then crumbles in the form of sheets.

In order to avoid crumbling and splintering of the brick, you must :

  • Maintain brick joints
  • Keeping shrubs and trees away from brick walls
  • Keep water away from masonry walls
  • Installing eavestroughs and proper caulking on your doors and windows
  • Ensure that water from your balcony drains away from the brick wall

3. Frost boils formation

frost boil is a shrinkage of brick or stone that usually appears at the top of walls. Frost boils are often caused by moisture infiltration, an accumulation of moisture in the walls, crumbling mortar, or rusting at anchors and lintels.

It is important to address this masonry problem as soon as you become aware of it, as frost boils can eventually cause part of your wall to burst or even collapse.

During the repair of frost boils, the masonry company can correct the insulation of your wall to avoid water infiltration and solidify the structure with new anchors and lintels.

4. Formation of cracks in the masonry

Over time, cracks can appear in your foundation walls. They can be caused by various factors, including :

  • Weakening of the foundation walls ;
  • The absence of flashings around openings to prevent water infiltration ;
  • The absence of weep holes at the bottom of walls and openings to drain water ;
  • Corrosion of lintels and steel angles

It can be difficult to detect the cause of cracks. Although not all cracks are necessarily serious, it is recommended to call a masonry expert as soon as they occur in order to obtain an accurate diagnosis.

5. Appearance of efflorescence on the brick

Efflorescence is the formation of whitish stains on your brick or stone walls. It is a natural phenomenon whereby salts and minerals in the material rise to the surface when dissolved by water. 

Efflorescence is generally not a problem of concern.

Once the stains appear, simply scrub the damaged surface with water and a brush or with a store-bought solution. If the stains persist even after a good cleaning, you should contact a masonry professional to help you set up a masonry maintenance plan.


La grande majorité des bâtiments de l’Île de Montréal ont au moins une façade en maçonnerie et la plupart ont été construits dans les années 1800 ou au début des années 1900. Même si la maçonnerie est l’un des matériaux les plus résistants sur le marché, il est normal que le temps laisse ses marques.

Savoir repérer à temps les problèmes fréquents comme l’efflorescence, les moisissures, les fissures, les ventres-de-bœuf ou le mortier qui s’affaiblit peut vous éviter bien des casse-têtes.


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