There are various factors that lead to damages and deterioration of brick facades such as temperature, humidity, size, and shapes etc. These factors affecting brick facades are discussed.
Fig.1: Deteriorated Brick Facade of a Building
Fig.2: Brick Facade Adhered to Load Bearing Wall
What are the Causes of Brick Facade Deterioration in Buildings?
Causes for building brick facade deterioration include:
- Factors related to the shape and fitting of brick façade
- Brick facade damages due to temperature gradient
- Deterioration of brick facade due to humidity variations
- Brick facade damages because of construction practices
- Deterioration of brick facade because of environmental conditions
Brick Facade Deterioration due to Shape and Fitting of Brick Facade
There are two main factors that may contribute to deterioration and damage of brick façade, namely, grip material quantity placed at the back of the brick and brick smooth cutting.
So, the connection between the brick facade and bearing wall is based on the resistant and deformity of the material used to create the link between bearing wall and brick facade.
It is necessary to ensure these properties of the gripping material through tests to have good adherence.
The gripping material such as mortar should behave elastically and does not suffer damages under stress. This property could be achieved to a certain extent by introducing lime to the mortar.
Brick Facade Deterioration due to Temperature Gradient
Temperature variation would lead to differential movements or deformation of mortar and brick facade. So, when the temperature rises, the expansion of mortar and brick facade would be different because their masses are different.
To eliminate or decrease the degree of damage due to temperature variations, it is recommended to make the resistance of mortar joints smaller than that of brick.
This will guarantee the breakage of mortar prior to the brick because the repair of the mortar joint would be easier compared to the brick.
Fig.3: Damage of Brick Faced due to Temperature Variation
Deterioration of Brick Facade due to Humidity Variations
The ingression of humidity into the brick facade and mortar joints lead to their expansion and contraction.
By and large, this movement does not lead to brick facade or mortar joint deteriorations, but if it is persistent it would impair damages.
There are several factors that help the penetration of humidity into the facade bricks and mortar joints. For example, construction practice, the direction of the structure, improper selection of bricks (poor brick quality) and quality of mortar and additives.
It is claimed that the cracks developed in mortar are the major cause of humidity penetration. This problem cannot be tackled unless the factor that leads to humidity penetration are eliminated.
Fig.4: Humidity Penetration Caused Expansion of Brick and Mortar, Mortar Joint Failed
Brick Facade Damages Because of Construction Practices
The construction practice is another factor that may lead to deterioration of brick facade. Certain construction errors such as omitting the provision of proper means for ventilation in specific areas of the brick facade lead to retain and accumulate the penetrated water which is not desirable.
The next construction error is caving mortar when bricks are joined together. This would encourage the retention of water which is again not favored.
Clearly, the presence of water would lead to expansion and contraction of bricks and mortar joints and consequently deterioration would occur such as buckling or bricks and damages of materials used to connect bricks to the bearing wall.
The solution of this problem is to eliminate construction errors at first place.
Deterioration of Brick Facade due to Environmental Conditions
Certainly, the environmental condition would influence the response or behavior of the brick facade. The environmental condition in combination with the pores of the brick facade will influence the quantity of humidity with the facade brick.
Evaporation of moisture in facade wall is greatly affected by the conditions around the structure. For example, humidity in the air around the structure, ambient temperature and wind velocity influence the rate of evaporation in the brick facade wall.
The rate of evaporation in the brick facade would increase when the degree of temperature increase. However, the increase of humidity in the air surrounding the structure would decline evaporation.
It is obvious that brick facade suffers from deterioration mainly during wetting and drying. Therefore, it is evident from the above discussion that environmental condition would substantially influence the brick facade damages.
Finally, it is proven that the brick facade walls, which are frequently exposed to rain and wind, will experience greater and quicker deterioration. So, this explains the importance of the direction of the structure.