Material Conditions Series Part 1: Cracks and Crack Systems

Each week we’re bringing you an in-depth look at one of the standard conditions we encounter and document during inspections of buildings and civil structures. 

Part 1: Cracks and Crack Systems in Masonry

Crack system through joints in brick

Cracks of varying degrees of severity are almost always found during investigations of stone, brick, concrete and terra cotta building materials. Cracks can be limited to a single masonry unit, or can occur as crack systems through multiple units, through the mortar joints only, or through both units and joints. Severe crack systems can reach horizontally across entire facades, or can extend vertically for many floors. Crack systems that follow the masonry joint diagonally are often called “step cracks”.

293-67 Stone_Crack System units 2013-8

Crack system through units in granite

The forces that cause cracking in masonry and concrete have a variety of causes, including thermal expansion, water infiltration and freeze-thaw stresses, faulty design or installation, inappropriate repairs and repointing, and settlement. Patterns and directions of cracking can give clues to the underlying causes. Repair in the near future is recommended for most cracks and crack systems.

Severe crack through a terra cotta unit

Severe crack through a terra cotta unit

Next in this series: Crazing

Click here to see all posts in this series.

Click here for an index of all posts in this series, or download a pdf of the complete series.

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