Masonry Magazine March 2003 Page. 46
Control JOINTS
CONTROLLING SHRINKAGE CRACKS IN Concrete Masonry Walls
By Maribeth Bradfield, P.Ε., Arlington, Va.
ANY DESIGNERS USE CONCRETE masonry based on masonry's rich history, unique design flexibility, and proven durability to ensure a beautiful and sound structure for generations. Aspects such as the structural design, aesthetics and energy efficiency are all important considerations influencing the ultimate success of the project. An additional consideration that should not be overlooked is the control of shrinkage cracking, which can detract from the visual continuity of the design and could potentially lead to water penetration problems.
Careful structural design and detailing will prevent the majority of wall cracks those due to excessive deflection, structural overload and settlement, for example. Shrinkage cracks, however, are not structural-they will not weaken the building-but they can be unsightly and can lead to water penetration in exterior walls. Because they are strictly an aesthetic concern, efforts to control shrinkage cracking are typically applied to exposed above grade walls. Attention to the following guidelines will help keep shrinkage cracks to a minimum.