Are control joints required in masonry walls?
Control joints are typically required in exposed above grade concrete masonry walls, where net aesthetic shrinkage cracking may detract from the appearance of the wall, and to limit moisture or air infiltration. Shrinkage cracks in concrete masonry are not a structural concern.
How often does brick need a control joint?
Normally, horizontal control joints are placed every floor over the windows. However, they could also be placed at every floor line with loose lintels over the windows. The control joint could be spaced every two floors, however, the size of the shelf angle and the width of the joint would have to be larger.
How often should you put expansion joints in brick walls?
In order to avoid the detrimental effects of differential vertical movement between the inner and outer leaves of a wall a horizontal movement joint should be provided at no more than every third storey or 9m, whichever is the less.
What are control joints used for in masonry?
Control joints are used to relieve stress induced by small amounts of movement caused by shrinkage during curing or small expansion and contraction movements as the result of absorption and expulsion of moisture in concrete or masonry (brick, CMU, etc).
What is masonry control joint?
Control joints in masonry are vertical weak planes intentionally built or cut into masonry to control where cracking occurs. Control joints should be installed in any masonry assembly that expected to experience net shrinkage over time. Usually, we think of control joints in concrete masonry (CMU).
What are masonry control joints?
Are expansion joints necessary?
Expansion joints are virtually never needed with interior slabs, because the concrete doesn’t expand that much—it never gets that hot. Expansion joints in concrete pavement are also seldom needed, since the contraction joints open enough (from drying shrinkage) to account for temperature expansion.
What is a brick control joint?
A control joint determines the location of cracks in concrete or concrete masonry construction due to volume changes resulting from shrinkage. A control joint is usually a vertical gap through the concrete or concrete masonry wythe and may be filled with inelastic materials.
What is a control joint in concrete wall?
WHAT ARE CONTROL JOINTS? Control joints are planned cracks which allow for movements caused by temperature changes and drying shrinkage. In other words, if the concrete does crack-you want to have an active role in deciding where it will crack and that it will crack in a straight line instead of randomly.
