The Cause of Grout Cracks Along a Brick Line

Grout Type

• Before 1930, the grout used to adhere bricks to each other contained sand and lime putty. Oldtime grouts remained pliable and somewhat soft, which allowed them to move freely without cracking. Modern grouts offer exceptional strength, but do not flex. The grout's inability to successfully move if the soil conditions shift causes it to crack easily. Shrinkage of the grout as time passes will also cause cracking to occur along the brickline.

Foundation Settling

• A settling foundation shifts the wall slightly and causes cracking, which shows in the grout and bricks. If foundation settlement occurs, the house will also show other signs such as sloped floors, windows that stick when opened and doors that do not close properly. The soil should undergo proper compaction prior to construction to prevent cracks appearing.

Soil and Trees

• Fine-grained clay soils often heave, contract and expand, especially when wet or overly dry. Large trees in the vicinity can send up roots under the structure which will cause heaving. Any movement of the structure's foundation causes cracks but you may not even realize that the foundation has suffered problems until you notice the cracks in the grout.

Weather

• Cracking of the grout can occur during extreme weather. Heavy snow will put pressure on the entire structure and cracking may begin. Excessively wet weather can also promote cracking. The cracks in the grout may be less visible during dry spells when the grout shrinks. During cold and winter months water can enter the cracks and freeze, which makes the crack expand and become more noticeable.