What Are the Causes of Cracks Around Window Edges?

Overloading

• Overloading can create diagonal stress cracks in the wall. These cracks often start at a window frame or a door, but they can start in other places as well. Overloading problems occur when additional stories are added on, or when the weight of the roof or furniture is too much for the beams, joists and studs to bear. Adding a doorway or window without installing a header can also cause overloading problems, as can the use of load-bearing beams that are too small to carry the weight above them. Heavy loads over the lintels can cause cracks that appear at the lintels of windows or doors. Cracks that run through the windows and over the entire wall denote urgent problems that need to be immediately addressed.

Settling

• Most newly built houses settle as the soil under the foundation becomes compacted. Settling can also occur whenever there’s heavy rain after a drought. Normally this isn’t a problem, even though you may discover minor cracks in the drywall. Monitor small cracks and patch them when the house finishes settling. However, if cracks prevent normal operation of a window or door, or if they appear suddenly or keep on growing, you could have a serious problem with your foundation. You should contact a building engineer if diagonal cracks cover the full height of the wall.

Shrinkage

• Vertical cracks can form when concrete dries and shrinks. These shrinkage cracks often develop under a basement window. Normally these cracks are narrow and measure no more than 1/8 inch wide. If vertical cracks are wider than that, or if they’re found in combination with horizontal cracks, you could have a settling problem or a problem with a wall moving or tipping. Shrinkage cracks usually go through the entire thickness of a foundation wall and should be repaired because they allow water to penetrate and enter the building.

Humidity

• According to the Drywall Finishing Council, cracks can also occur around window edges when houses are subjected to humidity changes of greater than 50 percent. The wood framing in the house expands more than gypsum, causing it to crack. Houses built in the high desert are particularly susceptible to this problem.