All buildings, regardless of when or where they were built and with what material, are subject to movement. It can be seasonal shrinkage and expansion due to cold and heat, or slow settling
into the ground below the home can cause the movement. As a result, cracks are a natural part
of any home, whether in the walls or the ceilings. If you are looking at the cracks in your ceiling
and trying to determine if they caused by age or are a sign of structural damage, there are a
few things to look for.
Spider web Cracks
The first, and most obvious, determiner in structural and age-related cracks is their size. Spider web cracks are a normal part of a home settling over the years. They can run throughout the home, not only on the ceiling but also on the walls, floors, grout joints in tile installations and concrete slabs. Alternatively, large cracks that are more than 1/16 inch wide are a sign of structural issues and
should be dealt with.
Matching Vertical Cracks
Cracks that cause concern run across the length of a ceiling and then continue down a wall along
the same line. This is a sign of structural damage, usually related to a weak wall stud or perhaps something that was jarred loose in an earthquake or the settling of the home over time. An inferior foundation can cause significant structural issues and damage to a home. Sometimes the house foundation is set without effective drainage or the ground may even move to disrupt the foundation. Substandard construction of the foundation is another common issue that results in ceiling cracking.
If the foundation does not have sufficient waterproofing under and around basement walls and flooring, this could cause the foundation to sink, which would affect the entire construction of the home. Again, the size of the crack can help you determine if it is a pressing issue or something that has just begun to form.
If your cracks are accompanied by a bow or a “dip” in the ceiling, it is a sign of a large problem.
The joists of a home are meant to hold another floor or an attic above it and remain level, but once support weakens, the ceiling will start to sag as gravity takes over. It’s possible that weight and force from the floor above might cause ceiling cracks. Bathrooms on a floor above need specific floor/ceiling support to carry the weight of the fixtures. Even improperly installed insulation above the ceiling can contribute to sagging and cracking in a ceiling. If it’s not possible to remove or redistribute weight on the floor above the ceiling, you will need to reinforce and strengthen the ceiling to enable it to hold the weight efficiently. If you spot any cracks that also include a sagging section, either along the crack or to one side of the crack, take immediate action.
Location of the Cracks
The location of the cracks in your ceiling is a good way to determine whether or not there are larger issues at play. Although cracks along the edges of a ceiling are a normal part of a home's settling or movement, cracks across the middle of a room can be problematic. Wide, long and multiple cracks mean it's time to call a professional.
Moisture damage from above the ceiling, either from the floor above or from damage to a roof, can cause significant ceiling damage. You may see cracks and crumbling, discoloration or peeling paint. In addition, if your ceiling has drywall tape affixed to it, the tape may separate from the ceiling and hang down in strips. Common sources of moisture that create ceiling damage might be plumbing leaks from the floor above, originating from sinks, bathtubs or a plumbing vent. If you have a significant storm with high winds and excessive precipitation and you suddenly notice evidence of moisture in the ceiling, it’s likely that your home suffered roof damage.
Seams and Joints
The type of drywall installed in a ceiling and the way it was installed can have a significant impact on how the ceiling withstands time. A textured ceiling generally requires thicker drywall to ensure the drywall does not sag or crack – use 5/8-inch or 3/4-inch drywall sheets. If the ceiling is not textured, 1/2-inch drywall sheets may be sufficient for the ceiling. Another important matter for ceiling drywall installation is staggering the butt joints and adjacent drywall sheets across the ceiling expanse. Staggering eliminates stress and movement across the whole ceiling because the joints will not
travel from wall to wall.