As our homes age, stresses and possibly even some settlement can contribute to drywall on the interior cracking. This can be over door and window corners, across the ceiling, or randomly on the wall surface. Stress from structural components or drywall tape joints are the most common causes of hairline cracks or thin cracks in the wall. Hairline cracks are common in all homes and can be repaired during routine maintenance as needed.
Most structural cracks occur from movement of the foundation, wind loads, dynamic moisture changes, or just poor quality finish work. As wood framing dries it has a tendency to shrink and curl, which can lead to a number of areas cracking. Dynamic moisture and/or temperature changes can increase drywall cracking. Foundation movement may cause further drywall issues if the home has inadequate drainage or sits on expansive soils.
We can repair many cracks by sealing the affected area and painting over but textured walls may need an extra professional touch to get the patched area to match. When patching drywall, we should use mesh reinforcement tape during drywall repairs to provide additional support to the cracked area.
Drywall cracks at doors and windows can indicate structural movement, or may not. Opening and closing doors or windows can cause movement in the structural members around windows just enough to crack the drywall. Just the process of wood drying out within the wall can cause enough movement to crack the drywall, which is why 1-year warranties on new homes should cover cracking.
Improper bathroom ventilation can increase moisture, leading to drywall cracking as it expands and contracts. ‘Experienced’ homes, or older homes, did not always have exhaust fans installed in bathrooms. Some homes were even built without a window for ventilation. Areas of high moisture and temperature changes will occur more issues.
Truss Uplift Wall/Ceiling Joint
More uncommonly, truss uplift can create cracks at the wall/ceiling intersection at the attic floor. Insulated lower truss members can actually bow upwards or downwards if the temperature or moisture content of the upper truss members in the attic subjected to increased moisture or temperatures. Truss uplift is typical in a house used as a ‘GROW’ house for marijuana. The excess moisture is vented into the attic from the growing room and then absorbed by the upper truss members.
Notice that random electrical outlet that is upside down in the bedroom? Well, an electrician probably installed it upside down to indicate a switched outlet. These outlets are meant for lamps to be turned on at the wall when entering the room. Typically only half of the outlet is switched and the other half is always on, but some homes may be wired differently.
It’s safe to not plug anything in that requires the ground connection into the switched outlet. The additional weight of it upside down can cause the ground to lose contact, creating an unsafe condition considering the fixture will be turned on and off regularly. Standard lamp-cord wiring has 2 blades without a ground plug.
Another area an upside down outlet may be installed is where a doorbell transformer or security system transformer is mounted. It may be oriented so the wire runs towards the ceiling. These plugs are usually heavy and include a screw to keep the plug attached to the outlet.