What Causes Bowed Ceiling Crack? Are Bowed Ceiling Cracks Dangerous?
What Causes Bowed Ceiling Crack?
Large ceiling cracks accompanied by a bowed ceiling can indicate severe structural damage caused by bad water damage, excessive weight on the floor above, or foundation settlement. These types of cracks should be taken seriously and require prompt attention.
Other causes of ceiling cracks include poorly taped joints, truss uplift, house settling, and temperature or moisture fluctuations in an attic. If the cause is simply cosmetic, then it may not require immediate attention.
Are Bowed Ceiling Cracks Dangerous?
Yes. Ceiling cracks can be a sign of serious structural damage, but they are not always an indication of a problem.
Large ceiling cracks with a bowed ceiling are particularly concerning and should be addressed immediately as they suggest severe structural damage caused by water damage, excessive weight on the floor above, or foundation settlement.
Other types of ceiling cracks that may indicate a serious issue include those accompanied by sagging, one large continuous crack that goes across the ceiling and down a wall, or a large number of small cracks. If you notice any of these dangerous ceiling cracks, it is important to seek immediate professional help.
How Do You Deal With A Bowed Ceiling?
To deal with a bowed ceiling, you can either replace 1/2-in. drywall with 5/8-in. drywall or add furring strips and a second layer of 5/8-in. drywall.
To install the new drywall, use a long straightedge and a pile of drywall shims to bring high joists down to flat with the others. Drywall shims are strips of cardboard that increase the forward reach of a stud (that is, the stud’s width) so that the drywall hangs better on the stud.
When installing the new drywall, use a chalk line or laser level to determine how much the defective joists or studs need to be shimmed for the drywall.
When deciding between 1/2-in. and 5/8-in. drywall, it is important to consider both material cost and labor costs.
Generally speaking, 5/8-in. drywall is recommended for ceilings where the span is more than 16″ OC as 1/2″ will eventually sag at spans over 16″ and even at 16″oc in some situations. However, 1/2″ high-strength drywall may also be used in certain situations.
How Much Ceiling Sag Is Acceptable?
Generally, any sagging of a roof is bad and should be addressed as soon as possible. A concerning sag in a roof is when it measures 1 inch or more, and if there is a 2-inch gap between the roof and the ceiling then this is considered major sagging.
While most of the roof may sag, it’s not uncommon for one section to be more affected than the others due to weak spots in the roofing material or improper installation.
Weight on the roof tends to push the supporting walls outward and is often visible as a sag along the ridge along the middle section of the roof. The best way to prevent a sagging roof is by properly maintaining it and repairing any damages as soon as they occur.
What Does A Horizontal Crack On The Ceiling Mean?
Horizontal cracks between interior walls and the ceiling can indicate truss uplift. Truss uplift occurs when roof trusses move slightly due to temperature and moisture fluctuations in the attic, causing the ceiling to pull away from the wall.
This movement can cause a simple hairline crack or create large gaps and cracks along the corners. Truss uplift is most likely to be observed at the ceiling-wall juncture of central interior wall partitions that run at right angles to the direction of the roof trusses.
To prevent truss uplift from causing drywall damage, homeowners can use techniques such as connecting the ceiling and wall drywall while avoiding nailing or screwing the ceiling drywall panel to the bottom of the trusses.
