The short answer
Start with Simple Tools
A straightedge, such as a 4-foot level or a piece of lumber known to be straight, is your first tool. Hold it vertically against the wall and look for gaps between the edge and the surface. A flashlight helps reveal small shadows that indicate a curve.
A taut string stretched from one corner to the other works in the same way. Pull it tight and measure the distance from the string to the wall at several points. Differences of more than a quarter inch often signal a bow that needs attention.
Measure the Curve
Once you suspect a bow, use a tape measure to record exact distances. Place the straightedge or string at the base, middle, and top of the wall. Write down each measurement so you can track changes over time.
A laser level projects a straight reference line across the wall. You can then measure from that line to the surface at regular intervals. This method is especially useful for tall walls or long runs where a physical straightedge is hard to manage.
- 4-foot spirit level
- 8-foot straightedge
- Taut string or chalk line
- Laser level
- Tape measure
- Flashlight
Check for Moisture Behind the Wall
Bowing often comes from water damage, so a moisture meter is a valuable tool. Pin-type meters push small probes into the drywall to read moisture content. Pinless meters scan the surface without leaving marks. Both help you find damp areas that weaken the wall.
A thermal imaging camera, sometimes called an infrared camera, shows temperature differences that can indicate hidden moisture. Cooler spots on a wall might mean wet insulation or a slow leak. These tools give you a clearer picture of what is happening behind the surface.
Know When to Call the Pros
Simple tools help you notice a problem, but they do not tell you how serious it is. If you see cracks, bulging paint, or a wall that moves when you push on it, stop investigating and get help. Water inside a wall can weaken framing and create mold risks.
Local water damage pros use specialized equipment to measure moisture levels and structural movement. They can also identify the source of the water, whether it is a plumbing leak, roof issue, or flooding. Checking walls after a storm is wise, especially in areas prone to heavy rain.
- Cracks along seams or corners
- Bulging or rippled drywall
- Soft spots when you press gently
- Musty odor near the wall
- Water stains or discoloration
Prevent Further Damage
If you find a bow, do not ignore it. Dry the area with fans and a dehumidifier if it is wet. Remove wet baseboards or drywall if you can do so safely. The longer moisture sits, the more damage it causes.
Fix the source of water first. That might mean calling a plumber for a leaky pipe or a roofer for a damaged shingle. After the source is fixed, address the wall repair. For extensive damage, the pros can handle the drying and restoration work.
Water damage does not wait
Water keeps spreading into floors and walls, so it is worth acting early. Calls are answered 24/7.
Call Now (817) 799-6732Frequently asked questions
Can I use a smartphone app to measure a bowing wall?
Some apps use the phone's sensors to act as a level or inclinometer. They can give you a rough idea of tilt, but they are not precise enough for measuring a slight curve. A straightedge and tape measure are more reliable for home checks.
How much bow is too much?
A bow of less than a quarter inch over 8 feet is often cosmetic. More than that, or if the wall moves when you push, suggests structural damage. Have a professional look at it, especially if you also see cracks or water stains.
What does a moisture meter tell me exactly?
A moisture meter reads the percentage of water in the drywall or wood. Readings above 20 percent often indicate wet materials that need drying. It will not tell you the cause, but it helps confirm whether water is involved in the bowing.