Walls & drywall

Hairline cracks in drywall

Thin, straight hairline cracks are usually cosmetic and caused by normal house settling or seasonal movement, not structural problems.

Difficulty
Easy
Time
30–60 minutes plus drying
DIY cost
$10–$25
Pro cost
$100–$250

Symptoms

  • Thin crack, often near a doorway, window, or ceiling corner
  • Crack doesn't widen noticeably over time
  • No cracking in the foundation or major shifting of doors and windows

Likely causes

  • CommonNormal house settlingWood-frame houses shift slightly with seasons and moisture, cracking paint or joint compound.
  • CommonDrywall tape joint failureCracks that follow a straight line are often at a taped seam between drywall sheets.
  • Less commonStructural movementWide, diagonal, or growing cracks, especially paired with sticking doors, can point to foundation issues.

What to do

  1. Note the crack's direction, width, and whether it's growing over weeks.
  2. Widen the crack slightly with a utility knife so patching compound can grip.
  3. Apply mesh or paper tape over the crack.
  4. Cover with a thin layer of joint compound, feathering the edges wide.
  5. Let dry, then sand smooth and apply a second thin coat if needed.
  6. Prime the patch and paint to match.
  7. Recheck in a few months to see if the crack returns, which can signal ongoing movement.

Tools and parts

  • Utility knife
  • Taping knife
  • Sandpaper
Mesh drywall tapeSearch: “self-adhesive drywall joint tape”

When to call a pro

Call a structural engineer or foundation contractor if cracks are wide, diagonal, growing fast, or accompanied by sticking doors and uneven floors.

Safety

Generally low risk

Generally low risk for a careful person. Stop if anything looks different from what this guide describes.

Related guides

Operator provides AI-generated troubleshooting information. It can be wrong. For safety-critical, electrical, gas, structural, medical, automotive safety, or other high-risk problems, consult a qualified professional.