Why do cracks keep coming back in my drywall?

A drywall crack comes back when the repair fixed the gap but not the reason it opened. Most cracks form where a wall moves, at board seams, in corners and above doors and windows, and a rigid patch over a moving seam splits again. The other common cause is the repair itself: no tape, too much compound, or a coat that dried too fast.

Movement and humidity

Drywall sits on framing that swells, shrinks and shifts with the seasons. USG's handbook says joint cracking, which appears directly over the long edge or butt ends of boards or along the edge of taped joints, is often caused by structural movement and/or hygrometric and thermal expansion and contraction, or by excessively fast drying of joint compounds.^[1] Hygrometric and thermal means humidity and temperature, so a seam that opens every winter and closes in summer is telling you the house is breathing.

USG's finishing guide goes further: "Uncontrolled and fluctuating environmental conditions during and after construction are a root cause of many finished appearance problems and a primary cause of joint cracks and joint ridges."^[2] On long walls and big ceilings, missing relief matters too. Improperly installed or missing control joints will not allow for relief of stresses within or placed upon the gypsum membrane, resulting in cracks.^[2]

Where the crack is tells you why

• A straight line along a board seam or the edge of the tape. This is a joint crack, covered above.
• A diagonal crack running up from a door corner or light fixture. USG notes that these can start where a door, light fixture or other opening weakens the surface: "May originate from corners of doors, light fixtures and other weak areas in the surface created by the penetration."^[1]
• A crack in the corner where wall meets ceiling. USG says this angle cracking can be caused by structural movement, improper application of joint compound in corner angle or excessive build-up of paint.^[1] Repainting a corner many times thickens the paint film until it splits along the corner.
• Cracks next to popped nails. Loose panels will create “fastener pops” and joint cracks.^[2] If the board moves when you press it, see how to fix nail pops in drywall, because the board has to be pulled tight first.

Why repairs fail

The most common mistake is filling a crack with spackle and nothing else. A moving seam needs something to bridge it. For a large crack, USG's repair instructions are to embed paper joint tape in compound to bridge the crack.^[3] Without tape the fill is a thin brittle strip that splits along the old line.

Compound that dries too fast also cracks. USG traces cracks along taped edges to too rapid drying in high heat, low humidity or drafts, over-thinned compound, and too much compound under the tape.^[1] That is why each coat should be thin and fully dry before the next, about 24 hours between applications at 75 °F and 50% relative humidity.^[3]

In a wall-ceiling or inside corner, more compound is not the answer. USG's remedy is to fill only hairline cracks there and not to apply additional compound, which builds up.^[1]

How to repair a crack so it stays shut

1. Press along the wall near the crack. If the board moves, drive drywall screws into the studs on each side first.
2. Look for stains, bubbling or a soft spot. If you find them, stop and find the water before you patch.
3. Widen the crack slightly and remove loose material, creating a groove that is a little deeper and slightly wider than the original crack.^[4]
4. Press compound into the groove and embed paper joint tape over a long crack, drawing the knife firmly so the tape lies flat.^[3]
5. Let it dry, then add a thin second coat if needed, feathering the edges wide.^[3]
6. Sand with a damp sponge, or with 150-grit paper or finer, and wipe off the dust.^[3]
7. Prime the repair so it does not absorb the new paint, then paint.^[4]

If a hairline crack reopens in the same place after a taped repair, the wall is still moving. A flexible patching compound is meant for that case: DAP says Elastopatch maintains flexibility over time, allowing the surface to expand and contract without cracking or crumbling.^[5] Note that it is NOT SANDABLE,^[5] so smooth it as you apply it.

Stop and call a pro if

• The crack keeps widening, or doors and windows start to stick. That points to the structure, not the surface. USG's remedy for cracks caused by abnormal stress from structural deflection is to relieve the stress, then retape.^[1] Surface repair alone will not hold.
• There is a water stain, a sag or a damp spot. USG notes that board sag occurs in ceilings, usually under high-humidity conditions.^[1] Find and fix the moisture first, and see what a cracked or sagging ceiling costs to fix in Virginia.
• The paint is flaking in a home built before 1978. Any renovation, repair or painting project in a pre-1978 home or building that has lead-based paint can easily create dangerous lead dust.^[6] Anyone paid to do the work must be certified in lead-safe work practices.^[6]
• Cracks appear across many rooms at once. One crack is a patch; a pattern is a diagnosis.

Getting help in Virginia

Once you know what is moving, read how to keep drywall patches from cracking again, how much a patch and paint job costs in Virginia and whether to hire a painter or a drywall contractor. Browse more painting answers or the painting category.

When you want a pro to do it, describe the wall once and local contractors will quote it.