The short answer
What a Leak Does to Drywall
Drywall is made of gypsum plaster pressed between layers of paper. It is strong when dry, but water breaks it down fast. Even a small, slow leak can soak into the wall and leave a brown stain within hours. The paper surface bubbles and peels, and the gypsum core softens like wet cardboard.
If the leak continues, the damage spreads. The wall may bulge or sag under its own weight. Paint and wallpaper start to blister. In serious cases, the drywall crumbles and falls apart, leaving a hole. The longer water sits inside the wall, the more likely the damage becomes permanent.
Mold Can Follow the Water
Mold needs moisture, warmth, and a food source to grow. Drywall and the paper facing provide the food. Once a leak wets the wall, mold spores that are already in the air can land and start growing within 24 to 48 hours. You might see black, green, or gray patches spreading across the surface.
Mold can also grow inside the wall cavity, hidden from view. It releases spores into the air, which can cause coughing, sneezing, or headaches for some people. If you or your family feel unwell from mold exposure, see a doctor. A mold professional can inspect the wall and recommend safe removal steps.
How to Assess the Damage
Start by finding the source of the leak. Check for dripping pipes, leaking appliances, or roof issues. Turn off the water supply to the room if you can locate the shutoff valve. If the leak is from a pipe or appliance, a plumber or appliance repair person can fix the source. For a roof leak, a roofer may be needed.
Once the source is stopped, you can assess the wall. Press on the wet area with your finger. If it feels firm, the drywall might dry out and be saved. If it feels soft or crumbles, the damaged section will need to be cut out and replaced. Local water damage pros can test the moisture level in the wall and tell you how far the damage goes.
What the Pros Usually Do
For a wall that is only stained but still solid, the work often involves drying and cleaning. The pros use air movers and dehumidifiers to pull moisture out of the wall and the surrounding structure. They may also treat the area to prevent mold growth. If the drywall is too damaged, they cut out the wet section and replace it with new drywall.
The cost depends on the size of the damage, the source of the leak, and how long the water sat. A small stain might only need a patch and repaint. A large soaked wall may require removing insulation, drying the framing, and replacing multiple panels. Local water damage pros can give you a clear idea of what your specific situation involves.
- Dry the wall with air movers and dehumidifiers
- Treat the area to discourage mold growth
- Cut out and replace damaged drywall sections
- Inspect the framing and insulation for hidden moisture
- Repaint the repaired area to match the rest of the wall
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 (801) 383-0232Frequently asked questions
Can a small leak stain my wall permanently?
A small leak can leave a brown stain that is hard to cover with paint alone. The stain comes from tannins and minerals in the water that soak into the drywall paper. Sealing the stain with a stain-blocking primer before repainting often works. If the drywall is soft, the stained section may need replacement.
How long does it take for mold to grow after a leak?
Mold can start growing within 24 to 48 hours after water soaks into drywall. The speed depends on temperature and humidity. Warm, damp conditions speed up growth. Drying the wall quickly with fans or dehumidifiers can slow mold, but you still need to clean or remove any mold that appears.
Should I replace the whole wall if one section is wet?
Not always. If only a small area is wet and the drywall stays firm, you can often cut out just the damaged section and patch it. If water has soaked a large area or the wall is sagging, replacing a larger panel may be necessary. A professional can measure the moisture to decide the right approach.