The short answer
Moisture Is the Primary Culprit
Drywall itself does not have a strong smell when dry. The odor develops when water gets behind or inside the wall. This can happen slowly from a small pipe leak or suddenly from a flood. The porous materials in drywall absorb and hold that moisture, creating an ideal environment for microbial growth that produces the smell.
The source of the moisture might not be obvious. A slow leak from plumbing inside the wall can go unnoticed for weeks. Condensation from poor ventilation or a one-time spill that wasn't fully dried can also be the cause. The smell is a warning sign that water is present where you cannot see it.
Mold and Bacterial Growth
The musty smell commonly associated with wet drywall is often from mold. Mold spores are everywhere and only need moisture and organic material to grow. The paper facing on drywall provides a perfect food source. As the mold colony expands, it releases microbial volatile organic compounds, which are the source of the distinct odor.
Bacteria can also cause odors, sometimes producing a sour or rotten smell. This bacterial growth can occur before visible mold appears, especially if the water was contaminated, like from a sewage backup or a dirty appliance line. Both mold and bacteria need to be addressed to stop the smell and protect your home's air quality.
Why You Should Not Ignore It
Ignoring a drywall smell allows the moisture problem to worsen. Continued dampness can compromise the structural integrity of the drywall and the wooden studs behind it. This leads to softening, sagging, and eventual collapse of the wall material. The cost to repair structural damage is much higher than addressing a small, contained leak early.
Prolonged moisture and mold growth can affect your health. Airborne mold spores and compounds can trigger allergies, asthma attacks, and respiratory irritation. While not all molds are toxic, any mold should be removed. If you or family members start feeling unwell, see a doctor and have the home inspected.
Steps to Diagnose and Resolve
Your first step is to stop the water source. If you can find and safely access a shutoff valve, turn off the water to that area. Then, contact local water damage pros. They use tools like moisture meters and thermal cameras to map the full extent of the dampness without unnecessary demolition.
The pros will develop a drying plan. This often involves removing the baseboards and cutting small inspection holes in the drywall to access the wall cavity. Industrial air movers and dehumidifiers are then used to dry the area thoroughly. Only after it is completely dry can the cause of the smell be permanently eliminated and repairs begin.
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Phones are answered 24/7 for Meridian and nearby communities.
Call Now (208) 537-2633Frequently asked questions
Can I just paint over a smelly drywall patch?
No, painting will seal the moisture and odor inside. The smell will return, and mold will continue to grow unseen. You must first find and fix the water source, then completely dry or replace the affected drywall before any painting or sealing.
Will the smell go away if the leak stops?
Not if the materials remain damp. Simply stopping the leak does not remove the absorbed water. The wall cavity needs active drying with professional equipment. If mold has already grown, the contaminated materials must be removed to eliminate the odor source permanently.
Does homeowners insurance cover fixing smelly drywall?
It might, if the cause is a sudden, accidental event like a burst pipe. Damage from long-term neglect or lack of maintenance is often not covered. Policies vary, and your insurer decides what is covered. Document the damage and contact your insurance company to start a claim.