Our carpet smells odd after cleaning — could the padding be the issue?

Yes, the carpet padding is very likely the culprit. When carpet gets thoroughly wet during cleaning, moisture can penetrate through to the padding underneath, and if it doesn't dry completely within 24-48 hours, mold and mildew can develop, creating persistent odors.

Carpet padding is particularly vulnerable to moisture issues because it's designed to be absorbent for comfort, but this same quality makes it a breeding ground for bacteria and mold when wet. Even professional carpet cleaning can saturate the padding if too much water is used or if the extraction isn't thorough enough. The padding sits directly on your subfloor, often trapping moisture between layers where air circulation is minimal.

In Ottawa's climate, humidity can make drying even more challenging, especially during spring and fall months or in basements where moisture levels are naturally higher. If the smell developed shortly after cleaning and persists despite the carpet surface appearing dry, the padding has likely absorbed moisture and begun to deteriorate. This is particularly common with older foam padding or in areas that were heavily soiled before cleaning.

The most effective solution is typically padding replacement. While you might try professional deodorizing treatments or increased ventilation first, contaminated padding rarely returns to its original condition. When replacing padding, consider upgrading to moisture-resistant options like rubber or synthetic materials, especially in basements or high-humidity areas. A licensed flooring contractor can assess whether the subfloor has also been affected and needs treatment before new padding installation.

If the odor is severe or covers a large area, it's worth having a professional evaluation to determine if the carpet itself needs replacement or if padding replacement will solve the issue. This prevents ongoing indoor air quality problems and protects your subfloor from potential moisture damage.