To address yellowing tile grout, first scrub the affected area with a mixture of hydrogen peroxide and baking soda. Rinse thoroughly and apply a specialized grout sealer to prevent future stains. Regular cleaning with a pH-neutral cleaner and annual resealing maintain grout integrity.

Yellowing grout often results from mold, mildew, or chemical stains that penetrate porous surfaces. A 2021 study by the Journal of Building Materials found that 60-70% of grout discoloration stems from moisture retention, creating an environment for biological growth. Mold spores thrive in damp conditions, with humidity levels above 60% accelerating their proliferation. The Tile Council of North America reports that improper sealing allows 85% of stains to penetrate grout, while properly sealed grout resists stains 3-5 times longer. Hydrogen peroxide, a mild oxidizer, breaks down organic matter without corroding tiles, while baking soda neutralizes acidic stains. Sealants form a hydrophobic barrier, reducing water absorption by up to 90%, as demonstrated in ASTM C920 testing. Regular maintenance prevents recurring yellowing, saving 30-40% on long-term repair costs compared to reactive fixes. Industry data shows homes with sealed grout require 50% fewer deep清洁 treatments over five years.