Discoloration of Grout on a New Home

Humidity

• If you live in a humid climate it can create problems in the curing process with grout when the humidity is combined with excessive temperatures. While grout will normally cure in around 72 hours, humidity can cause the grout to take longer the dry. In rare cases where excessive humidity is present, such as tropical climates, the excess moisture can cause the grout to dry in phases, leaving behind discoloration due to moisture.

Excess Moisture

• Too much water included in the mixing of the grout can lead to discoloration as the grout is curing, because the various pigments and polymers within the grout do not have enough solidity to bond properly. As a result you can sometimes see splotchy sections of grout that were runny portions during the grouting process and cured differently than the rest of the grout. Always follow the manufacturer’s instructions to the letter for best results.

Heat

• While some amount of heat is desired to help the cement within the grout cure and dry, too much heat can be a bad thing that leaves behind paler sections of the grout as it is evaporating far more rapidly than it was designed to do. For example, grouting a house on the same day the plasterers are coating the outside of the house and have put plastic up on all of the windows is not a good idea when it’s the middle of the summer and already hot outside.

Improper Mixing

• One of the most common types of splotches you can find in grout installations is due to improper mixture of the grout itself. Since the dry mixed polymers are blended together with the pigments for color and the cement itself, everything has to chemically blend completely to give you the manufactured results. Follow the mixing directions and pay specific attention to the slaking period, which is where you let the grout sit for 10 or 15 minutes after you have initially mixed it to let everything soak into the water; then remix it for use on the floor.