Grout can appear darker when wet for a number of reasons. Firstly cementitious grout appears darker when wet because it is highly porous.
Water fills the tiny air pockets within the cement, changing how light reflects off the surface. This moisture prevents light from scattering back to your eyes, creating a darker, more saturated appearance. Once the moisture evaporates, the grout should lighten to its true colour.
Cementitious grout is not waterproof, but water resistant, meaning it allows water to travel through it, without breaking down.
If you want your grout to maintain a consistent colour even when wet, apply a high-quality, penetrating grout sealer which fills the pores and repels water.
Alternatively use an epoxy grout system such as BAL Absolute Grout which is waterproof – and forms a barrier against water ingress.
Articles in this section
- Is it possible to mix 2 grouts together to make your own colour?
- Can I use levelling clips with Flexbone 2Easy?
- Why does grout appear darker when wet?
- What can cause silicone to turn yellow?
- What is the maximum depth you can use the BAL Grout Flex Wide Joint?
- Do you treat grout any differently when grouting externally vs internally?
- When mixing up a test batch of Absolute grout what are the quantities?
- Can Rapid Mat be used externally?
- Which side of BAL board do you tile on to?
- Do BAL manufacture a tile adhesive that can be used on a green screed?