Why Slaking is Crucial
In masonry trades, "slaking" is a crucial step after mixing sanded or unsanded grout. Do not skip this step when mixing grout for your mosaic projects - no matter how small your project is.
Slaking means letting your grout rest before applying, allowing the powders to fully hydrate. This resting period enables the ingredients to work together and allows the necessary chemical reactions to occur.
Allowing the mix to slake properly ensures that every ingredient is thoroughly hydrated, resulting in a smoother, stronger application. This leads to better performance and enhanced durability.
So after you have mixed your grout to a “peanut butter” consistency, allow the grout to sit undisturbed for up to 10 minutes. This allows grout to strengthen or “slake.” After it slakes, briefly remix your grout to loosen it again and use immediately. Grout hardens completely after 30 to 60 minutes. If you wait too long after slaking, it's possible that you'll have to dispose of the batch and start again. Adding water does not reactivate grout at this point.
Even if you are mixing small amounts of grout for your mosaics, it is very important you do not miss this essential step.
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Here are some additional good articles/videos about slaking:
Mapei: https://www.youtube.com/watch?v=2tyxq5eAYj8
Home Depot: https://www.homedepot.com/c/ah/how-to-mix-grout/9ba683603be9fa5395fab9012db933cb#