When added to grout this product will improve the flexibility and reduce water permeability of the product.
When tiling shower floor areas with Carrara Mosaics we would recommend adding this product to the grout in a ratio of 50% water and 50% booster!
This product is a must if tiling onto wooden floors.
Technical Data Sheet
http://cdn.ardexaustralia.com/pdf/products/datasheets/tiling/ARDEX%20Grout%20Booster%20Datasheet.pdf