What is the recommended depth for grout joints when setting quarry tile on fresh set mud?

The recommended depth for grout joints when setting quarry tile on fresh set mud is typically 1/4 inch. This depth allows for sufficient grout to fill the joint effectively, providing stability and flexibility while ensuring a good bond between the tiles. A 1/4 inch joint is also practical for managing movement and accommodating any slight imperfections in the tile edges or surfaces.

Using a grout joint that is too deep, such as 1/2 inch or 3/4 inch, can lead to issues with the grout cracking or shrinking as it dries. Additionally, a joint that is too shallow, like 3/8 inch, may not adequately fill the space and could result in tiles shifting or loosening over time. Therefore, 1/4 inch is the optimal choice for performance and durability in installations of quarry tile.