Can you use grout instead of mortar?
Consequently, can grout be used in place of mortar?
Using Mortar Instead of Grout Because mortar is thicker than grout, it's not recommended as a grout substitute for most tile projects. The mortar doesn't flow as grout does, and can leave gaps or holes behind as it dries. Only use mortar in place of grout if the tile specifically calls for it.
Similarly, you may ask, how is grout different from mortar?
The main difference between mortar and grout is the amount of water in the mix. Grout must be made with enough water to make it pourable or pumpable but not with so much water that the grout components segregate. In addition, coarse grout contains larger aggregates than mortar or fine grout.
Use a trowel to smear on your grout generously. Then, use a large tile float to push the grout into the spaces between the bricks and scrape over the brick faces so that you have a thin layer on the bricks.