Mortar is considered tile adhesive. Grout is the filler applied between the tile spaces to fill and seal the gaps.

Can mortar be used as 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. Over time, the mortar can crack and weaken or cause water to leak through.

What is stronger grout or mortar?

Strength. When it comes to the strength of the two materials, you might be surprised to learn that grout is generally stronger than mortar. This might seem counterintuitive, as you might think the stuff needed for building brick walls would be stronger than the gap filler for the tile in your bathroom.