Question: Can I install tile directly over the brick on both the fireplace front and hearth. If so, what type of adhesive (thinset) should I use? Also should I first lay a layer of adhesive/thinset to level the surface by filling in mortar depressions? Answer: YES. Clean it first. Make sure there is no smoke residue and or brick sealer on the brick. Use Latex fortified thinset adhesive. YES. Chip off high spots if the brick surface is uneven. Don't lay thinset any thicker than 1/4" to 3/8" at a time. It will shrink and crack.