Exposed brick fireplace surrounds are extremely common and are found in many homes. When the brick doesn't match the rest of your decor, or you just aren't pleased with its appearance, you may wish to cover it up. It is possible to tile right over the brick, turning your fireplace surround into a completely new design. Once the bricks have been covered with mortar and the wall is smooth, tiles of any size, style or design can be installed to update your fireplace surround.
Trowel on a thin layer of thin-set mortar over the bricks of the fireplace surround. Use the flat edge of the trowel to scrape the mortar over the bricks so the end result is a smooth, flat wall of mortar, with the bricks hidden behind it. Allow this mortar to cure overnight.
Lay out the tiles you wish to install over the surround in an area of equal size and shape as the surround to determine the pattern and placement of the tiles. Cut any tiles to fit, using a tile saw, and double-check their size and placement before installing.
Install the tiles on the surround by spreading an additional layer of thin-set over the surround. Scrape the thin-set with the notched end of the trowel to produce a set of ridges in the mortar that are equal in height. Press each tile into the mortar, twisting it slightly into place.
Allow the mortar to dry for 24 hours, then grout the tiles. Pack the joints between the tiles with grout using the flat end of a grout float to ensure even coverage. Wipe up any excess grout with a damp sponge and allow the grout to dry for another 24 hours.