Bricks were exposed in this room as far as we could get away with. Previously the closet area had been framed out for a door way, so it was closed from about 6 feet up. The whole closet area was opened up to allow for the installation of more shelves, and to give the room a bigger feel. As usual the walls were ground down to remove mortar from surface of the bricks. Small holes in the mortar were patched, and the surface wiped clean with a big sponge and water. We applied 4 coats of a satin finish oil-based polyurethane to seal the wall up really well. The first two coats usually get soaked up by the bricks and it hardly looks like you applied any poly at all. The third coat might give you an even look, but usually it takes the 4th coat to finish the job. The polyurethane will bind the sandy mortar together (in this case the mortar is over 100 years old) and not a grain of sand will fall. Without a finish or with just something like Thompson’s Water Seal, old mortar will deposit an ongoing layer of sand all along the baseboard below it, in perpetuity.