Refacing a brick fireplace with plaster is an excellent way to give an old fireplace an updated look. A plaster surface is easy to apply and gives you the option of choosing a variety of textures and colours to match the room's decor. Plaster also allows for painted or printed designs, adding to the unique look of the new fireplace surface. The refacing process requires that you create a level surface for your plaster, and then you can mix the plaster and applying it over the new surface. The entire project can be completed in a single weekend, allowing you to quickly create the look you envision.
Completely clean the brick surface, removing any dirt from the bricks.
Measure the area of the brick fireplace to be refaced, and then cut the cementitious backer board to fit. Cementitious backer board is noncombustible and suitable for use as a fireplace facing as long as it is installed according to the manufacturer's instructions. It is not suitable for use within the fireplace itself.
Apply a layer of bonding mortar 2.3 mm / 3/32 inch to 6.35mm / 1/4 inch thick onto the brick surface using a trowel. The mortar will ensure a level surface for the backer board.
Place the cementitious backer board onto the mortar, nailing it into place with galvanised nails. When pressing the backer board into place, use firm pressure to make sure there are no spaces between the backer and the mortar. Use the trowel to remove any excess mortar that may escape from the edges of the cementitious backer board. Allow the mortar to set overnight before continuing.
Place the tape over any joints in the backer board to prevent movement in the mortar or bricks beneath the board translating to the plaster surface, causing cracks in the plaster.
Prime the backer board with a thin layer of drywall compound applied with a broad knife. Once it's dried, sand it slightly to provide a suitable texture for the adherence of the plaster.
Mix the plaster according to the manufacturer's instructions with a spatula, and then remove the excess water from the top of the plaster using a sponge. If desired, add colourant during the mixing.
Apply a thin coat of plaster to the board using the large spatula angled at a 15 degree slope. Give the first coat 10 hours to dry, and then apply a second coat of plaster, this time using a 30 degree slope. For the second layer add a bit of texture to the plaster by using an X-shaped motion. Allow an additional 10 hours drying time. Place the third and final coat onto the surface using a 45 degree slope, filling in the spaces left by the X-shaped application. Though the space will be filled the texture will remain, leaving a smooth yet texture-rich surface.
Clean the spatula between each coat of plaster to avoid any unintentional marks to the surface.
Wear a dust mask when mixing the plaster and mortar, as inhalation of particles may be hazardous.