Older brick walls have a lot of charm. If they are neglected, however, dinginess, staining, fading and disrepair can ensue. Regularly clean your brick walls to ensure they remain contaminant-free and repair mortar joints as soon as you see crumbling to maintain the wall's structural integrity.
Remove any loose or crumbling mortar, using a chisel and a hammer or a rotary tool with a grout removal bit.
Rinse the brick wall with water to dampen it.
Wash the brick wall with a phosphoric acid cleaner (while the wall is still wet) for a deep and thorough cleaning. Dilute the cleaner as instructed in the manufacturer's instructions. Scrub the bricks with the solution, using a scrub brush. Work in small sections at a time and rinse the cleaner with fresh water as you go. Do not let the cleaner remain on the wall for more than five minutes and do not let the cleaner dry on the wall.
Make a mortar mix for filling and repairing the areas where you removed damaged mortar. Use dry mortar pre-mix or create your own mortar mix with three parts sand and 1 1/2 part cement. Add water gradually to the dry material while stirring until you create a thick paste. Add 1/2 cup latex binder for every 1 0.227kg. of dry mortar material.
Dampen an area to be patched with a wet paintbrush.
Force mortar into the hollowed cavities, using a point trowel.
Mist the fresh mortar patches periodically with a spray bottle to keep them slightly damp and to ensure consistent, gradual curing.
Smooth down the mortar patches to create a finished seam at the point when the mortar starts to harden, using a jointer tool.
Cover the areas with plastic for two to three days and continue to spray the patched areas with water to further ensure proper curing. If the patches cure too fast, they may crack.
Add a finish to your brick wall, if desired. Paint the wall with an epoxy-based sealer and a paintbrush to add a semi-glossy coat to the bricks and to prevent surface corrosion and masonry dust from occurring. Brick stains are also available if you want to enrich or even change the colour of your bricks.
Wear latex gloves to avoid skin irritation while working with phosphoric acid cleaner.