How to Clean and Seal Exterior Brick and Masonry

Brickwork serves as the resilient skin of your home, but time and weather inevitably leave their mark. Moss, efflorescence, and general grime can bury the natural beauty of your masonry while trapping moisture that eventually leads to structural spalling. A clean, properly sealed facade doesn't just look better; it prevents the internal damage that happens when water sits where it shouldn't. Restoring your brick is a process of gentle intervention rather than brute force. You aren't trying to strip the surface down to the clay; you are simply clearing the pores so the brick can breathe and applying a protective barrier that keeps liquid water out while letting internal vapor escape. When done correctly, your exterior will shed water like a fresh wax job on a car, extending the life of your mortar joints for years to come.

  1. Brush Away Loose Debris. Use a stiff natural-bristle brush to scrub away loose dirt, cobwebs, and organic matter from the surface. Avoid wire brushes, as they can leave metal fragments behind that will rust and stain the brick.
  2. Activate the Cleaner. Wet the wall lightly with a garden hose, then spray on a dedicated masonry or brick cleaner. Let it dwell for five to ten minutes, but do not let it dry completely on the brick.
  3. Attack the Stains. Use a long-handled scrub brush to agitate the cleaner into the mortar joints and textured brick faces. Work in manageable sections of about four feet by four feet.
  4. Wash Away All Soap. Rinse the wall from top to bottom using a standard garden hose with a spray nozzle. Ensure all soap residue is removed, as left-over chemicals can interfere with the sealant bond.
  5. Wait for Bone-Dry Brick. Allow the brick and mortar to dry completely for at least 48 hours. Sealing damp masonry will trap moisture inside, causing the sealer to fail or the brick to spall.
  6. Spray Two Protective Coats. Use a low-pressure pump sprayer to apply a silane-siloxane sealer, working horizontally. Apply two wet-on-wet coats, meaning the second coat is applied before the first has dried.