A pressure washer cleans dust, algae and monsoon staining off an exposed brick wall quickly. Used too close or at full pressure, it cuts into soft bricks, blows out mortar joints and forces water deep into the wall. The rule is simple: lowest pressure that works, wide nozzle, and keep your distance.
Safe settings
| Setting | Use |
|---|---|
| Pressure | Start around 70 bar (about 1,000 psi). Most home pressure washers sold in India run at 100–130 bar at full power, so turn the pressure down or stand further back. |
| Nozzle | 25° or 40° fan. Never a 0° pencil jet or a rotating "turbo" nozzle on brick. |
| Distance | About 30 cm (one foot) from the wall. Move closer only if the dirt does not lift and the surface is not marking. |
| Angle | Spray at about 45° to the wall, not straight on. |
1 bar is about 14.5 psi, so 100 bar is about 1,450 psi.
Step by step
- Inspect first. Rake out a joint with a key. If the mortar crumbles, repoint before washing, or the water will wash it out.
- Protect windows, switches and outlets with plastic sheet and tape. Close windows.
- Test a hidden patch about 1 m × 1 m. Let it dry fully and check for marks, lighter patches or eroded joints.
- Wet the wall from the bottom up with a garden hose, so the bricks don't soak up dirty water.
- Wash from the top down in overlapping strokes. Keep the fan moving and never hold it on one spot.
- Avoid aiming at the joints. Sweep along the brick faces.
- Let it dry for 2–3 days before deciding if a second pass or a cleaner is needed.
When not to pressure wash
- New brickwork. Wait until the mortar is fully cured, at least a few weeks.
- Old, soft or under-burnt bricks, or walls laid in lime mortar. Use a soft brush and low-pressure hose instead.
- White salt patches (efflorescence). Water dissolves the salts and brings more to the surface. Brush them off dry instead.
- Walls with cracks, where water would go straight into the wall.
- During or just before the monsoon, when the wall won't get a chance to dry.
Stubborn stains
- Algae, moss and black monsoon staining: apply a biocide or diluted bleach solution, leave it for the time on the label, then rinse at low pressure. Protect plants below.
- Cement or mortar smears on new exposed brick: use a dilute brick acid cleaner only after the wall is wet, following the label. Rinse well. Never use acid on coloured or glazed bricks without a test patch.
- Oil and grease: a degreaser and a stiff nylon brush before washing.
Wear goggles, gloves and closed shoes with any chemical cleaner. See how to clean brick for more methods.
After cleaning: seal exposed brick
Once the wall is clean and fully dry, a breathable silane-siloxane water repellent helps exposed brick shed rain and resist algae. Choose a product that does not form a film or gloss, so moisture inside the wall can still escape. Apply it in dry weather, as the label directs.
Hire or buy?
For one wall, renting a machine or hiring a cleaning service is usually cheaper than buying. If you have a large exposed brick facade that needs cleaning every year or two, a home pressure washer with adjustable pressure pays for itself. Whichever you choose, check that the pressure can be turned down.
