How do I clean the exterior wall of my business?
Pollution, algae, cobwebs and calcium splashes dull a facade. A proper wash restores its original look, but a poorly adjusted pressure can dig out the mortar joints or mark the siding.
Updated
Quick answer
To clean the exterior wall of a business, wet the surface, apply a cleaner suited to the material from the bottom up, let it work for a few minutes, then rinse from the top down with a pressure washer set to the lowest pressure that works, using a wide nozzle held at least 30 cm (12 in.) from the wall. Always test on an inconspicuous spot first.
Time: Half a day for a storefront
What you need
- Pressure washer with a wide nozzle (25° or 40°) or a low-pressure wand
- Cleaner suited to the material (masonry, vinyl, aluminum), preferably biodegradable
- Long-handled soft-bristle brush
- Tarps or plastic sheeting to protect plants, doors and signs
- Safety glasses and gloves
Steps
- 1
Identify the material
Brick, stone, concrete, stucco, and vinyl or aluminum siding do not tolerate the same pressure. Repair cracked joints or crumbling bricks first.
- 2
Protect the surroundings
Cover plants, light fixtures and signs, close doors and windows, and mark off the sidewalk.
- 3
Do a test
Try the pressure and the cleaner on a spot that is not very visible. If the mortar or the surface is damaged, lower the pressure or switch to the brush.
- 4
Wet, then apply the cleaner
Wet the wall, then apply the cleaner from the bottom up to avoid streaks. Let it work for the time indicated, without letting it dry.
- 5
Rinse from the top down
Rinse by sweeping from left to right, from the top down, with the nozzle at least 30 cm (12 in.) from the wall. On lap siding, never aim the jet upward: water gets behind it.
- 6
Inspect and touch up
Let it dry and check: stubborn stains (rust, graffiti, efflorescence) need a specific product.
Mistakes to avoid
- Using a narrow nozzle (0° or 15°): it etches the brick and tears out the mortar.
- Washing in freezing weather: the water that seeps in makes brick and concrete crack.
- Using muriatic acid without training: it burns masonry and is dangerous.
- Letting detergent-laden water run into the storm drain: several municipalities prohibit it.
The best time
In Quebec, spring is ideal for removing winter residue, once the nights stay above freezing. A second wash in the fall prepares the facade for winter.
When should you call a professional?
For a tall facade, natural stone, graffiti or if you are unsure about the settings, leave the job to an equipped crew that also manages the wash water. HygiePro washes the facades and storefronts of businesses across Greater Montreal.
Frequently asked questions
What is the best cleaner for brick?
A detergent-based masonry cleaner, biodegradable, diluted according to the manufacturer. Avoid homemade acidic products: they attack the mortar.
How do you clean blackened bricks?
Bricks blackened by pollution or soot are cleaned with a masonry cleaner, a soft-bristle brush and water, ideally hot, followed by a low-pressure rinse. Deeply embedded stains need professional treatment.
Can you clean brick with vinegar?
It is not recommended: vinegar is acidic and can damage the mortar joints. Use a masonry cleaner instead.
How do you clean a very dirty exterior wall?
Apply a cleaner suited to the material, let it work, scrub the dirtiest areas with a brush, then rinse from the top down at moderate pressure. Repeat on stubborn stains rather than increasing the pressure.