Brick Cleaning and Pressure Washing: What You Need to Know

Brick Is Tough — But Not Invincible

Brick has been a preferred building material in Jacksonville for over a century, from the historic homes of Riverside-Avondale to the newer developments in St. Augustine. It's durable, fire-resistant, and develops character with age. But "durable" doesn't mean maintenance-free, and "tough" doesn't mean you can blast it with 4,000 PSI without consequences.

Brick cleaning gone wrong looks like this: mortar joints washed out and crumbling, brick faces chipped and pitted, white efflorescence that gets worse instead of better, and a generally uneven appearance that's worse than the dirt you were trying to remove. The good news is that brick, when cleaned correctly, responds beautifully to pressure washing and can look nearly new even after decades of exposure to Northeast Florida's challenging climate.

Understanding Brick and Mortar

Brick Characteristics

Not all brick is created equal. The brick on your Jacksonville home could be one of several types, each with different hardness and cleaning requirements:

• Extruded brick (modern): Hard, dense, and relatively easy to clean at 2,000-2,500 PSI. This is what you'll find on most homes built after 1980 in Jacksonville
• Molded brick (historic): Softer and more absorbent. Common in Riverside and St. Augustine's historic district. Requires lower pressure (1,200-1,500 PSI) and gentler cleaning solutions
• Pressed brick: Very hard and smooth, often used for commercial buildings. Can handle 2,500-3,000 PSI
• Salvaged or reclaimed brick: Variable hardness and often more porous. Test in an inconspicuous area before full cleaning

Mortar Joints: The Vulnerable Point

The mortar between your bricks is significantly softer than the brick itself. Type N mortar (common in residential construction) has a compressive strength of only 750 PSI — meaning pressure washing at 2,000 PSI is literally stronger than the mortar. High pressure washes out the mortar's surface layer, creating channels that allow water penetration. Over time, this leads to mortar deterioration, loose bricks, and expensive repointing work that costs $8-15 per square foot in the Jacksonville area.

Safe Pressure Washing Technique for Brick

Pressure Settings

• Modern brick (general cleaning): 1,500-2,000 PSI with a 25° fan tip
• Historic or soft brick: 1,000-1,500 PSI with a 40° fan tip
• Stubborn stains on hard brick: Up to 2,500 PSI, but never direct the stream at mortar joints
• Brick patios and walkways: 2,000-2,500 PSI with a surface cleaner (flat surfaces can handle more pressure than vertical walls)

Critical Technique Rules

• Never aim directly at mortar joints — angle the spray at least 45 degrees from the joint line
• Maintain 12-18 inches distance from the brick surface — closer increases pressure exponentially
• Use a sweeping motion rather than holding the wand stationary — consistent, even cleaning without hot spots
• Work from top to bottom on vertical walls to prevent dirty water from streaking clean areas
• Test in an inconspicuous area first — always, without exception

Common Brick Stains and How to Remove Them

Efflorescence

That white, powdery substance on your brick is efflorescence — mineral salts left behind as water evaporates from the brick surface. In Jacksonville's humid climate, moisture constantly moves through brick walls, dissolving minerals and depositing them on the surface. Light efflorescence can often be removed with dry brushing. For heavier deposits, a dilute muriatic acid solution (1 part acid to 10 parts water) applied with a brush will dissolve the minerals. Always wet the brick thoroughly before applying acid, and rinse extensively afterward. Never spray acid solutions — apply with a brush only.

Algae and Mildew

Brick in shaded Jacksonville yards grows algae rapidly. The dark green and black streaks on north-facing brick walls are a combination of algae and mildew feeding on moisture trapped in the brick's pores. Pre-treat with a sodium hypochlorite solution (1:4 dilution), let dwell 10-15 minutes, then pressure wash at moderate pressure. The chemical treatment is essential — pressure alone removes the visible growth but leaves the root system intact, leading to regrowth in 4-8 weeks.

Rust Stains

Iron in brick or rusting metal fixtures adjacent to brick create orange-brown stains that are particularly stubborn. Standard pressure washing won't remove them. Use a commercial rust remover containing oxalic acid, applied according to product directions. Test first — some rust removers can lighten brick color. For rust from irrigation water (common when sprinklers hit brick walls), adjust the sprinkler heads and clean the stains promptly before they set permanently.

Biological Growth (Moss and Lichen)

Moss and lichen grow on brick in Jacksonville's consistently damp, shaded areas — particularly on brick fences, retaining walls, and north-facing surfaces. Remove physical growth with a plastic scraper (never metal), then treat with a biocide solution designed for masonry. Copper-based biocides are effective but can leave blue-green stains — zinc-based options are safer for the brick. After treatment, improve drainage and increase sunlight exposure to the area if possible.

Post-Cleaning Brick Maintenance

Sealing Brick

After cleaning, consider applying a penetrating sealer to your brick. A silane/siloxane sealer soaks into the brick and mortar, creating a water-repellent barrier that reduces efflorescence, prevents algae growth, and protects mortar joints from erosion. In Jacksonville's climate, a quality penetrating sealer lasts 5-7 years and costs $0.50-1.00 per square foot. Avoid film-forming sealers on exterior brick — they trap moisture and cause spalling (surface flaking) in our humid climate.

Mortar Inspection and Repointing

After cleaning, inspect all mortar joints for deterioration. Crumbling, recessed, or missing mortar should be repointed — a process that involves removing damaged mortar to a depth of 3/4 inch and replacing it with fresh mortar matched to the original color. Repointing costs $8-15 per square foot in the Jacksonville area but prevents water intrusion that can cause far more expensive structural damage.

Historic Brick: Special Considerations

Homes in St. Augustine's historic district and Jacksonville's Riverside-Avondale neighborhood require extra care with brick cleaning. Historic brick is softer, more absorbent, and more susceptible to damage. Additionally, the original mortar in pre-1940s homes is typically lime-based rather than Portland cement-based, making it extremely vulnerable to pressure washing. For historic brick, we recommend chemical-only cleaning (soft washing) with no pressure at all, followed by careful hand-scrubbing of stubborn areas. Many historic districts have preservation guidelines that restrict cleaning methods — check with your local historic preservation board before proceeding.

Professional Brick Cleaning Services

Brick cleaning requires judgment and experience that most homeowners simply don't have. Mistakes are expensive and often irreversible.

At Clean Fix Jax, we've cleaned every type of brick found in Northeast Florida, from 1800s coquina and brick in Fernandina Beach to modern brick facades in Oakleaf Plantation. Our technicians adjust pressure, solution, and technique based on your specific brick type and condition. Contact us for a free estimate, and we'll develop a cleaning plan that protects your brick while delivering outstanding results. Visit our blog for more exterior maintenance guides or our FAQ for common questions. For related masonry services, explore our handyman service.