Best Practices for Power Washing Brick and Mortar Surfaces

Brick exteriors bring a timeless charm and rustic beauty to homes, patios, and walkways. But over time, even the most durable masonry surfaces collect grime, mold, algae, soot, and stains that dull their appearance. That’s where power washing comes in — but proceed with caution! ⚠️💦

Brick may be tough, but it’s also porous and prone to damage if you use too much pressure or the wrong technique. In this guide, we’ll cover the best practices for safely and effectively power washing brick and mortar surfaces so you can restore their natural beauty without causing long-term damage.

Let’s scrub in! 🧼🧽

🧠 Understanding Brick and Mortar

Before you fire up the power washer, it’s important to understand what you’re working with:

Brick is porous and absorbs moisture, especially older or handmade bricks.
Mortar joints (the material between bricks) are softer and can deteriorate under high pressure.
Over time, exposure to the elements can weaken both — especially when power washing is done incorrectly.

So while power washing can clean brick effectively, it must be done with the right equipment and methods.

✅ When to Power Wash Brick

Power washing is great for removing:

Mold and mildew 🌿
Moss and algae
Dirt and pollution stains
Paint flakes (for repainting or restoration)
Efflorescence (white mineral streaks)

But avoid power washing if your brick:

Is crumbling or flaking (known as spalling)
Has large cracks in the mortar
Is more than 100 years old — historical bricks can be fragile

💡 If your brick is damaged or historic, consult a masonry restoration expert before cleaning.

🧼 Best Practices for Power Washing Brick

✅ 1. Use a Low-Pressure Setting

The #1 rule: Don’t blast it.

Use a pressure washer with:

500–1,200 PSI max
A 25- or 40-degree nozzle (green or white tip)
At least 12 inches of space between the nozzle and surface

High pressure can:

Erode mortar
Chip brick edges
Force water deep into pores, leading to mildew later

🚿 Always start with the lowest pressure and work your way up only if necessary.

✅ 2. Pre-Wet the Surface

Before applying detergent or pressure:

Soak the brick with water to prevent absorption of chemicals
This also helps loosen surface debris for easier cleaning

Use a garden hose or a light rinse from the washer with no detergent.

💧 Never apply detergent to dry brick — it increases the chance of discoloration.

✅ 3. Use Brick-Safe Cleaning Solutions

Choose a cleaner specifically designed for masonry or brick. Avoid:

Bleach-heavy mixes
Harsh acids like muriatic acid (unless properly diluted and used by pros)

✅ 4. Work in Sections from Bottom to Top

To avoid streaking:

Clean from bottom to top (yes, it feels backwards!)
Rinse top to bottom

Why? Water from above can run down and leave streaks on areas you haven’t cleaned yet.

🧽 Scrub extra-dirty spots with a soft brush or broom after soaking.

✅ 5. Rinse Thoroughly — But Gently

Once the cleaner has loosened the grime:

Use a low-pressure rinse (25–40° tip)
Keep a steady 12–18″ distance
Avoid directing water into mortar joints at sharp angles

💡 Rinse in overlapping motions to ensure even cleaning.

❄️ Seasonal Considerations

Brick absorbs moisture, so:

Don’t power wash in freezing temperatures
Avoid rainy days when brick is already saturated
Let the surface dry for 48–72 hours post-wash if you plan to seal it

🧰 Tools and Gear Checklist

✅ Pressure washer (500–1,200 PSI)
✅ 25° or 40° spray tip
✅ Pump sprayer (for detergent)
✅ Brick-safe cleaning solution
✅ Soft bristle brush
✅ Safety goggles and gloves 🧤🕶️
✅ Waterproof boots and clothing (you will get wet!)

🧱 Optional: Masonry sealer to apply after cleaning for long-term protection.

❓ Should You Seal Brick After Washing?

Sealing is not required, but can help:

Prevent water intrusion and efflorescence
Reduce mold and mildew buildup
Maintain a cleaner appearance for longer

Only seal after the brick has completely dried for at least 48–72 hours.

Choose a breathable masonry sealer that allows moisture to escape — avoid high-gloss products that trap water.

🧑‍🔧 DIY vs. Professional Help

DIY is fine if:

Your brick is in good condition
You’re using appropriate pressure
You’ve done your research 🧠

Call a pro if:

Your brick is fragile, historic, or spalling
Mortar is cracked or loose
You’re unsure about equipment settings or cleaners

Hiring a professional power washing company ensures safe results — and most come with insurance, so you’re covered. 👍

✅ Final Thoughts

Brick surfaces are beautiful, durable, and long-lasting — but only if treated with care. Power washing brick the wrong way can lead to costly repairs, but with the right technique, you can restore your masonry to like-new condition.

🧱 Key reminders:

Use low pressure
Pre-wet and pre-treat with masonry-safe detergent
Clean bottom to top, rinse top to bottom
Avoid sharp angles and blasting mortar joints

Treat your brick gently and it’ll stay strong and stunning for decades. 💪🧼