The Best Methods for Cleaning Brick Safely

Written by PureSeal Services on December 15, 2025. Posted in Blog, Pressure Washing

What Is the Best Way to Clean Brick?

Brick is one of the most durable and visually appealing building materials available. It is used extensively in homes, commercial buildings, garden walls, chimneys, and boundary structures across the UK. Despite its strength and longevity, brick is not maintenance-free. Over time, it accumulates dirt, moss, algae, soot, efflorescence, and pollution staining, all of which can significantly affect its appearance and, in some cases, its long-term integrity.

The best way to clean brick depends on several factors, including the type of brick, its age, the level of contamination, and the location of the surface. A cleaning method that works well for modern exterior brickwork may be completely unsuitable for historic or soft bricks. Choosing the wrong approach can lead to surface erosion, moisture penetration, or permanent discolouration.

This guide explores brick cleaning in detail, explaining the safest and most effective methods, what to avoid, how costs compare (in pounds), and how to decide which approach is best for your situation 🧱

Understanding Brick Before Cleaning

Before deciding how to clean brick, it is essential to understand what brick actually is and why it behaves the way it does.

Brick is a porous material made from clay that has been fired at high temperatures. Its porosity allows moisture to move in and out naturally. Mortar, which holds bricks together, is usually softer and more porous than the brick itself. This balance allows walls to “breathe” and prevents trapped moisture from causing damage.

Cleaning methods that are too aggressive can disrupt this balance by:

• Removing the protective fired surface of the brick

• Weakening mortar joints

• Forcing water deep into the wall

Because of this, the best brick cleaning method is usually the gentlest effective option, rather than the fastest or most powerful.

Common Types of Brick Contamination

Different stains require different approaches. Understanding what you are cleaning helps you choose the safest method.

Each of these responds differently to cleaning, which is why there is no single universal method that suits every situation.

The Best General Principle for Cleaning Brick

The best overall approach to cleaning brick follows three key principles:

1. Start with the mildest method

2. Use minimal water pressure

3. Avoid harsh or acidic substances unless absolutely necessary

In most cases, a combination of gentle brushing, water, and patience produces the best long-term results.

Dry Brushing: The Safest Starting Point 🧹

Dry brushing is often the best initial method for cleaning brick, especially for light dirt, dust, and surface growth.

How It Works

A stiff but non-metal brush is used to loosen and remove debris from the brick surface without introducing water or chemicals.

Advantages

• Zero risk of water penetration

• No chemical reactions

• Ideal for older or softer bricks

• Inexpensive

Limitations

• Ineffective for deep staining

• Labour-intensive for large areas

Dry brushing is particularly effective for interior brick, fireplaces, and heritage buildings where moisture must be minimised.

Cleaning Brick with Water

When dry brushing is not enough, water is usually the next step. However, how water is applied makes a significant difference.

Low-Pressure Water Cleaning

Low-pressure water cleaning involves rinsing the brick using a hose or low-pressure spray.

This method allows dirt to be washed away without damaging the brick surface or mortar joints. It is often combined with brushing for better results.

Why High Pressure Is Risky 🚫

High-pressure washing is frequently seen as a quick solution, but it is rarely the best way to clean brick.

Potential problems include:

• Etching the brick surface

• Blowing out mortar joints

• Driving water deep into the wall

• Accelerating frost damage

For modern, hard-fired brick in excellent condition, controlled pressure washing may be acceptable, but it is rarely the safest or most sustainable option.

Using Mild Detergents for Brick Cleaning

For more stubborn dirt and organic growth, mild detergents can be introduced.

What “Mild” Means in Brick Cleaning

A mild detergent is:

• Neutral or near-neutral pH

• Free from acids and bleach

• Non-abrasive

These detergents help break down grease, grime, and biological matter without chemically attacking the brick.

Process Overview

1. Pre-wet the brick (reduces absorption)

2. Apply diluted detergent

3. Gently scrub with a soft or medium brush

4. Rinse thoroughly with clean water

This approach is widely considered one of the best all-round methods for domestic brick cleaning.

Efflorescence: A Special Case ⚪

Efflorescence appears as a white, powdery residue and is caused by soluble salts migrating to the surface as moisture evaporates.

Key Point

Efflorescence is not dirt. It is a moisture-related phenomenon.

Best Way to Deal with Efflorescence

In many cases, efflorescence will reduce naturally over time as the wall dries out. Aggressive cleaning often makes it worse.

Cleaning Moss and Algae from Brick 🌱

Moss and algae are common on shaded or damp brick surfaces. While they can look unsightly, removing them incorrectly can damage the brick.

Best Practice

• Start with dry brushing

• Follow with low-pressure water

• Use mild detergent only if required

Avoid scraping with metal tools, as these can scar the brick face and encourage faster regrowth by increasing surface roughness.

Interior Brick Cleaning

Interior brick, such as feature walls or fireplaces, requires a different approach.

Key Considerations

• Limited ventilation

• Risk of water damage indoors

• Soot and smoke staining

Dry brushing and minimal moisture are usually the best options. For fireplaces, repeated gentle cleaning over time is preferable to aggressive methods.

Cost Comparison of Brick Cleaning Methods (£)

Below is a general comparison of typical costs associated with different cleaning approaches. These are illustrative estimates only.

Choosing the safest method often saves money long-term by avoiding repair costs.

What to Avoid When Cleaning Brick 🚫

Some cleaning methods are widely used but should generally be avoided:

Acidic Cleaners

Acids can:

• Etch brick faces

• Dissolve mortar

• Leave permanent stains

Wire Brushes

Metal brushes damage the fired surface of bricks and should never be used on exposed brickwork.

Sealing Before Cleaning

Sealing dirty brick traps contaminants and can worsen appearance over time.

Brick Age and Cleaning Suitability

The age of the brickwork plays a major role in determining the best cleaning method.

Older bricks are usually softer and more porous, making gentle methods essential.

Is There a “Best” Single Method?

There is no single universal method that is best for all brick cleaning situations. However, the most consistently safe and effective approach is:

Gentle brushing combined with low-pressure water and mild detergent, used only where necessary.

This method:

• Preserves brick integrity

• Minimises moisture damage

• Reduces long-term maintenance issues

• Works for most common brick stains

Patience is often more effective than force when cleaning brick 😊

Long-Term Brick Maintenance Tips

Cleaning should not be a one-off event. Good maintenance reduces the need for aggressive cleaning.

Helpful Practices

• Keep gutters and drainage clear

• Trim vegetation near walls

• Address damp issues early

• Allow brick to dry naturally

Preventing contamination is always better than removing it later.

Final Thoughts 🧱

The best way to clean brick is not about speed or power, but about respecting the material. Brick has survived decades or even centuries because it was allowed to breathe and age naturally. Over-cleaning or using harsh methods can undo that durability in a matter of minutes.

By starting gently, understanding the type of contamination, and choosing methods that work with the brick rather than against it, you can achieve clean, attractive brickwork without causing long-term damage.

Seasonal Considerations for Brick Cleaning 🍂

The time of year plays an important role in how effective and safe brick cleaning will be. Brick responds differently to temperature and moisture depending on the season.

Cleaning during warmer, dry months allows brickwork to dry naturally and evenly. This reduces the risk of trapped moisture, which can lead to internal damp or surface staining. Cold weather cleaning should generally be avoided, as water can freeze inside the brick and cause cracking or spalling.

Autumn cleaning can be useful for removing organic growth before winter sets in, while spring cleaning helps address grime that has accumulated during colder months. Regardless of season, brick should never be cleaned during frost or prolonged heavy rain.

The Role of Mortar in Brick Cleaning 🧱

Mortar is often overlooked during brick cleaning, yet it is one of the most vulnerable parts of a wall. Most traditional mortar is intentionally softer than brick, allowing it to absorb movement and moisture.

Aggressive cleaning methods tend to erode mortar first, leading to:

• Gaps between bricks

• Increased water penetration

• A need for repointing

The best brick cleaning methods protect mortar by using low pressure and avoiding hard tools. If mortar begins to crumble during cleaning, the method being used is too harsh and should be stopped immediately.

Cleaning Brick on Garden Walls and Boundaries 🌿

Garden walls are exposed to constant moisture, soil contact, and plant growth, making them prone to heavy staining. However, these walls are often more delicate than house walls due to their exposure and construction.

Gentle brushing combined with light rinsing is usually sufficient for garden brickwork. Care should be taken not to saturate the base of the wall, as rising damp can worsen over time. Removing vegetation close to the wall often improves appearance without the need for intensive cleaning.

In many cases, partial cleaning produces a more natural result than attempting to make older garden walls look new.

When Brick Cleaning Reveals Underlying Issues 🔍

Cleaning brick can sometimes uncover problems that were previously hidden by dirt or staining. These may include cracks, failing mortar, or areas of moisture ingress.

This is not a disadvantage. In fact, gentle brick cleaning can act as an informal inspection process, highlighting areas that may need attention. Addressing these issues early helps prevent more expensive repairs later.

It is important not to attempt to “clean away” structural problems. Brick cleaning improves appearance but does not replace maintenance or repair.

Accepting Natural Ageing in Brickwork 🕰️

Not all discolouration is a problem. Brick naturally weathers over time, developing subtle colour variations and surface patina. This ageing is often part of a building’s character.

The best approach to brick cleaning balances cleanliness with authenticity. Removing harmful growth and excessive dirt is beneficial, but attempting to restore brick to a brand-new appearance can be unrealistic and damaging.

In many cases, the most successful brick cleaning results are those that leave the wall looking well cared for rather than artificially perfect.

Tags: Driveway cleaning, Exterior cleaning, gutter cleaning, Patio cleaning, pressure washing, Roof Cleaning, window cleaning