Protecting Facing Bricks: Tips for Aesthetic Appeal and Durability

10th Jun 2024 -

Facing bricks are known for their durability, low maintenance and attractive appearance. However, facing bricks are still susceptible to various types of damage that can compromise their structural integrity and appearance.

These exterior brick surfaces face various threats that can lead to issues like crack damage and discolouration. For this article, we explore solutions for preserving facing bricks, ensuring they retain their visual appeal for years to come.

What are facing bricks?

Facing bricks are designed specifically for exterior cladding applications. Unlike common bricks used for structural purposes, facing bricks prioritise aesthetics and durability to withstand harsh environmental conditions.

A defining characteristic is their dense, non-porous composition. Manufactured using high-quality clay and fired at high temperatures (700-1100ºC), they have a tight surface offering weather and moisture resistance. This boosts longevity and helps prevent staining or discolouration over time. 

Facing bricks are also available in an array of colours, textures and finishes, allowing you to create unique façades. From rich earth tones to vibrant hues, colour options include yellow facing bricks and red facing bricks.

The manufacturing process also prioritises dimensional accuracy and consistency. These bricks are precisely formed to maintain uniform brick sizes (215 x 102.5 x 65mm). 

Facing bricks can feature intricate patterns, textures or glazed surfaces, adding depth to the overall design. These decorative elements range from traditional brick patterns to modern and contemporary styles. 

Are facing bricks fully waterproof?

While facing bricks are resistant to weathering, they are not completely waterproof. The degree of water resistance depends on several factors. These include the brick's composition, manufacturing process and the overall wall assembly design.

Like all clay-based masonry units, facing bricks have a certain degree of porosity and water absorption. However, even high-quality-facing bricks typically have a water absorption rate ranging from 3-8%. 

While the brick itself may not readily absorb water during light rain, prolonged contact can eventually lead to water penetration. 

6 common causes of facing brick damage

Despite their durability, facing bricks are still susceptible to damage that may compromise structural integrity and aesthetic appeal. Understanding the common causes is essential for introducing effective prevention tips.

1. Moisture penetration

The main culprit is moisture infiltration. Whether it comes from excessive exposure to water, rain, humidity or groundwater, moisture may lead to several issues. Prolonged moisture absorption causes efflorescence, a white powder that forms on the brick surface as water-soluble salts crystallise.

Also, freeze-thaw cycles exacerbate the problem. Water trapped within the brick expands during freezing, creating internal pressure that leads to cracking, spalling and surface deterioration.

Solution: Proper flashing and drainage details should be introduced to direct water away from the brick surface. Plus, using a high-quality water-repellent sealer can help reduce moisture absorption.

2. Environmental factors

Facing bricks are constantly exposed to the elements, making them vulnerable to environmental factors. Temperature fluctuations, ultraviolet radiation from sunlight and exposure to air pollutants may all contribute to degradation.

High temperatures cause bricks to expand and contract, leading to cracks or warping, while UV radiation leads to fading or discolouration over time. Furthermore, acid rain and other pollutants react with the brick's components. This leads to surface etching, pitting or erosion. 

Solution: Lay bricks with appropriate material properties, such as low porosity and high compressive strength. This enhances their resistance to environmental factors. Adding shading elements or protective coatings lowers the effects of UV radiation and pollutants.

3. Mechanical stress

Facing bricks also suffer damage from mechanical stresses, such as impacts, vibrations or structural movements. The impact from falling objects or accidental collisions can result in chips, cracks or complete fracturing of the bricks.

Also, vibrations from heavy machinery and construction activities may cause a mortar joint to loosen or brick to become dislodged. Structural movements because of settling or thermal expansion create stress on the brick façade, leading to cracking or displacement.

Solution: Ensure adequate structural support, proper spacing of expansion joints and use appropriate anchoring systems. This allows movement and prevents cracking or displacement of the bricks.

4. Salt crystallisation

The presence of soluble salts, such as sulphates and chlorides, may lead to severe damage to facing bricks. These salts originate from various sources, including mortar, concrete, groundwater or even airborne pollutants. 

When moisture penetrates the bricks, it dissolves these salts and then migrates to the surface as the water evaporates. As the salts crystallise, they apply pressure within the brick pores and capillaries, leading to spalling and cracking over time.

Solution: Using materials with low salt content, such as low-alkali cement and salt-free aggregates, minimise the risk of salt crystallisation. Also, adding venting and drainage details may allow for the escape of moisture and prevent salt buildup.

5. Biological growth

In damp or shaded conditions, facing bricks are susceptible to biological growth, such as mould, mildew or algae. These organisms can thrive on the brick faces, feeding on organic matter and moisture. 

Over time, their growth can lead to discolouration, staining and even structural damage. The damage occurs when the organisms create acidic byproducts that erode the brick face.

Solution: Ensuring proper drainage and ventilation can reduce moisture accumulation, minimising biological growth. The application of biocidal coatings or regular cleaning helps prevent the growth of mould, mildew and algae.

6. Fire damage

While facing bricks are generally fire-resistant, prolonged exposure to extreme heat or direct flames cause significant damage. High temperatures may lead to spall damage, cracking or even melting of the brick's surface. This compromises both structural integrity and aesthetic appeal. Also, the rapid cooling of heated bricks after a fire can cause thermal shock, leading to further cracking and material loss.

Solution: Incorporating fire-resistant materials, such as non-combustible insulation and fire-rated barriers, to protect the brick façade in case of a fire. Proper detailing of control joints can also allow thermal movement and prevent cracking due to rapid cooling.

How to repair cracks in brick walls

Despite the above preventative measures, facing bricks may sustain damage over time. When this occurs, it is essential to address the issue promptly to prevent further deterioration. Here are some common brick repair techniques and best practices.

Repointing

A common repair technique involves repointing, which addresses cracked, crumbling or missing mortar joints. Rake out old mortar to a depth of at least 12.5mm (1/2 inch) to 19mm (3/4 inch). Any loose particles or debris should be thoroughly cleaned out before repointing. 

The new mortar should match the existing one in terms of colour, composition and strength. It is applied in layers, compacting it well into the joint to ensure a strong bond. Proper curing of the new mortar is essential to prevent shrinkage or cracking.

Brick replacement

When individual bricks crumble, crack or spall beyond repair, replacement is necessary. This involves carefully removing the damaged brick without disturbing the surrounding brickwork. A grinder or saw may be used to cut out the brick in sections. 

The new replacement brick should match the existing ones in size, colour, texture and porosity. Use the right mortar mix ratio and ensure proper bonding between the new and existing bricks. You should do this by creating a full bed joint and head joint.

Crack repair

For minor hairline cracks, epoxy injection or specialised masonry grouts can be used to fill and seal them. Wider cracks may require routing them out slightly to create a chase for the repair material to bond properly. The crack must be cleaned thoroughly before brick face repair to ensure good adhesion.

Epoxy injection brick repair filler involves drilling small holes along the crack. The epoxy resin is then injected under pressure to fill the crack from the inside out. Masonry grouts or sealants are applied directly into the crack and may require multiple coats.

Surface cleaning and restoration

Gentle cleaning methods like low-pressure water washing or mild detergent are preferred for removing surface dirt and grime. More stubborn stains or efflorescence may require chemical cleaners specifically formulated for masonry. 

Abrasive blasting techniques like sandblasting should only be used with caution. It can easily damage the brick surface if not done correctly. After cleaning, any areas of material loss or deterioration may need to be patched or resurfaced.

Consolidation and resurfacing

Where facing bricks have significant deterioration or loss of surface material, consolidation treatments help stabilise and strengthen the remaining substrate. This involves applying masonry consolidants or mineral treatments that harden the porous brick surface. 

Once consolidated, compatible repair mortars or coatings can then be applied to resurface and restore their appearance. 

Structural reinforcement

If the damage has compromised the stability of the brick wall, additional reinforcement measures should be introduced. This includes installing helical wall ties, masonry anchors or reinforcing coatings on the interior face. They provide supplemental support and prevent further cracking.

In severe cases, temporary shoring or bracing may be required during the brick wall repair process. Proper detailing of control joints and lintels over openings is also important to allow for structural movement.

Patching and resurfacing

In cases where larger areas of brickwork are damaged, patching and resurfacing techniques should be used. This involves removing the damaged sections of bricks. When removed, a compatible patching compound or brick wall crack repair mortar is applied to fill the voids. 

Once cured, the patched area can be resurfaced with a coating or render to match the appearance of other bricks. This method is effective for repairing spalled or eroded areas while maintaining a uniform appearance.

Brick staining and colouring

If the damage has caused discolouration or fading, brick staining and colouring techniques can be used to restore their appearance. This involves applying specialised stains, dyes or pigmented coatings to the brick surface. 

It can either boost or change its colour while preserving the brick’s texture and character. Proper surface preparation and using compatible products for this process are important for a long-lasting result.

Clay bricks vs facing bricks: What is the difference?

Facing and common clay bricks are made from fired clay. However, they are designed for different purposes. Their differences have significant implications for maintenance, repair and overall performance. Below, we compare these differences for you to consider.

Property	Clay Bricks	Facing Bricks
Composition and manufacturing	Made from lower-grade clays and shales. Fired at lower temperatures (around 2000°F/1100°C).	Produced from higher-quality clays. Also fired at higher temperatures (around 2200°F/1200°C).
Physical properties	Higher porosity and water absorption rate (8-12%). Lower compressive strength.	Lower porosity and water absorption rate (3-8%). Hold a higher compressive strength.
Aesthetic considerations	Rougher, more uniform appearance. Also, there are limited colour options available.	Wide range of colours, textures and finishes. Designed with aesthetics in mind.
Moisture resistance	More prone to moisture-related issues (efflorescence, spalling and freeze-thaw damage).	Better resistance to moisture and weathering. Less need for frequent repair work.
Cleaning and restoration	A rougher surface can make cleaning and restoration more challenging.	Smooth and uniform surfaces of facing bricks are generally easier to clean and restore.
Matching for repairs	Difficult to find exact matches because of limited colour and texture options.	Larger range of choices for seamless matching during repairs.

How much maintenance do facing bricks need?

Regular upkeep is still essential to preserve aesthetic appeal and durability. With a maintenance system, you prevent the risk of damage and extend the lifespan of facing brick structures. We detail 6 key maintenance techniques and recommended frequencies.

1. Cleaning

Gentle cleaning like low-pressure water washing or specialised masonry cleaners can be used to remove surface dirt and stains. Annual or semi-annual cleaning is recommended, depending on the exposure level and environmental conditions.

2. Repointing

Repointing involves removing deteriorated mortar from the joints and replacing it with fresh brick repair mortar. Inspect mortar joints annually and plan for repointing every 25-30 years or as needed with significant cracking or deterioration. 

3. Sealant renewal

Applying water-repellent sealants or coatings on the brick surface enhances water resistance and prevents moisture-related issues. Be sure to reapply sealants every 5-10 years to maintain their effectiveness.

4. Crack monitoring and repair

Inspect for cracks and address them quickly using repair methods, such as brick filler epoxy injection or masonry grouts. Conduct inspections annually and repair cracks as soon as they are identified to stop further damage.

5. Efflorescence removal

Efflorescence can be removed using specialised cleaners designed for masonry surfaces. Address efflorescence typically after prolonged exposure to moisture or when it affects the appearance of a facing brick structure.

6. Joint sealant maintenance

Inspect and replace deteriorated joint sealants around windows, doors or other openings to prevent water infiltration. You should inspect joint sealants annually and replace them as needed. Replacement is generally required every 10-15 years or sooner for significant deterioration.