A Guide to Advanced Practices for Achieving Flawless Facing Brickwork

12th Jun 2024 -

When done properly, exterior-facing brickwork provides a timeless look that lasts for decades with minimal maintenance. However, achieving flawless facing brickwork requires careful preparation and execution, from prepping facing bricks to ensuring proper installation.

This guide covers everything from mortar selection to laying patterns, jointing and quality control measures. By following advanced facing brickwork techniques, you can ensure your structure is uniform with clean lines. 

What is the importance of flawless facing brickwork?

Flawless brickwork using facing bricks is critically important for both aesthetic and structural reasons. The wall or façade is the face of the building that defines its overall appearance. Inconsistent brickwork detracts from the whole design and quality of the structure. Even minor defects like variations in joint thickness, uneven grout lines or chipped brick edges disrupt the uniform look. 

Beyond aesthetics, properly executed facing brickwork is also essential for structural integrity. The outer layer acts as the main barrier against water penetration, freeze/thaw cycles, temperature fluctuations and other environmental stressors. Defects like mortar shrinkage, poor brick spacing and insufficient expansion joints lead to crack damage, spalling, efflorescence and moisture issues.

How to choose the right brick mortar

Selecting the proper brick mortar mix ensures strong and visually appealing facing brick structures. Mortar serves as the bonding brickwork agent and must have the right properties like compressive strength, workability and water retention. The most common mortar mix ratio options include the following.

Type N

This is a common general-purpose mix consisting of 1 part Portland cement, 1 part lime and 6 parts sand. With a compressive strength of 750 pounds per square inch (psi), it is suitable for low-rise exterior load-bearing applications.

Type S

A higher-strength mix of 1 part Portland cement, ½ part lime and 4 ½ parts sand achieving 1,800 psi strength. It is recommended for high-load structures like foundations and outdoor brickwork, subject to severe freeze-thaw and moisture exposure.

Type O

A relatively soft and porous mortar consisting of 1 part Portland cement, 2 parts lime and 9 parts sand. Type O has a compressive strength of only 350 psi. It is best suited for non-load bearing and interior applications like old brick repair or tuckpointing.

Type M

A high compressive strength mortar designed for load-bearing masonry where durability is essential. The mix is 1 part Portland cement, ¼ part lime and 3 parts sand, achieving 2,500 psi strength. Type M is recommended for exterior brick veneer, high-rise construction and severe lateral load exposure.

In addition, there are some speciality mortar mixes.

• Type K: A very low strength (75 psi) mix of 1 part lime, 3 parts pozzolan and 12 parts sand used only for repointing historic masonry.
• Type L: Similar to Type M but with slightly less compressive strength at 2,000 psi. Used for load-bearing masonry veneers.

What are the advanced practices for facing brickwork?

These advanced techniques allow an elevated level of precision, durability and aesthetic appeal that distinguishes exceptional quality masonry work. Below, we cover the key advanced practices for facing brickwork. 

1. Specialised mortars and admixtures

• Latex-modified mortars bond better to substrates and have increased strength. The polymers in latex admixtures enhance plasticity, workability and overall durability.
• Introduce water repellents into mortar. They use chemicals like silanes/siloxanes to shed moisture while allowing vapour permeability. This protects against staining, efflorescence and freeze-thaw damage.
• Add mortar admixtures like potassium silicates which react with calcium hydroxide to create additional cementitious binders. As a result, it increases the bond and density of mortar joints.

2. Detailing for moisture management

• Install open head joints, vents or weep holes (small openings) at a maximum of 610mm (24") intervals. This allows any moisture infiltrating the cavity to drain out freely and enable airflow for drying.
• Incorporate proper flashing, end dams and drip edges which shed water away from the facing rather than trapping it. These details protect the wall system from moisture intrusion.
• Use mortar-dropping techniques by levelling out bed joints. This creates an unobstructed clear cavity free of mortar droppings that could obstruct weeps and cause moisture buildup.

3. Craftsmanship finishes

• Extruded mortar jointing techniques create a concave joint which provides a subtle visual detail compared to typical struck joints.
• Incorporate hit-and-miss patterns or soldier courses. They require careful planning and precise execution but provide attractive visual breaks from standard running bond patterns.
• Apply speciality finishes like burnished, beaded or v-joint tooling. These finishes compact and shape joints to highlight their dimensional quality and create texturally interesting shadows.

4. Environmental controls

• Implement cold weather practices like heated enclosures or insulated blankets. This ensures mortar can properly cure if temps drop below 4.4°C (40°F). Heated enclosures may also be used in hot weather to prevent premature drying.
• Use plastic breather meshes on scaffolding to protect new and freshly tuckpointed brickwork from wind-driven rain until it has set.
• Adjust mortar mixes based on conditions like adding accelerators in cold weather or retarders in hot conditions. This maintains ideal mortar workability during installation.

5. Extensive material testing

• Perform compressive strength, absorption, efflorescence and bond/shear testing of brick-mortar assemblies to validate compatibility and load capacities.
• Use X-ray diffraction analysis to examine mortar factors like porosity which impacts durability and weathering resistance.

6. Intricately patterned bricklaying

• Introduce patterned brickwork like herringbone or flemish bond. They require excellent planning and layout skills compared to simple running bonds.
• Lay speciality-shaped brickwork profiles like squints, cants or angles to create arched openings or sculptural features.

7 common mistakes when repointing brickwork

Repointing ageing or deteriorated brickwork is a skilled process that requires close attention to proper techniques and materials. Errors can lead to continued moisture problems, poor adhesion, cracking and other premature failures. Here, we outline some common mistakes to think about.

1. Mortar mixture incompatibility

Using modern high-strength Portland cement mortars can create a rigid, impermeable shell. It does not allow the existing softer lime-based original mortar to breathe and expel moisture, leading to spalling.

Solution: Conduct mortar analysis to match the existing mortar’s composition properly, adding limes, pozzolans and soft aggregates as needed. Adding masonry cementing materials like gypsum also helps achieve the right compressive strength compatibility.

2. Incorrect joint preparation

Failure to completely remove all existing mortar risks compromising the bond of the new pointing brickwork mortar. Using power tools may also compromise surrounding brick edges.

Solution: Use precise joint raking tools designed specifically for repointing to avoid damaging bricks. Carefully remove all loose particles with brushing and vacuuming.

3. Improper curing practices

Hot, dry weather quickly pulls moisture out of fresh pointing mortar preventing proper curing and developing full strength. Wet curing methods like hosing down new work can also introduce excess moisture.

Solution: Apply curing compounds immediately after tooling to lock in moisture for curing. Alternatively, hand-pack pointing with burlap strips that can be occasionally re-dampened.

4. Lack of expansion joints

Historic masonry often lacks adequate expansion joints. As the repointed areas expand/contract from existing walls, it can cause cracking, displacement and deterioration.

Solution: Introduce new soft joints by raking out existing ones every 15-20 feet. Install closed-cell backer rods and sealants to allow movement without impacting the repointed mortar joints.

5. Improper joint profiling

Repointing over existing joints that are too shallow or wide may result in inadequate bond area and premature mortar cracking.

Solution: Use angled joint raking tools to cut or grind and achieve an ideal depth of 2.5x the joint width. For example, 15.8mm deep for a 6.35mm joint. This exposes enough interior surface area for optimal adhesion.

6. Failing to properly clean new mortar

Smears or residue from new mortar left on the brick face causes staining and efflorescence if not fully removed.

Solution: Allow new repointing work to finish setting. Once set, use appropriate masonry acid cleaners and stiff brushing for brick face repair to remove any excess mortar.

7. Insufficient joint drainage

Failure to introduce drainage holes or vents means any water penetrating can become trapped behind the new mortar. As a result, this causes freeze-thaw damage.

Solution: At horizontal joints, create small drainage openings using plastic vent pieces, weep holes or install rope wicks. It allows cavity moisture to properly evacuate.

How much maintenance does facing brickwork need?

A benefit of quality-facing brickwork is its low-maintenance durability when properly installed. However, inspection and care are needed to boost its lifespan and keep brick walls and façades looking their best. 

Routine inspection (2 times per year)

• Carefully inspect the entire brick façade from the ground up to look for any cracks, spalling, efflorescence or staining.
• Check mortar joint condition for cracks, missing sections or deterioration which can expose bricks to moisture penetration.
• Examine control joints, flashing and sealants around windows and doors. This ensures they are still flexible and create proper pathways for water drainage.

Cleaning (Annually)

• Use a low-pressure (100 psi max) power washer and cleaning brickwork solution to gently remove dirt or pollution. 
• Never use high-pressure washing which can damage the brick face and erode the mortar joints.
• Carefully hand scrub heavily soiled areas with a soft bristle brush and suitable cleaner agents.

Repointing (Every 20-30 years)

• When routine inspection identifies widespread deterioration of existing mortar joints, repointing is required.
• Precisely cut out and rake old mortar to an appropriate depth, taking care not to damage surrounding bricks.
• Repoint using mortar that matches the existing or better in composition and compressive strength.
• Careful preparation, moisture control and tooling are critical for proper adhesion and long repair life.

Repair techniques for damaged facing brickwork

When maintenance like repointing is insufficient, there are several specialised repair methods to restore both structural integrity and appearance. The following techniques address common issues like how to repair cracks in brick walls and isolated defects.

1. Brick replacement

For spalling, severe cracking or missing units, carefully cutting out and removing the damaged bricks is needed. Ensure any corroding ties/anchors are also removed along with loose debris and existing mortar to expose a solid base. Replacement bricks that closely match the original in size, strength, porosity and colour/texture should be sourced. 

2. Crack injection repair

Dormant cracks less than 12.7mm wide can often be sealed out using epoxy brick wall crack repair injection. First, the crack must be routed out to create a reservoir, ensuring it is clean and dry. Injection ports are then installed at intervals along the length of the crack. The brick filler resin is pumped in under pressure to fill the void from one end to the other.

3. Stitching/grouting

Larger cracks may require stitching by cutting out a less advanced slot along the length. Small stainless steel or fibre-reinforced rods are installed and grouted into place to transfer loads across the crack. The slot is then repointed to conceal the repair and prevent future movement.

4. Masonry consolidation/resurfacing

For brickwork showcasing widespread spalling or deterioration, consolidation may be used to stabilise the surface. Low-viscosity consolidants like hydraulic lime or cementitious grouts are flooded into the substrate under pressure. 

Once cured, these form a hardened reinforced layer just behind the facing which is then repointed. In severe cases, the whole deteriorated brick surface may need chipping away before resurfacing can happen.

5. Structural reinforcement

In cases of major foundation settlement or cracking issues, reinforcement is likely required. Options include installing helical wall ties, attaching a veneer shelf angle, or applying a steel angle reinforcement beam. These help redistribute point loads across the façade.