What’s Better – Repointing Brickwork or Rendering Your Walls?

When maintaining and improving a property’s exterior, homeowners can choose between repointing brickwork and rendering walls. Both options have merits, but the best choice depends on several factors, including the condition of the walls, the desired appearance, and the building’s location.

Repointing brickwork is a crucial maintenance task that involves updating the mortar joints between bricks. Over time, exposure to weather conditions can erode or damage these joints, leading to structural and aesthetic issues if not addressed. The process of repointing not only restores the visual appeal of brick masonry but also reinforces the structural integrity of the building.

One of the most critical aspects of repointing is selecting the correct mortar type. The new mortar must match the physical properties and colour of the original as closely as possible. This is especially important in older or historic buildings where maintaining the original appearance is essential. Using too hard or too soft mortar compared to the surrounding masonry can cause further damage over time. Harder mortar can lead to cracking in the bricks themselves, while a softer one might erode more quickly.

Repointing process

The repointing process begins with carefully removing the old, damaged mortar. This is typically done using hand tools such as chisels and hammers to avoid damaging the bricks. The depth to which the old mortar is removed is critical; usually, it is about twice the width of the joint, but it can vary based on the masonry condition.

Once the old mortar is removed, the joints are cleaned to ensure a solid bonding surface for the new mortar. This cleaning process often involves brushing and sometimes flushing the joints with water, which helps remove any residual dust or debris.

Following the preparation, the new mortar is carefully applied. This involves packing the mortar tightly into the joints and ensuring no air pockets or gaps. The technique used to apply mortar is crucial, as it affects the longevity and effectiveness of the repointing. After the mortar is in place, it is typically finished to match the style of the original pointing. This might involve shaping the mortar to a specific profile, such as rounded or recessed.

Properly executed repointing can significantly extend the life of a brick structure. Sealing the joints from water ingress prevents frost damage and salt deposition, which can lead to spalling and cracking of the bricks. Furthermore, repointing can enhance a building’s thermal efficiency by eliminating drafts that pass through deteriorated mortar joints.

Pros of repointing brickwork

Preservation of architectural character

One of the foremost advantages of repointing is its ability to preserve a building’s original architectural character. For historic or older buildings, maintaining the authenticity of the exterior is crucial not only for aesthetic reasons but also for heritage conservation. Repointing allows the building to retain its historical integrity by using materials and techniques that match the original construction as closely as possible. This is particularly important in conservation areas or listed buildings where alterations are subject to strict regulations.

Structural integrity

Repointing brickwork significantly enhances the structural stability of buildings. Mortar plays a crucial role in the masonry structure, acting as a bonding agent that holds bricks together. Over time, mortar can deteriorate due to weathering and environmental stresses. This leads to weakened walls susceptible to moisture penetration and subsequent damage such as frost action and salt crystallisation. By replacing old, crumbling mortar with new, robust mortar, repointing helps reinforce the wall’s strength, ensuring it remains sound and secure.

Weather resistance

Properly executed repointing of brickwork effectively seals the mortar joints, making them impervious to adverse weather conditions. This is particularly beneficial in climates where freeze-thaw cycles are common, as it prevents water from entering the joints and causing damage through freezing. The right mortar mix can also resist the erosive effects of rain and wind, thereby prolonging the façade’s durability and reducing the likelihood of moisture-related issues such as mould growth and interior dampness.

Increased Energy Efficiency

Another significant benefit of repointing is improving a building’s thermal performance. Old, deteriorating mortar joints can become pathways for air leakage, leading to increased energy consumption for heating or cooling the interiors. By sealing these gaps, repointing reduces draughts and improves the insulation properties of the walls. This makes the indoor environment more comfortable and reduces energy bills, making it a cost-effective improvement in the long run.

Cons of repointing brickwork

Cost

Repointing can be costly, especially when dealing with large or complex structures. The cost can increase significantly if the building is historic and requires specific traditional techniques or materials to maintain its authenticity. Additionally, the accessibility of the wall, the condition of the existing mortar, and the need for scaffolding can all add to the overall expense. For many property owners, these costs need to be weighed against the long-term benefits of repointing.

Time-consuming

Repointing is labour-intensive and time-consuming. Each step, from removing old mortar to carefully filling in joints with new mortar, must be done with precision and care to avoid damaging the bricks. The project can take several weeks or even months for large buildings to complete. During this period, parts of the property may be inaccessible, and the appearance of scaffolding can be visually disruptive. This extended timeframe can be inconvenient and may temporarily affect the day-to-day activities of residential or commercial buildings.

Specialist skills

Repointing requires more than just basic construction skills; it demands an understanding of historic masonry techniques, especially when dealing with older buildings. Finding the right professionals with the skills and knowledge to match old mortar in composition, colour, and texture can be challenging. Incorrect repointing can lead to further deterioration of the structure. For example, using a mortar harder than the original can cause bricks to crack. On the other hand, a softer mortar might erode prematurely, leading to a need for more frequent repairs.

Inaccurate matching

Achieving an exact match with the existing mortar and brickwork can be difficult, particularly with older or weathered buildings where the original materials are unavailable. If the new mortar does not match the physical properties or colour of the original, it can lead to aesthetic inconsistencies that detract from the building’s visual appeal. Moreover, improper matching can affect the physical performance of the mortar, potentially leading to issues like accelerated wear or inadequate bonding, which can compromise the wall’s integrity.

Risk of uncovering additional problems

Other structural issues, such as hidden cracks, damaged bricks, or internal dampness, may be uncovered during the repointing process. While it’s beneficial to identify and address these issues early, the additional repairs can unexpectedly increase the project’s scope and cost.

Is rendering walls the better choice?

Rendering the exterior walls of a building involves applying a coat of plaster or cement, which can be both decorative and protective. This technique has been used for centuries to improve exterior walls’ appearance and offer protection against the elements. Modern rendering can involve a variety of materials, each providing unique benefits and challenges.

Types of rendering

• Cement Rendering is one of the most common forms of rendering. It uses a mixture of sand, cement, and sometimes lime to create a durable layer. After application, it can be textured, smoothed, and painted to match any desired aesthetic.
• Acrylic Rendering involves adding acrylic resins to the cement mixture, enhancing its strength and flexibility. It is more cracking-resistant than traditional cement render and can be applied in thinner layers. Acrylic render also comes pre-coloured, eliminating the need for painting.
• Silicone Render is known for its superior water resistance and breathability. Silicone render is ideal for enhancing insulation and preventing dampness. It also maintains its colour and finishes longer, reducing maintenance needs.
• Lime Render is often used to restore older buildings. It allows for greater breathability, preventing moisture from trapped within the walls—a common issue in older constructions.

Advantages of rendering over repointing brickwork

1. Enhanced aesthetics: Rendering can dramatically transform a building’s exterior appearance. It provides a clean, uniform look that can be customised with different textures and colours. This is particularly beneficial for properties with mismatched or damaged brickwork, as rendering offers a way to unify the facade without extensive reconstruction.
2. Increased protection: Render acts as an additional layer of skin for a building. It offers protection against weathering and environmental damage, including issues like rain penetration and frost damage. This protective layer can extend the life of the underlying structures by shielding them from direct exposure to harmful elements.
3. Improved insulation: Certain types of rendering, such as insulated rendering systems, can significantly enhance a building’s thermal efficiency. These systems include an insulation board fixed to the wall before the render is applied, which can help reduce heating costs and improve comfort inside the building.
4. Maintenance and durability: Modern renders, especially those with silicone or acrylic bases, are designed to be low-maintenance. They resist algae growth and fading and do not need to be painted as frequently as traditional finishes.