Can You Use Breeze Blocks for External Walls?

You might be wondering, "Can I use breeze blocks for external walls?" The short answer is yes, but there are several factors to consider that make it a more complex decision than it initially seems. Let's delve into the intricacies of using breeze blocks for external walls.

Breeze blocks, also known as cinder blocks or concrete blocks, are versatile construction materials made from concrete and aggregate. They're commonly used for internal walls, but their use in external walls is somewhat less common. So, what makes them suitable or not suitable for external walls?

Understanding Breeze Block Properties

Before we dive into the practical aspects, let's understand the properties of breeze blocks that make them a good fit for some scenarios but not others.

Breeze blocks are robust, durable, and offer excellent thermal mass, which helps regulate indoor temperatures. They also provide a good measure of sound insulation. However, they're porous, which can make them susceptible to moisture and the elements, leading to potential issues when used externally.

Moisture Permeability

Breeze blocks' porous nature means they can absorb water, which can lead to several issues. Prolonged exposure to moisture can cause freeze-thaw damage, especially in colder climates. This damage can weaken the blocks and lead to cracks or even crumbling.

Moreover, moisture absorption can create an ideal environment for mold and mildew growth. While these can be cleaned off, they can also cause health issues and further damage to the blocks if left unaddressed.

Insulation and Thermal Bridging

Breeze blocks offer reasonable thermal mass, but they lack the insulation properties of materials like foam or fiber cement. This means they can contribute to thermal bridging, where heat loss occurs through the wall structure, leading to higher energy bills and discomfort.

Unless they're part of an insulated cavity wall system or insulated comprehensively with external wall insulation, breeze blocks can make your home less energy-efficient than it could be. However, combining breeze blocks with other materials can mitigate these issues.

Using Breeze Blocks Safely and Effectively for External Walls

Based on the understanding of breeze block properties, we can establish some guidelines for their safe and effective use in external walls.

Firstly, unless you're in a very hot, dry climate, it's crucial to protect breeze blocks from direct exposure to the elements. This can be achieved by using them in combination with other materials in a cavity wall system or with render and waterproofing layers on the external face.

Cavity Wall System

A cavity wall system combines a layer of breeze blocks with an inner layer of better-insulating materials, separated by a small air-filled cavity. This traps air, providing better insulation and damping down sound transmission.

In this setup, the breeze blocks bear the structural load, while the inner layer provides additional insulation. The cavity allows any moisture that gets into the outer layer to drain away without reaching the inner layer.

Rendering and Waterproofing

Rendering over breeze blocks can enhance their appearance, provide a waterproof barrier to protect the blocks from moisture, and give you the option to paint the exterior of your home. However, it's crucial to use high-quality render specifically designed for external use.

It's also advisable to apply a waterproof membrane or paint to the breeze blocks before rendering to provide an additional barrier against moisture. This can help protect the blocks from weathering and extend their lifespan.

Cladding

Cladding over breeze blocks can provide similar benefits to rendering, protecting the blocks from moisture and allowing for better insulation. Cladding also offers more design flexibility, with a wide range of materials and styles to choose from.

Cladding systems often include ventilation gaps to allow any moisture that gets behind the cladding to escape. This can help prevent moisture buildup and the growth of mold and mildew.

Despite these precautions, it's essential to bear in mind that breeze blocks may not be the most suitable option for external walls, especially in damp or cold climates. Other materials, like bricks, concrete blocks with a lower water absorption rate, or even rendered or clad panels, might be more appropriate.

Building Codes and Regulations

Before making a final decision, always consult local building codes and regulations. These can vary significantly from one region to another, and some may restrict or prohibit the use of breeze blocks for external walls due to their moisture permeability.

Moreover, even if local regulations allow their use, they may require specific measures to protect the blocks from moisture, such as providing a drip edge or cavity tray to prevent water ingress.

If you're in any doubt about the suitability of breeze blocks for your project, it's always best to consult a professional builder or architect. They can provide advice tailored to your specific situation and ensure that your external walls comply with local regulations.

Alternatives to Breeze Blocks for External Walls

Given the potential issues with using breeze blocks for external walls, you might be wondering what alternatives are available. The following are some common alternatives to breeze blocks for external walls:

For a traditional bricks-and-mortar look, regular clay or concrete bricks are a tried-and-tested option. They're less prone to moisture issues than breeze blocks and come in a wide range of colors and styles. However, they can be more expensive and labor-intensive to install.

Concrete Blocks with Lower Water Absorption

Concrete blocks with a lower water absorption rate are another option. These are often referred to as denseaggregate blocks. They offer similar thermal mass to breeze blocks but are less porous, making them less susceptible to moisture issues.

However, they may still require rendering or cladding to enhance their appearance and provide additional protection against moisture and weathering.

Rendered or Clad Panels

Rendered or clad panels can provide a quick, cost-effective, and low-maintenance solution for external walls. They're typically made from materials like foam, fiber cement, or metal, and can be designed to mimic the appearance of traditional bricks or masonry.

These panels usually come with integrated insulation, providing better thermal performance than breeze blocks. However, they may not offer the same level of thermal mass, which can help regulate indoor temperatures.

Stone or Concrete Veneer

Stone or concrete veneer can provide a luxury look and feel to external walls. These are typically thin slices of natural stone or concrete mounted onto a framework or directly onto the wall structure.

Veneer can be more expensive than other options, and it may not provide the same level of insulation or thermal mass as other materials. However, it can enhance the curb appeal of a home and provide a durable, low-maintenance finish.

Ultimately, the best choice of material for your external walls will depend on your specific needs, budget, and regional building codes. It's essential to weigh the pros and cons of each material and, if necessary, consult with a professional to make an informed decision.

The final step in any construction project is maintenance. Regardless of the material you choose for your external walls, regular cleaning and inspection can help extend their lifespan and prevent minor issues from becoming major problems. So, while breeze blocks can be used for external walls, they're not always the best choice, and proper maintenance is crucial for any material you select.