Building Material Breathability Experiment: Surprise Result Revealed!

The Building Material Breathability Experiment

Mixes From our test

• 3.1 Sand and Cement
• 5.1 Sand and Cement
• 6.1.1 Sand, Cement and Hydrated Lime
• 3.1 Natural Hydraulic Lime (NHL)
• 5.1 Natural Hydraulic Lime (NHL)
• Dryzone Hi-Lime
• Rapid Set Plaster
• 6.1.1 with Skim

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Material Breathability

The term “breathability” in the context of building materials refers to their ability to permit the passage of moisture vapor through them without allowing liquid water to penetrate. This feature is essential because it ensures that the materials can manage moisture levels effectively, which is vital for both the structural integrity of buildings and the health of the indoor environment.

The Importance of Breathable Materials

In everyday building use, a significant amount of moisture is produced from routine activities such as cooking, bathing, and even breathing. Each of these activities generates water vapor that can accumulate indoors if not properly managed. Breathable materials play a critical role in addressing this challenge by allowing this moisture to pass through the walls and escape into the external environment. This process, known as vapor permeability, helps prevent the buildup of dampness inside the building.

Health Benefits of Good Material Breathability

The ability of building materials to manage moisture effectively has direct implications for indoor air quality and the health of the occupants. When moisture accumulates within a building, it creates an ideal environment for the growth of mold and mildew. These fungi not only cause unsightly stains and unpleasant odors but can also have serious health implications. Mold spores can trigger allergic reactions and respiratory problems, especially in sensitive individuals such as children, the elderly, and those with pre-existing health conditions. By using breathable materials, the risk of mold growth is significantly reduced, contributing to a healthier indoor environment.

Structural Advantages

In addition to health benefits, good material breathability is crucial for maintaining the longevity and durability of the building structure itself. Moisture trapped within walls can lead to a range of problems, including wood rot, corrosion of metal components, and degradation of insulation materials. Over time, these issues can compromise the structural integrity of the building, leading to costly repairs and potential safety hazards. Breathable materials help to prevent these issues by allowing moisture to evaporate away, thus protecting the structural elements of the building from moisture-related damage.

Common Breathable Materials

1. Lime-based Mortar and Plaster: Unlike standard cement, lime is highly breathable and can accommodate fluctuations in humidity by absorbing and releasing moisture.

This makes lime-based products excellent for use in older buildings, where flexibility and breathability are essential to withstand natural settling and movement over time without cracking.

2. Natural Hydraulic Lime (NHL): NHL is preferred in restoration and conservation projects for its moderate set time and high breathability.

It works well in damp environments, providing durability without sacrificing the traditional aesthetic of historic buildings.

3. Clay Plaster: Clay is another highly breathable material with excellent moisture regulation.

It helps create a healthy indoor climate by buffering moisture levels and purifying the air, which makes it ideal for eco-friendly constructions.

4. Gypsum Plaster: While gypsum plaster is less breathable than lime or clay, it provides some moisture permeability, which is often sufficient for modern construction needs. It’s also fast-setting, making it a popular choice for quick renovations.

Measuring Material Breathability

Material breathability is often measured by their permeance, commonly referred to as the “perms” rating.

This measurement indicates how much moisture vapour can pass through a material. The higher the perms value, the more breathable the material.

Choosing the Right Material

Selecting the right breathable material depends on several factors, including the climate, the building’s existing materials, and the space’s specific needs.

For instance, more breathable materials might be necessary in areas with high humidity to manage indoor moisture effectively.

The Impact of Breathability on Building Longevity

Using breathable materials can significantly impact a building’s longevity. Allowing walls to dry out naturally prevents structural damage caused by trapped moisture, such as rot and deterioration of building fabric. This not only ensures the structural integrity of the building but also maintains its aesthetic and functional value over time.

 

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