Building Breathability: Why It’s Crucial for Older Buildings and How Sisalwool is the Perfect Fit

‘Breathability’ in buildings refers to a material’s ability to let moisture pass through, preventing it from getting trapped inside the structure. This concept is critical, especially in older buildings, where traditional materials were designed to work in harmony with the environment, regulating moisture naturally.

In contrast to modern, airtight construction, historic buildings were built using materials like lime, clay, and natural fibres, which allowed moisture to evaporate. The introduction of non-breathable materials in renovations often disrupts this delicate balance, leading to a host of structural and health issues.

Why Is Breathability Important in Older Buildings?

1. Prevents Damp and Rot
   Breathable materials ensure that moisture does not get trapped inside walls, preventing condensation and damp. In older buildings with solid walls, trapped moisture can lead to timber decay and masonry deterioration, weakening the structure over time.
2. Improves Indoor Air Quality
   A well-ventilated, moisture-regulating building prevents the growth of mould and mildew, which can cause respiratory problems and allergies. Older homes with non-breathable insulation often suffer from ‘sick building syndrome,’ where stale, damp air leads to an unhealthy living environment.
3. Maintains Structural Integrity
   Traditional buildings are meant to ‘breathe.’ However, modern materials like cement render or synthetic insulation are often used because they provide quick fixes for insulation and structural reinforcement. Unfortunately, these materials can trap moisture inside, causing walls to degrade from within over time. Over time, this can result in crumbling plaster, salt efflorescence, and even foundation instability.
4. Enhances Energy Efficiency
   Many assume airtightness equals energy efficiency, but in older buildings, a breathable approach is often more effective. By allowing moisture to escape naturally, breathable materials help maintain a stable indoor climate, reducing the risk of damp-related heat loss. This means less reliance on artificial heating and cooling systems, leading to lower energy consumption and a more comfortable living environment year-round. When a building can naturally regulate humidity, it requires less artificial heating and cooling, creating a comfortable indoor environment with lower energy demands.

The Downsides of Non-Breathable Retrofits

Many older buildings have suffered due to well-intentioned but misguided renovations. Common mistakes include:

• Applying Cement Renders: These trap moisture inside masonry, leading to rising damp and cracked walls.
• Using Plastic-Based Paints: These create an impermeable barrier, preventing walls from releasing moisture naturally.
• Installing Non-Breathable Insulation: Conventional insulation materials like foam boards and mineral wool may increase thermal resistance but fail to allow moisture movement, leading to condensation build-up inside walls.

Such issues often necessitate expensive repairs, undoing the very improvements the renovations aimed to achieve. For example, applying a cement render to an old stone building may initially appear to strengthen the structure, but over time, trapped moisture can cause severe damp problems, leading to costly structural damage and requiring extensive remediation.

Why Sisalwool is the Perfect Solution for Retrofitting Older Buildings

Sisalwool Natural Fibre Insulation is an ideal fit for older buildings, offering both high thermal performance and breathability. Here’s why it stands out:

• Moisture Regulation: Sisalwool allows water vapour to move freely, preventing condensation build-up and keeping walls dry.
• Thermal Comfort: Unlike conventional insulation, Sisalwool works harmoniously with traditional materials, helping maintain stable indoor temperatures without trapping heat or moisture.
• Sustainable & Natural: Made from renewable plant fibres, Sisalwool is an eco-friendly alternative to synthetic insulations, reducing environmental impact while enhancing building performance.
• Long-Lasting Protection: Because it resists moisture-related deterioration, Sisalwool extends the lifespan of a building’s structure while reducing maintenance costs.

Bringing Breathability Back to Heritage Buildings

Retrofitting older buildings requires a thoughtful approach that respects their original construction principles, incorporating breathable materials, careful moisture management, and techniques that align with traditional building methods to maintain the integrity and functionality of the structure. By choosing breathable materials like Sisalwool, homeowners, architects, and conservationists can restore the health of historic buildings while ensuring they remain energy-efficient and comfortable for future generations.

If you own or work on older properties, consider making breathability a priority. With the right materials, like Sisalwool, you can enhance the longevity, sustainability, and comfort of traditional buildings while avoiding the costly mistakes of non-breathable renovations.

Ready to future-proof your heritage building? Explore how Sisalwool can make a difference today.