Building a Sustainable Future: Retrofitting for Airtightness in Existing Homes

14 November 2023

In the pursuit of creating sustainable living spaces, retrofitting existing homes for airtightness has emerged as a crucial step toward energy efficiency and environmental responsibility. Paul Jennings, a leading expert from ALDAS, shed light on the significance of this endeavour during a seminar at the National Self-build Centre's Eco Workshop on Saturday, 11 November 2023. This article explores the key insights shared during the seminar and delves into the principles, benefits, and products associated with retrofitting buildings for airtightness.

We can begin by presenting the compelling reasons to retrofit existing homes for airtightness. The motivations range from practical concerns like reducing fuel bills and improving overall comfort to addressing health issues such as asthma and chest complaints. Additionally, improving airtightness helps combat mould and condensation, making rooms feel warmer by reducing draughts. This not only enhances the living experience but also contributes to achieving zero carbon emissions, a critical goal in our era of climate crisis. Furthermore, protecting the building fabric is paramount, to ensure longevity and sustainability of our structures.

Understanding the principles behind airtightness testing is fundamental to successful retrofitting. A systematic approach is used, wherein a calibrated door fan is strategically placed in an opening window or doorway. Air is then blown out to reduce pressure, enabling the identification of incoming draughts. Techniques such as smoke, vane anemometer, or thermographic cameras are employed to pinpoint these draughts accurately. This method ensures a comprehensive assessment, laying the foundation for effective retrofit strategies.

To create sustainable homes, we need to construct well-built and robust structures, as the need for energy-efficient design is complemented by effective ventilation systems. Interestingly, we noted that while most Edwardian and Victorian building stock is well-suited for retrofitting, structures from the 1980s onwards are often poorly built, rendering them too fragile and better suited to demolition. This underscores the urgency of addressing airtightness issues in modern construction practices to ensure the longevity of our built environment.

There are a range of products designed to achieve airtightness in existing buildings. These include:

·       Silicone Rubber Seals: These compressible seals are easily inserted into joints and sealed with airtightness tape, providing a flexible and effective solution.

·       Airtightness Paint: Specifically formulated to enhance a building's airtightness, this innovative paint contributes to sealing gaps and cracks, ensuring a comprehensive airtight barrier.

·       Closed Cell Foam: Similar to silicone seals, closed cell foam offers a pliable solution. Applied to joints and openings, it expands to create a seamless airtight seal.

·       Rubber Grommets: These versatile components are effective in sealing openings and connections, adding an extra layer of airtightness to the retrofitting process.

Later in the day Paul Rogers of Gapotape spoke about the changes to the Building Regulations Part L, which have introduced measures to improve airtightness.  Given that 80% of insulation performance is lost because of poor fitting, performance can be improved by ensuring any airgaps are omitted.  His product Gapotape is a compression tape that adheres to the edges of rigid insulation boards and expands to fill gaps between the structural elements and insulation, which is held in place through friction.

Retrofitting buildings for airtightness is a pivotal step in the journey towards sustainable living. The insights gleaned at the National Self-build Centre's Eco Workshop underscored the multifaceted benefits, from energy efficiency to improved health and comfort. By adhering to the principles of airtightness testing and employing innovative products, we have the tools to transform existing structures into resilient, airtight homes, contributing to a greener and more sustainable future.