Our fourth ‘Call to Action!’, drawn from submissions to the Housing Unlocked Open Call, draws attention to the carbon saving retrofitting work done by the folk at Carrig Conservation. Here are some of their findings about improving insulation practices in heritage buildings.

Energy Efficiency and Traditional Buildings

It’s estimated that 15-20% of Ireland’s buildings are traditional construction. Most were built before 1940, and while they are often beautiful buildings that contribute to our sense of place, they are also among the worst energy performers. 

Measures can be taken to improve the energy efficiency and comfort of older homes in Ireland, but it is important that the appropriate materials are used in the correct manner. Solid masonry walls, for instance, were designed to cyclically absorb and release moisture and the thickness of the walls ensured that the moisture never reached the inner surface of the wall. 

This understanding of traditional building physics must be at the heart of any retrofit project. A retrofit should start by correcting any maintenance issues and reversing previous inappropriate alterations like cement renders and drylining. It is estimated that a wet wall is 30% less thermally efficient than a dry wall so rectifying water ingress issues is priority number one.

Before an insulation strategy is designed for the thermal envelope (walls, roof, ground floor), the design team at Carrig would start by measuring or calculating the U-values of the existing building to understand how well the building is currently retaining heat. Once that baseline has been established, we always run the proposed insulation specifications through a hygrothermal risk assessment to ensure that the designs will be safe and effective. It is vital that the thermal improvements do not trap moisture or create cold spots where the heat can bypass the insulation. These assessments are particularly valuable for mitigating hygrothermal risks when insulating at rafter level, between floor joists at ground level or for insulating solid masonry walls internally or externally.

Noticeable energy efficiency and comfort gains can also be made by improving what is already there and reverting to a traditional way of living in old buildings. Many older buildings still retain their original single-glazed timber frame windows. These can be draughtproofed by qualified joiners and set to fit tightly within their casements. The joiner should also be able to advise on the feasibility of installing slimline double-glazing or secondary glazing. The repair and reintroduction of internal shutters or thermal curtains also greatly reduces heat loss through the windows at night and can be as energy efficient as new double- or triple-glazed windows.

The retrofit of existing buildings is almost always a lower carbon option than new construction simply because only a fraction of the materials are required to improve the building’s energy efficiency. And as it happens, the most suitable insulation materials for traditional buildings (e.g. sheep’s wool, woodfibre and hemp or cork insulating lime renders) are often carbon neutral. Traditional buildings are an important part of our past but they also haven an important role to play in our carbon neutral future.

More Articles