Upgrading Thermal Elements: Installing Insulation

There are many ways to improve the energy efficiency and climate resilience of a historic building or building of traditional construction . However, the need or opportunity to do so will vary widely depending on the specific context. To make sure a building is resilient, well adapted and able to provide a healthy internal environment in our changing climate, it is best to consider all proposals in a holistic manner at an early stage and throughout the project.

Considerations before adding insulation

Adding insulation to a historic building may reduce heat loss, but thought and care are needed to make sure the works are technically sound and effective and do not unacceptably alter the building's character or appearance.

It will not always be reasonably practicable or desirable to add insulation. Ill-conceived work may cause long-term deterioration to the building fabric, impact the internal environment or harm the occupants' health and wellbeing. To avoid this, the following should be considered at an early stage:

Whole building approach

To improve the energy efficiency and climate resilience of a historic building, we must both reduce emissions (mitigation) and adapt to the already changing climate (adaptation). A whole building approach is a systematic process for devising and implementing suitable, coordinated, balanced and well-integrated solutions that avoid harm to the significance of a building.

Energy Efficiency Hierarchy

Interventions should address the energy and thermal efficiency of the building as a whole, striking a balance between energy demand and building conservation. Measures should be implemented in order of priority, set out by the Energy Efficiency Hierarchy.

Properties of traditional building construction

Before deciding whether to install insulation, it is important to understand the beneficial properties of traditional building construction. These can help moderate internal fluctuations in humidity and temperature, providing and maintaining a healthy, comfortable and more stable indoor environment without harming the building fabric or occupants.

Risks of energy efficiency interventions

Adding insulation to historic floors, roofs and walls can reduce heat loss, but inappropriate retrofit works may increase the risk of unintended consequences (causing harm to the significance of the building, its fabric or its occupants) or maladaptation (undermining the building's performance and resilience to climate change).

Building Regulations and energy efficiency

When considering the upgrade of thermal elements, such as installing insulation in an existing building, Building Regulations requirements may apply. Relevant Approved Documents provide guidance on how these regulations could be applied to historic buildings.

Designation and significance of the building

Interventions may impact a historic building's significance and so must be carefully considered and balanced against demonstrable benefit. A Statement of Heritage Significance and a Heritage Impact Assessment can help decide the best way to accommodate change to heritage assets, and also establish which, if any, interventions are justifiable, accounting for a building's designation and significance.

Links to detailed guidance

Related research

Moisture properties of insulation materials and their applicability to traditional construction.

This Sustainable Traditional Buildings Alliance (STBA) report provides detailed technical guidance on moisture properties and movement mechanisms, enabling professionals and practitioners to make better informed decisions when specifying and installing insulation systems in a traditional building. It is authored by University College London and funded jointly by Historic England, Historic Environment Scotland and Cadw, in partnership with the Department for Communities (Northern Ireland).