Historic buildings are not like modern buildings and they vary greatly from area to area and come in a diverse range of building fabrics, construction methods, styles, and level of heritage value. Traditionally constructed buildings, generally those built before 1914, are typically constructed of solid walls and permeable rendering materials such as lime mortars, allowing moisture to pass through the building. This moisture would then be driven out through drafts and the use of open fires. When looking at improving the thermal efficiency of your historic property below are three key pointers to think about before renovating your historic building;


Figure 1: Typical Edwardian terrace house in Cardiff (Zoopla, 2020)



  • Understanding – Before setting out, it’s important to understand how your building works before starting out on the project. Understanding its fabric and construction allowing for an improved understanding of what approach to take. Introducing less-intrusive insulation methods ensuring the your building is not harmed by any condensation risks.


  • Reversibility – A primary consideration should be ‘reversibility’ where possible or ‘sympathetic’ restoration when implementing any intervention on an older or traditional building. This essentially means using non’ destructive methods, and not changing or removing original fabric where possible, when interventions are implemented these must be able to be easily reversed or removed without causing any damage.


  • Permeability – Before carrying out any thermal upgrading to a historic building it is not only important to understand the likely effects on the significance but also on the performance and long-term health of its fabric. As the diagram shows below traditionally constructed buildings are characterised, and for the purposes of Part L defined, ‘by the widespread use of permeable materials which allow moisture within the building fabric to evaporate freely away’. This applies to the very fabric of the building, being that of solid brick or stone masonry external walls, earth buildings, infill panels in timber framed constructions, solid ground floors, plastering and rendering, internal and external decorative finishes.


Figure 2: Graphic of the differences in the movement of moisture in historic and modern buildings. (Historic England, 2017)


With that said, thermally upgrading your building may seem like a daunting task to undertake, but three are a wide range of products available to upgrade your home and simple low cost additions such as improving your roof and floor insulation and draft proofing can greatly improve the efficiency of your home. Additionally understanding how the building is occupied, adjusting behaviors and minimize energy demands through changing energy supplies and fuels or implementing renewable systems to reduce carbon emissions can be a viable option.


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Written by Shannon Thurlby | Sales & Marketing Manager