Thermographic detection of hidden archaeological features in a Cheshire thatched cottage, and related aspects of thermal performance : case study at Roadside Cottage

Thermography can be an important tool for professionals working with traditional buildings. It is recognised by Historic England as providing information on a variety of structural features within buildings. Infrared thermography (IRT) is an acknowledged retrofit tool for reducing carbon emissions from traditional buildings. The paper explores the potential application of thermography as a tool for detecting infrared images emitted by the internal plaster surface of a timber-framed thatched cottage, dating from the 15th/16th century to 20th century. The thermal irregularities from hidden timber features or structural renovations under the thatch can help improve understanding of the evolution of the building and establish the extent of surviving historical fabrics. The images from IRT investigations conducted under different temperature difference conditions in 2010 and 2012 have been compared against the features exposed when re-thatching the property and upgrading insulation levels in 2019. A follow-up survey was carried out in 2021. Related aspects of the thermal performance of the thatched envelope and the effect on internal temperature distribution have also been investigated. The IRT investigations at Roadside Cottage demonstrated the importance of maintaining sufficiently large temperature differences across thatched roof buildings to permit detection of thermal irregularities arising from hidden timber features