A review of thermal and hygrothermal requirements in historic churches

Upgrading the building fabric of historic churches is challenging due, in part, to decorative finishes, important religious artefacts and the desire to preserve cultural heritage. Historic building fabric exhibits natural control of temperature and humidity cycles. However, churches are unique in having sporadic usage patterns. This paper reviews the state of the art from current literature, aiming to establish the thermal and hygrothermal requirements of historic churches. Main observations from the literature are that 1) each component of the church has unique thermal and hygrothermal requirements, 2) artefacts have become accustomed to the established indoor climate of the church, 3) retrofit insulation may cause moisture accumulation, 4) moisture plays a significant role in the degradation of permeable building fabric. These observations are discussed with the conclusion that stabilising temperature and relative humidity fluctuations could prove beneficial for artefacts and building fabric components.