The Building Conservation Directory 2022

150 T H E B U I L D I N G C O N S E R VAT I O N D I R E C T O R Y 2 0 2 2 C AT H E D R A L C O MM U N I C AT I O N S superior form known as antique-work is largely monochrome and consists of large- scale symmetrical designs populated by grotesque figures. Some painting schemes incorporate figurative painting. These are often religious in theme, but unlike earlier pre-Reformation examples, they are not so much devotional as didactive and moral in purpose, consisting predominantly of scenes derived from popular stories from the parables and the Old Testament. The main design is normally sandwiched between a frieze and a dado, the former sometimes decorated with scrollwork enclosing fanciful figures and carrying moral texts, crests and other devices. WHAT ARE EARTHEN SUPPORTS? These are painting substrates derived from soils with properties which allow them to be formed into cohesive structures or plasters. These are specifically selected from the inorganic soil strata underlying the topsoil and are frequently modified by the use of additives. These can include aggregates with the purely physical function of adapting soil texture; fibres such as hay, straw and animal hair, which have multiple functions such as improving insulation, increasing tensile and compressive strength, reducing weight, and reducing shrinkage and cracking on drying; oils and other vegetable extractions with functions such as increasing water resistance; and materials such as chalk, ash, blood and dung, which can act in various ways as chemical stabilisers. Although often rather dismissively described as ‘mud’ construction, the art of earth building is the result of centuries of experience and refinement in sourcing and adaptation. Vernacular earth construction traditions in the UK include those based on load-bearing compacted earth walling (as in ‘cob’ and ‘wychert’ construction); earth-based plasters and mortars applied to masonry or brick walling; and, most commonly, wattle and daub. The latter is a composite construction type consisting of load-bearing timber-framed structures spanned by non-load-bearing infill panels. These have timber armatures, often of hazel wattles or split lath woven horizontally around, bound, or otherwise fixed onto vertical staves, providing a flexible support for thick applications of earth-based ‘daub’. The daub may in turn carry one or more lime plasters or grounds. Most surviving domestic wall paintings are found in timber-framed houses, and it is common for the paintings to carry over both the timber frame and the infill panels. AN ENDANGERED TRADITION Although a large number of timber-framed buildings survive in the UK – mainly dating from the late middle-ages to the mid-18th century – many have lost their daub infill panels (often replaced by brick ‘nogging’) and very few retain the wall paintings that once adorned them. There are numerous explanations for their disappearance: although the extent of their susceptibility to deterioration can vary enormously depending on the nature of the soil used and the extent to which it has been adapted, all earthen supports have comparatively low compressive and tensile strength and are generally susceptible to deterioration under prolonged exposure to moisture. Liquid water from a leaking roof or bathroom can quickly erode earthen supports and destroy organically bound paint layers, while differential hygrothermal responses in composite structures can result in a range of conflicting and potentially destabilising behaviours. For example, environment-related volume changes in the daub support can cause stresses to painted lime plasters, eventually leading to their delamination and loss; constraints imposed on wattlework armatures by relatively static timber framing can provoke distortion and bulging, in turn causing daub and plaster to fail. Destabilisation and loss can also result when armatures become weakened by insect attack. Paintings on earthen supports are also usually more susceptible to incidental damage than other types of construction materials, particularly given their largely domestic context. The timber-framed buildings in which they are mainly found have also usually undergone substantially more – and more radical – modifications over the centuries than more recent buildings, including the insertion of chimney stacks, floors and staircases, and alterations to the position of windows and doorways. By the 18th century, vernacular timber and earth building traditions were regarded as inferior and confined to the construction of poorer dwellings. The ancient timber-framed frontages of grander houses were commonly concealed behind stone or brick façades, while internally, walls and ceilings were battened out with lath and plaster or hidden behind wainscoting. Today, most early buildings are now protected by law but the provision of practical guidance and oversight during building work is limited, and mechanisms for the prevention of unauthorised interventions are inadequate. Often owners are unaware that the requirement for listed building consent include all alterations, This bold floral scrollwork design once decorated the entire room of this house in Little Stretton, Shropshire, but now only one complete panel survives, applied onto split lath and daub panelling. Strapwork decoration at Scotson Fold, Manchester: much of the original scheme has been lost, but the remaining painting demonstrates its original vibrant colour scheme of vermilion, indigo, smalt, blue verditer and yellow ochre.