Within the context of historic architecture the term ‘vernacular’ is primarily used to describe buildings that have been constructed from materials that have usually been sourced from the locality in which the building is situated. Historically, this has meant the use of local stone, clay, timber, earth and straw to construct the walls and roofs of mainly farm buildings, cottages and other small domestic dwellings. However, as post-medieval vernacular traditions developed, other materials were used in different areas of the construction process and often for much larger buildings. The use of such materials, and the practices that accompanied them, have a long and complex history that is bound up with the social, cultural and economic traditions of different counties and their regional variations.
During the late 16th and early 17th centuries, throughout the English Midlands, a practice developed of using local gypsum and lime for mainly first and second floor flooring in a variety of vernacular buildings, as well as the much larger houses of the landed gentry. In 1611, John Speed published his Theatre of the Empire of Great Britaine, which explored the cultural, geological and topographical differences in each of England’s great counties. In Nottinghamshire, he describes the use of a ‘new’ building material that had found many uses. “Therein groweth a stone softer than Alabaster, but being burnt maketh a Plaister harder than that of Paris; wherewith they flower their upper rooms; for betwixt the joyists they lay only long bulrushes, and thereon spread this Plaister, which being throughly dire becomes most solide and hard, so that it seemeth rather to be firmestone than mortar, and is troad upon without all danger.” ♥
This ‘new’ material wasn’t really that new in the sense that it had been used for countless applications in other periods to serve both similar and different purposes. The use of earthen materials such as chalk, clay, lime and other types of binders had been used to create agricultural and domestic floors in buildings for centuries. Norman builders were known to use similar materials and methods to create the floors in their buildings. However, by the late 16th Century, in the English Midlands, the practice had matured to a reasonably sophisticated level with the materials being specifically selected for the purpose.
In the 17th century, John Speed’s identification of gypsum plaster floors in Nottinghamshire would not have been an isolated instance, as flooring of this type could have been found in many of the counties that make up the English Midlands. From as far north as Derbyshire and Lincolnshire to the more southern reaches of Warwickshire and Worcestershire and most counties in between, the use of both gypsum (calcium sulphate) and lime (calcium hydroxide) as the main constituent component of domestic flooring was reasonably common.
An historic plaster floor with signs of repair (note the difference in colour).
The main ‘ingredient’ or binder needed to create the floors was burnt gypsum, which was created by ‘burning off’ lumps of gypsum rock at its source using large fires of wood and coal, a process John Farey perceived as extremely wasteful. Writing in his General View of the Agriculture and Minerals of Derbyshire (1813) he states “…the process of burning and preparing plaster for floors … is the most wasteful one that can be imagined: an immense pile of brush and billet wood was made, and upon it the old plaster and some new … was laid, and fired: after which, a number of men with flails, thrashed, and rather wasted and spread it about than pulverised it”.♦ After the gypsum had been fired it would be broken down into a powder and mixed with water to create the coarse binder used in the mix.
The floors, which typically ranged in thicknesses from 50mm – 100mm, consisted of a gypsum or lime based screed mix that was laid onto a suspended timber structure, or in some instances, directly onto the earth at ground level. At first and second floor level, where the mix would have been poured and spread directly onto a timber structure, various forms of straw or reed bedding would have been used to support the mix through its drying phase (resembling a crude form of shuttering). It is thought that most of the floors that were laid directly onto the earth would have perished over time due to the soluble properties of gypsum, however, some still remain in isolated locations, such as Lichfield Cathedral, where lime was more prevalent and modern building development hasn’t yet intervened.
Detail of straw bedding underneath a plaster floor in Derbyshire.
It is clear from research conducted over the last couple of decades that the use of gypsum and lime for the construction of floors varied from county to county, which was obviously linked to the readiness and availability of the materials. Earthen and plaster floors of this type were made from a number of elements that shared similar properties and capacities, such as reed, straw, clay, unburnt coal, crushed stone and brick and kiln ash (which probably acted as a type of pozzolan) but the binding ingredient was usually gypsum or lime (or a mixture of both). Some floors have even been found to contain oats and barley chaff, as in the Manor House in Bramcote, Nottingham.♣ The former Building Research Station, found that when analysing the floors at Old Hardwick Hall in Derbyshire (completed in 1597) that lime had been the main component, whereas at ‘nearby’ Bolsover Castle (completed in around 1620), the use of gypsum was identified as more dominant. ♣ This analysis also corresponds strongly with a statement attributed to Bess of Hardwick (Lady of the Manor at both Chatsworth and Hardwick) in 1556, in which, during a recorded consultation with her steward at Chatsworth regarding the specification for flooring, she states “cause the floor in my bedchamber to made even with either plaster, clay or lime.” ♣ The upper floors at Hardwick Hall were shown to contain red brick and local stone, as well as the lime binder. ♠
Floors made of this material were both necessary and desirable for a number of reasons, they offered a draught-free surface that was warm under foot with reasonably good sound insulation, as well as providing relatively substantial fire protection to living and sleeping spaces (this is perhaps why they are still often found in loft and attic spaces). They were also thought to have helped with reducing the amount of vermin within households, which is probably why Nicholson (a 19th century researcher), describes their use in Derbyshire as much used ‘for laying the floors of cheese rooms and granaries’.♦ The benefits of these floors had wide ranging appeal, so much so, they were still being constructed (in the English Midlands at least) well into the 19th century.
Detail of a plaster floor in the process of repair near the Staffordshire border.
Due to the range of materials used in the process of constructing these types of floors, the terminology that was historically used to describe them has changed over time. As Bess of Hardwick’s quote above indicates, there was at least some common knowledge of the ingredients that were used, which perhaps offers some hints towards why such a myriad of terms to describe them still exists. Historically, they were often just referred to as ‘plaster’ floors, however, we now use (sometimes incorrectly) more specific terms, such as ‘reed and plaster’, ‘lime plaster’, ‘lath and plaster’, ‘lime-ash’ and even ‘limecrete’, which is perhaps due to the textural similarities with its more modern Portland equivalent. However, at least in the Midlands, gypsum, due to its abundance and accessibility (gypsum can be found in most parts of England, but the Midlands contains significantly large deposits), was often the most dominant ingredient used in the construction of these types of floors, with lime being used significantly less, comparatively.
Cracks and fissures in plaster floors are extremely common.
Over the last two or three decades, with the advent of modern building development, many of these floors have been lost or damaged due mainly in part to a lack of knowledge regarding their composition and history. They can often provide an extremely un-level surface that seems at odds with our need for creating relatively modern interiors within the context of historic structures. Given the individual nature of their composition, they can often appear difficult to repair and many suffer from significant cracks or fissures, which is a reasonably common feature due their tendency to follow the line of constantly shifting timbers. Even the floors at Hardwick Hall (one of Derbyshire’s greatest country houses) bear the scars of many centuries of pounding footsteps and structural movement!
A gypsum plaster floor identified during a routine building survey in Derbyshire.
As our knowledge of the construction of these types of floors develops and the desire to retain the unique character they provide slowly increases, the more significant their presence will be in enabling us to truly understand how our regional vernacular traditions developed over the centuries before the Industrial Revolution took hold. The English Midlands witnessed many changes through those centuries, it would be a genuine shame to lose the material fabrics that provide the historical evidence of those changes, as well as a unique ‘window’ onto how we once lived.
♱ This article is dedicated to the late Anthony Goode, whose tireless work and unbounded curiosity provided a significant development in our identification, understanding and long-term conservation of gypsum and lime floors throughout the English Midlands.
♦ SPAB (Society for the Protection of Ancient Buildings), 2018, Gypsum Plaster Floors, Regional Technical Advice Note. (This advice note was authored by Anthony Goode DipBldgCons (RICS), IHBC).
♥ Quoted in The Pattern of English Building by Alec Clifton-Taylor, Faber & Faber, 1972, p. 352.
♣ Watt, D. & Colston, B., 2002, Analysis of Historic Lime and Gypsum Plaster Floors—Part One, Journal of Architectural Conservation, 8:1, 57-73.
♠ Watt, D., Colston, B. & Goode, A., 2002, Analysis of Historic Lime and Gypsum Plaster Floors—Part Two, Journal of Architectural Conservation, 8:2, 48-62.