Timber Revetments
Revetments are short-parallel structures that slope from the bed of a body of water up onto a piece of land. They act as human-made barriers between the earth and bodies of water. In medieval London and still today, they are used to stop environmental hazards such as erosion on softer landforms.[1] Revetments also kept the water within moats during low tide.[2] Most medieval revetments found at excavations sites date from the twelfth to fifteenth century. Archaeologists discovered medieval timber revetments inLondon during riverfront excavations along the Thames during the twentieth and twenty-first century.[3] Although many medieval wood objects did not survive because of damage from fires and rotting,[4] some timber revetments have survived because they were in oxygen-free waterlogged conditions, which was the case for the revetment built at Billingsgate and excavated in the 1980s.[5]
Archaeologists have argued that there were no carpenters who specialized in revetment building since the general techniques employed to build revetments were also utilized for constructing buildings and even ships. Therefore, the same carpenters responsible for construction elsewhere in London most likely also built the Thames river revetments.[6]
The only named carpenter associated with building revetments in the city of London was Richard Cotterel, who was employed to help rebuild the timber face of the Broken Wharf in 1347. Although the Broken Wharf and timber revetments are two different projects, the techniques utilized in both projects were very similar. For instance, revetments along the Thames share similar bracing and plank cladding as employed for other types of wooden structures in harbor installations.[7] The size of the revetment depended upon the current and height of the tide at the location where the revetment was placed along the river. In short, the amount of erosion protection that the land required dictated the construction characteristics of the revetments.
Dating revetments is difficult for many archeologists because of timber’s susceptibility to the elements, which makes it hard to tell how old the revetments are. Dendrochronology (tree-ring dating) can help date when the trees were initially cut down, but it does not reveal the date when carpenters used the timber as revetments. Many revetments also were made of re-used timbers; in their past lives they were used to construct buildings, ships, and barrels before they become timber revetments.[8]
Revetments differed in height. The revetments found at Billingsgate are approximately 2 meters in height.[9] Wherever found, timber revetments were a similar brown color. It is important to note that the words timber and wood are not synonymous. They are two types of different woodland resources. There is no defined point when wood becomes timber, but the general rule is that any wood at or over .15m in diameter is considered timber.[10] Much of the timber found in excavated embankments were unworked branches and therefore not technically timber.
The study of timber revetments has aided archeologists and historians in better understanding medieval carpentry and building techniques. For instance, by studying timber revetments, we now understand that medieval carpenters who built timber revetments were familiar with the techniques of wood framing and posts used for dry-land buildings. The study of timber revetments and houses on the London waterfront has also revealed the abundance of timber buildings in London during the eleventh, twelfth, and thirteenth centuries.[12] At the same time, revetments can indicate the location of encroachment into the Thames over time. Therefore, these objects not only allow us to understand medieval building materials and techniques, but they also illustrate human attempts to hold back erosion from the middle ages to the twenty-first century.[13]
Most carpenters used oak to construct timber revetments, the same type of wood commonly used in medieval housing. However, based on discoveries at Billingsgate Lorry Park, a few carpenters used nonindigenous pine.[14] Archaeologists believe that medieval woodmen used axes to fell trees and then harvested the wood for structural purposes. Historians, however, know very few details about this wood harvesting.[15]
The findings of archeologist have given us insight into the use of revetments during the medieval era, but timber revetments are a technology that we still use today to help combat erosion.[16] However, most carpenters in England now use tropical hardwoods to build revetments.[17] Medieval London was not the only place where people used and built revetments. People who lived near water in other parts of Europe, such as Scandinavia, utilized revetments between bodies of water and land.
Medieval Londoners greatly benefitted from the ability of revetments to prop up the riverbank to prevent erosion along the Thames River. Revetments protected the lands of both wealthy fishmongers and impoverished tenants who lived along the Thames River in London.
--Abigail Monaco
Endnotes
[1] “ Revetments.”
[2] Milne, The Port of Medieval London, 121.
[3] Milne, Timber Building Techniques in London, 10
[4] Milne, Timber Building Techniques in London, 11.
[5] “Revetment Timber,” Museum of London.
[6] Milne, Timber Building Techniques in London, 106-110
[7] Milne, Timber Building Techniques in London, 10-11
[8] Milne, Timber Building Techniques, 108
[9] Milne, The Port of Medieval London, 18
[10] Milne, Timber Building Techniques in London, 108
[11] Milne, Timber Building Techniques in London, 86
[12] Milne, Timber Building Techniques in London, 131
[13] Milne, “The Port of Medieval London,” 18
[14] Steedman, Dyson, and Schofield The Bridgehead and Billingsgate, 66
[15] Milne, Timber Building Techniques in London, 106-110
[16] “Revetments.”
[17] Milne, Timber Building Techniques in London, 108
Works Cited
Blinkhorn, P., & Pugh , G. Excavation of the Medieval Waterfront at King Stable Street, Eton, Berkshire. Oxford Archeological Unit . Oxford, 1997.
Milne, G. Timber Building Techniques in London c.900-1400. London & Middlesex Archaeological Society Special Paper 14. London: Museum of London, 1992.
Milne, G. The Port of Medieval London. London: Tempus Publishing, 2003.
"Revetment Timber." Museum of London Collections Online. Retrieved September 29 , 2020, from https://collections.museumoflondon.org.uk/online/object/318157.html
"Revetments." Climate Technology Centre and Network. Retrieved September 29 , 2020, from https://www.ctc-n.org/technologies/revetments
Steedman, K., Dyson, T., & Schofield, J. Aspects of Saxo-Norman London: III. The Bridgehead and Billinsgate to 1200. London : The Museum of London and the London and Middlesex Archeological Society. London, 1992.