In Haddenham and parts of Buckinghamshire west of Aylesbury are a number of villages whose cottages have rendered walls. These are mostly built in 'wychert (or more commonly, 'witchert'), which is Buckinghamshire's version of the cob or earth-wall constructionmore usually associated with Devon and Dorset. Still used in this part of Bucks until the 1920s, witchert is a corruption of 'white earth' which roughly describes the lime rich sub soil that lies above the Portland Limestone belt that passes through the Vale of Aylesbury.
Walls were built by piling the sub soil in heaps alongside a plinth wall of local field limestone known as a 'grumpling', itself a corruption of groundling. The heaps were then thoroughly soaked, mixed with chopped straw (to make the glutinous mix workable) and laid in 'raises' or 'berries' each about 18 inches or half a metre high. As each layer dried a further layer was smacked on top, using a trident-like long handled fork. Berry was added to berry until thedesired height was reached, doors, windows and floors being built in as needed. The surface was then dressed with a sharpened spade and often washed over with a diluted wash of the subsoil to provide a smooth surface.
Provided the tops are protected from the weather and the grumplings remain above soil level a witchert wall should last for centuries and and there are many 17th-century buildings surviving in these villages. Witchert was used for dwellings, farm buildings, boundary walls and even chapels. Houses were usually rendered but many outbuildings and walls were not, so these can be examined closely to see the grumplings and the berries. The walls, often built over two metres high to prevent cattle grazing their original thatched tops, curve and swoop to give a sense of enclosure and intimacy and it is a tribute to the quality of witchert that you can build walls over two metres high that are only 225mm thick, unlike in Devon or Dorset where that are more likely to be 500mm minimum. A wonderfully versatile and attractive material that givesthese villages a very distinctive character and one not found elsewhere in Buckinghamshire.