The word Wychert means “white earth” it is a sticky white sub soil found largely in the vale of Aylesbury. Many old houses in the area have walls that were constructed simply by piling up this material in layers and letting it dry. There are thousands in this country, but sometimes people living in them do not even know.

It is believed that this type of earth can be found as far up as Norfolk, spreading down through the country in a band all the way to Devon and Cornwall where it is called “Cob”. The earth in Devon is currently mixed with sand and straw before it is used, where as the Wychert is just mixed with straw. This introduction of sand or shillet (a gravel of crushed shale) happened in 1994 when Kevin McCabe built a two-storey, four bedroom cob house. Kevin put sand into the mix to try and reduce shrinkage.

We believe that Cob is not as strong as the Wychert from our area. Evidence of this would be the thickness of the Cob walls, which are generally about 15 - 30% thicker than the Wychert walls found locally. We have seen signs that when Cob blocks are used for repair they have been unsuccessful. In the past we have made our own Wychert blocks which greatly reduce the drying time needed for traditionally built walls, and repairs.

Being a natural building material Wychert requires natural products to compliment it. The use of cement and Gypsum based product are avoided as much as possible, along with modern paints as they stop walls breathing trapping in moisture. Instead lime and lime based products are used, which work with the Wychert allowing it to breath.

We have learnt form a long line of local tradesmen who also owned and maintained Wychert properties. We ourselves live in a converted Wychert barn that we converted in 2003; so you could say Wychert is at the core of Buildright (UK) Ltd. It is this “closeness” with Wychert that has given us great insight into how it behaves, and has allowed us to identify the key factors that aid the long term success of restoration work.


If you have a period property that requires lime rendering or Wychert repair Contact Us today to see how we can help you.