Bad Practices: Cement Render
Devon Cob Barn Failure
Britain has many earth buildings across the country, going by different names in different regions. Cob is the term used in the west country. Cob buildings need to be repaired with the correct materials and well maintained and can last hundreds of years.
Devon has more cob buildings than any other county, at the last estimated to 40,000 The oldest cob building is thought to date from around the 14th century
The earliest buildings tended to be built on a stone plinth perhaps just 18″ above ground level Some later buildings can have a stone plinth extending as high as the 1st floor joist level
There are no exact figures but certainly hundreds of cob buildings have been lost in the last dozen years due to poor maintenance or the wrong materials such as this example.
The overhang of this roof is poor, so cannot adequately take the rain water away. At least some of the repairs have been done with cement.
The render is a hard cement render that has cracked and can allow moisture to saturate the walls and seriously effect it’s structural integrity. In this case, the neglect and wrong materials resulted in major failure.
Fortunately, although the damage was severe, Mike Wye & Associates were able to rebuild the wall in mass cob once more and use green oak timber in the repair work.