I am thinking of buying a cob property. What sort of issues should I be aware of?
Cob properties were generally built on a stone plinth, so don’t be dismayed that there is no damp proof course. Ideally, the property will have been maintained in the correct way, and has a sound roof that has not allowed water to leak into the cob structure.
Cob needs to maintain its own micro climate, so that it’s neither to wet or too dry. Lime mortar has a key role to play here as it allows the cob to breathe and ‘wick’ away any excessive damp.
If the cob has been incorrectly rendered with cement, then check the soundness of the structure by tapping the walls- if they sound hollow or the render has come away from the cob underneath, then you need to be aware that remedial works will have to be undertaken as soon as possible.
We always try and look at the top of the cob walls by getting up into the attic roof space, where more often than not, will give you an indication as to whether the walls are sound. If you have any doubts about the property, then it’s always best to get expert advice from someone like ourselves who specialises in working on cob buildings.