Wendy's technical term of the month - Slobbered Limestone

“When planning to alter a finish we should always take into consideration why the work was done in the first place and specific finishes should be replaced like for like.”

Belham Hayes Slobbered Limestone aggregate.jpg

The term ‘slobbered limestone’ seems to be more popularly used in the north of England nevertheless there are many examples on vernacular buildings in exposed areas elsewhere that are prone to wind-driven rain. In such places, buildings of rubblestone have often been rendered, if not fully rendered, then walls were ‘slobbered’, that is pointed with a thickly applied mortar. A high proportion of mortar to limestone rubble was important applied full to the face of the stonework in several coats and limewash then applied. The lime mix used often contained a large aggregate which can look much like modern pebbledash. Along with the limewash applied onto it, slobbered coats stop rain from penetrating stonework, the aggregate forming a large surface area which stops rainwater running down walls and lets it dry out with the help of the wind and the sun.  

Over time, mortar coats have often degraded and fallen away, leaving a flush pointed finish exposed that can allow wind driven rain to penetrate the pointed wall beneath and cause problems with damp. Misunderstanding of this method and the fashion for exposing stone means that the pointing is often brushed back too far between the stones to make them visible. Some stonework was never meant to be seen, walls having been built to be rendered or ‘slobbered’ for their weather protective qualities rather than their aesthetic ones.

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