Cement or lime mortar?
When considering repointing, a common question is: "Which type of mortar should I use?" Durham Dry Stone offers expert guidance tailored to your specific wall or property needs. Generally, older structures originally built with lime mortar should be repointed with the same. Cement-based mortars, though durable, can inflict significant harm on aged brickwork or stonework. The adjacent photo illustrates damage caused by repointing a sandstone wall with cement mortar, highlighting the benefits of using lime-based mortar to preserve the integrity of the stonework. Cement mortar is also a leading cause of damp in older buildings as it does not allow the walls to 'breathe'. The inherent breathability of lime mortar allows moisture to be absorbed and released naturally helping to prevent the growth of mold and mildew, as well as ensuring the longevity of your masonry.
As a general guideline, if the structure was initially constructed with lime, it's best to repoint using lime; likewise, if it was built with cement, repoint with cement.
Lime mortar
Cement mortar
Cement mortar
A mid 19th century farmhouse of solid wall construction. Here, the soft sandstone has been meticulously repointed with a traditional lime mortar, helping to preserve the structure for years to come.
Cement mortar
Cement mortar
Cement mortar
A 1970s detached house, constructed with cement mortar, features cavity walls, a damp-proof membrane, and robust modern brick. The gable was repointed using cement to achieve a bucket handle finish