Hot Lime Mortar Course

This workshop is designed to provide an introductory guide to the preparation and application of "hot mixed" lime mortars. These mortars are made by slaking quicklime and combining it with sand, natural hydraulic lime binders, and potentially other additives like tallow.

"Hot mixed" mortars have a long-standing history of use in the UK, with visible evidence in traditional buildings and structures throughout the country. However, since the lime revival of the mid-1990s, the field of conservation mortars has largely been dominated by lime putty-bound mortars or "cold" mortars based on natural hydraulic limes (NHLs). While all these types of mortar serve their purpose, there’s been a renewed interest in the production of what are considered more authentic mortar preparations using quicklime and sand. This workshop aims to guide building professionals through the process of specifying "hot mixed" mortars, addressing health and safety implications, materials, preparation, appropriate mixing equipment, and the specific applications for these mortars.

By the end of the course, participants will be able to identify traditionally made "hot mixed" mortars in historic structures and develop the skills necessary to specify these mortars based on authenticity, performance, conditions of exposure, seasonal considerations, the substrate, and the nature of required masonry repairs.

This course targets building contractors—including stonemasons, bricklayers, lime workers, and laborers—as well as specified professionals such as architects, building surveyors, engineers, and heritage professionals involved in historic building repair, reconstruction, and the consolidation of historic structures. It aims to instill confidence in the successful making and use of "hot mixed" mortars.

Additionally, owners of historic buildings may find this course beneficial for planning maintenance, renovation, or conversion projects for traditional structures.

After the course you should have an: Ability to recognize traditionally made "hot mixed" mortars in historic buildings and structures, Understand analysis techniques to effectively match and specify "hot mixed" mortars for repair work,
Develop repair strategies suitable for masonry repair projects using "hot mixed" mortars, be able to create clear and detailed specifications for "hot mixed" mortar, understand the setting characteristics and aftercare required for the successful use of "hot mixed" mortars.

Course Programme

The course will combine theoretical instruction with practical sessions covering: Health and safety

• Historic preparation and use of lime (and other) based mortars.
• Overview of the range and production methods of lime binders available in the UK today.
• Exploration of other mortar components, including sands, aggregates, pozzolans, and additives such as animal fats and milk products.
  Justification for specifying "hot mixed" mortars, addressing issues of authenticity, performance, and workability.
• Identification of potential failure causes, such as slow slaking, slow carbonation, and environmental factors.
• Developing specifications for lime mortar repairs, including mix proportions, mixing equipment, and Building Standards.
• Addressing perceived barriers to specification, including health and safety considerations for storing materials, mixing, and safe use.
• Best practices for producing sound specifications for "hot mixed" mortars.