Lime CPD - Architects team building walls

— 15 Nov 2021

A lesson in the theory behind mortar mixes

A practical demonstration

Getting stuck in

Hot lime mixes can reach temperatures of c.250 degrees centigrade. At least one bucket suffered as a result

As part of our Continuing Professional Development (CPD) programme, the team from each of our design studios donned their goggles and gloves and headed outdoors for some hands on practice in mixing hot and cold lime mortars and renders.

The technical team are used to specifying various mixes for different jobs on site, but there is nothing like trying it out to see how the product works and responds in the real world. Much of the Jonathan Rhind Architects CPD requirement is completed as lectures or presentations, so it was a refreshing change to get out in the fresh air and get stuck into some practical experimentation.   

The day consisted of:

• Playing around with the different hot mixing and cold mixing mortars with a variety of limes and sand mix ratios.
• Hot mixing and cold mixing limewash was tested and a couple of panels were rendered with these mixes.
• Construction of a small random rubble stone wall with the different lime/sand mixes.
• The random rubble stone walls and rendered panels will be monitored over the coming weeks to see how each mortar has set and how strong they are in comparison to each other. 

Lime mortars and renders were used extensively historically, so understanding how different mixes are created and perform is crucial in the conservation of historic buildings. Considerations for Architects and Technologists when specifying lime mortar and render mixes include: compatibility with existing mortars; hydraulicity; the type of lime and mix used will affect breathability and durability; and exposure which will affect setting.

This was a great opportunity to experiment with the product and learn from, and with, each other. Great fun was had by all and the weather was kind on both days, with blue skies and unseasonably warm weather making for a pleasant afternoon outside.