1) Head of Sustainability & Construction Materials, Lucideon, UK,

2) Senior Marketing Manager Materials, Lhoist, Belgium,

3 Marketing Manager Construction, Carmeuse Europe, Belgium,

4 Technical Sales Manager, LafargeTarmac, UK,


The European Lime Association (EuLA) have instigated a project to identify and quantify the benefits associated with the addition of hydrated lime to cement based mortars, and more importantly, filling the gaps that exist in the evidence in respect of the benefits of hydrated lime additions to workability, bond strength development, durability and in addition the modes of failure of mortars whne subject to lime additions.

This paper focuses on and assesses the benefits of hydrated lime additions to cement based mortars in respect of mortar and masonry durability. For the purposes of this project, “durability” has a wider context than typically used, and is defined as the following properties:

  • Accommodation of movement (in the masonry)
  • Protection from rain penetration
  • Moisture vapour permeability
  • Resistance to salt crystallisation
  • Freeze-thaw resistance

The paper reviews the existing scientific literature and reports on the results of a testing programme on masonry panels, built with different mortars, both in the laboratory and in exposed field sites, highlighting the areas where there are tangible and measurable benefits to the performance of the mortar by the addition of hydrated lime.


Keywords: hydrated lime, mortar, durability, rain penetration, movement, salt crystallization