• Potentially a steel frame with a masonry facing and a drainage cavity;
  • Mortar which probably contains masonry cement (Portland type cement)
  • Exposure to the elements, such as wind, rain, frost, etc.;
  • Change of use;
  • Cause of deterioration.

Walls built between 1940 and 1975 can be constructed from a steel structure with which we simply just attach a masonry facade. These walls are often constructed using a mortar made of masonry cement or mortars containing pure lime and Portland cement.

For these buildings, it is imperative to determine the cause of the deterioration. It is not common to have to restore buildings of this age. It is therefore necessary to know whether the composition of the walls, including the selection of the original mortar, is at issue. If yes, it might be better to move away from the original mortar, probably rich in cement, and rather use a mortar rich in lime.



Most of the structures built between 1940 and 1975 were constructed from a mortar field mixed on site. Although a number of these projects contain lime, many have an inadequate sand-binder ratio or inconsistent blend from the beginning until the end of the project. So in order to avoid ratio or consistency issues, it is important to select a premixed mortar containing lime. For the type of binder that was likely used during the original construction, refer to the document: Guide to identifying the different types of binders, available on this website. 


Repointing requires that the new mortar be equal or weaker, in terms of compressive strength, than the original mortar and the masonry unit. The new mortar should also be equal to or greater than the original mortar in terms of water vapour permeability. Finally, the selected mortar must accompany the original mortar in all its facets and not represent a constraint.


The basic rule in terms of compressive strength is to always be equal or weaker than the original mortar. When in doubt always select a weaker or more porous mortar. It will be easier and less expensive to redo masonry joints than having to change masonry units.


» Requiring low to medium compressive strength

  •  For non-load bearing interior and exterior walls: HLM-500 or MasonMix

» Requiring higher compressive strength

  •  Load-bearing wall, parapet, foundation, chimney, retaining wall or any masonry work exposed to a high level of saturation: MasonMix 600 or RosenMix 500

» Requiring low to medium compressive strength

  • For non-load bearing interior and exterior walls:HLM-350 or MasonCare 300 or MasonCare 1258

» Requiring medium to high compressive strength

  • Load-bearing wall, parapet, foundation, chimney, retaining wall or any masonry work exposed to a high level of saturation: HLM-500 or MasonMix 600

» Walls highly exposed to de-icing salts : Reconstec 900


*For all projects dated after 1840, when a rapid initial setting time of the mortar is necessary,the use of mortars containing natural cement is recommended. RosenMix 350 or RosenMix 500