Techniques > Briefs > Repointing Mortar Joints > Execution of the Work >

 

• volumetric measurement
• mixing batches


Mortar Preparation

Mortar components should be measured and mixed carefully to assure the uniformity of visual and physical characteristics. Dry ingredients are measured by volume and thoroughly mixed before the addition of any water.

Sand must be added in a damp, loose condition to avoid over sanding. Repointing mortar is typically pre-hydrated by adding water so it will just hold together, thus allowing it to stand for a period of time before the final water is added.

Half the water should be added, followed by mixing for approximately five (5) minutes.

The remaining water should then be added in small portions until a mortar of the desired consistency is reached.

The total volume of water necessary may vary from batch to batch, depending on weather conditions. It is important to keep the water to a minimum for two reasons:

    1. first, a drier mortar is cleaner to work with, and it can be compacted tightly into the joints;
    2. second, with no excess water to evaporate, the mortar cures without shrinkage cracks.

Mortar should be used within approximately 30 minutes of final mixing, and "retempering," or adding more water, should not be permitted. .