How to Mix Mortar ?

 Mortar mix is a critically important bonding material used in construction. It is used between brick, stones, concrete blocks and other masonry materials. Mortar can be made out of Portland cement, lime, sand and water.

How to mix mortar; Image Courtesy: Home Fixated

As per ASTM, the mortar mix used can be Type N, M, S, and O. Each mix possess different performance characteristics for building applications.

What is the Procedure to Mix Mortar?

Mortar is mixed in large amounts using a mixer. Smaller amounts of mortar can be mixed by hand, a hoe, a mixing container and wheelbarrow. The procedure to mix mortar include:

1. Measure the mortar materials using a dry bucket. Presence of moisture in the materials result in bulking and increase in volume.

2. Before, filling the containers with fresh water, pre-wet the containers. The container prepared must be flat with solid surface base and tall sides. This helps to mix the mortar properly with hand.

3. Add cement, lime and sand as per the ratio and mix it thoroughly in the container. After this, add water on the top of dry ingredients.

4. The mortar mix is taken from the bottom and added to the water depression created. Keep on mixing, until the water is mixed in. Add more water and keep mixing. This is continued till a smooth consistency is obtained.

5. Stop the mixing process when the mortar in the wet state slip easily off the shovel but holds its shape when a hollow is made in the mix.

6. Make few ledges in the mortar mix. If the ledges stay up, then the mortar mix has attained required viscosity.

What is the Procedure to Mix Mortar?

Tips to Mix Mortar Efficiently

To achieve best results during mixing mortar, the following steps can be followed:

1. Wear eye protection and waterproof gloves when mixing mortar.
2.  Choose the correct type of mortar mix.
3. Use fresh cement to mix the mortar.
4. Use of cement present in open bags would have absorbed environmental humidity. This changes the water percentage of the mortar mix.
5. The mortar mix stays good for 90 minutes. After which it looses its properties.
6. The weather condition affects the reaction and properties of mortar. So plan properly for weather conditions.
7. Try to maintain consistency while measuring materials for mortar. Use the same measuring can or bucket for proper consistency.
8. Mix the mortar not less than 3 minutes and not greater than 5 minutes. This is the type just counter after the addition of last material to the mix.
9. In hand mixing, water must be added after mixing all the dry ingredients.
10. If the mortar mix starts to dry, add water. Do not add water if the mortar starts to set.
11. The workability of the mortar mix can be increased by adding chemical plasticisers or masonry cement.
12. Waterproofing agents can be added to the mortar to prevent the effect of damping.
13. The fine sand used in the mortar mix must be good grade. The sand must be free of clay.
14. Sand must be stored in a dry place and not to absorb water.
15. Portland cement is recommended for mixing mortar.

Also read: How to Calculate Cement Required for Floor Tiling?

Problems during Mixing Mortar

• Once the mortar mix starts to set, it cannot be re-mixed as it will reduce the mortar's strength. 
• Addition of too much water to the mix affects the chemical composition, strength and potential problems in future.
• Addition of wrong admixture affects the bonding and the strength capabilities of the mortar.

Read More: Plastering - Requirements, Types and Specifications