Tips for how to mix mortar with colors

Small batches can be mixed manually.

Experienced masons know that the procedures for how to mix mortar with colors (or pigments) is a precise science of combining mortar mix, cement, pigment and water in the right proportions.

Factors such as ensuring that the mixing equipment is clean, accurately pre-measuring the materials and sufficiently mixing the mortar itself will all affect color and consistency.

Colored mortar mixes are available, however, and the Portland Cement Association (PCA) agrees that purchasing non-pigmented mortar cement and adding various pigment colors separately may be more cost-effective for large projects.

Type S and Type N mortars are most commonly used in homebuilding. The ratio of parts needed to mix mortar with colors is outlined in the tables below.

Measuring sand

When measuring sand, PCA recommends using a cubic-foot container to add sand to the mixer. For measuring the water, measure the amount of water each time using the same container (such as a marked bucket) to ensure batch-to-batch consistency.

When adding the pigments, precisely measure the water. Strict consistency in the amount of water and color added from batch to batch is critical to maintain a consistent finished color. Pigments are available in measured amounts and vary according to manufacturer.

For best results, briefly mix together about three-fourths of the required water, one-half of the sand and all the cementitious materials (including pigment). Next, add the rest of the sand, then the remaining water to bring the mortar to its ideal working consistency.

For larger batches, PCA recommends mechanical mixing with conventional rotating-spiral or paddle-blade design mixers with tilting drums. When all batched materials have been placed into the mixer, including pigment, mix for a full five minutes. Batching procedures will vary with individual preferences.

How to mix mortar with colors

Sakrete advises mixing only enough mortar to last an hour, even less in hot or windy weather because these conditions can dry the mortar. “You have to pay attention to the consistency of the mixture,” says Sakrete’s manufacturing manager Bob Schmidt. “As the mason gains experience, he or she will be able to tell if the mortar’s not mixed properly before it’s installed.”

Retempering mortar, or adding extra water to maintain its workability, can lessen its strength. Although Sakrete recommends not retempering mortar, the American Society for Testing and Materials allows mortar to be retempered one time and recommends discarding within 1½ hours if not used.

Finally, take time to clean the mixing equipment between batches, because any materials left on the equipment will affect the color of new batches of mortar. Thoroughly cleaning the mixing equipment is recommended immediately after mortar discharge using pressure washers and stiff bristle brushes, if needed. It is important that every exposed surface of the mixer is cleaned regularly throughout the course of the project.

How to mix mortar, type S

How to mix mortar, type N