Making Brick Mortar

A worker laying bricks into mortar to create a brick wall.
What You'll Need
Hydrated lime
Portland cement

Brick mortar, or bricklaying mortar, is an excellent product that is specially made to hold bricks together. Although this substance looks like a simple mixture, a lot of science is involved in the making it. In fact, there are many different kinds of brick mortar, each with different kinds of properties.

Select the Proper Ingredients

As mentioned before, there are a lot of different mixtures for brick mortar, but these basic components transfer to most types: Portland cement, lime, and sand.

Portland cement is the main ingredient in brick mortar and the one that gives it durability. Natural lime can be used to make bricklaying mortar, but hydrated lime is actually the better option as it is often the more reliable of the two. Sometimes, bad-quality natural lime can lead to structural problems with the mortar, and it is simply more likely to happen than with hydrated lime.

Also, the sand that you choose should be clean and washed. Although there are many kinds of sands available commercially for construction purposes, it is important to choose one that has the right texture and color. It is extremely important to find the right kind of sand, because it gives the mortar its color as well its strength.

Why it Is Important to Mix the Right Quantities

Mixing the ingredients in the right quantities will ultimately affect the mortar’s quality, so it’s important to know what you need. For instance, if the lime to Portland cement ratio is not in the right proportion, the mortar will be extremely weak. The more lime you add to the mortar, the weaker it becomes. However, lime is also important for the mortar mix, since it offers a healing property to the mortar. Hydrated lime can add crystals to the cracks in the cement that eventually get into the mortar upon aging.

What Is it Being Used For?

The proportion in which to mix the ingredients depends on the use that the mortar is intended for. For example, lime actually has a self-healing characteristic. Hydrated lime can grow into small cracks in mortar and essentially repair them. It also causes mortar to be a little more flexible, if less durable, so for a structure that may suffer more abuse or shifting over time, you would use a higher concentration of lime in the mixture. If you have freezing weather in the location where you are using the mortar, the mortar should be able to withstand the cycles of freezing and thawing. The ingredients, therefore, would be mixed in different ratios.

Mixing a General-purpose Mortar

For simple brick mortar, the amount of lime added is actually very little, only about 10 percent of your total volume; Portland cement and sand make up almost all the mixture. The combination should be very rich and should not have a very stiff consistency so that it can be applied to bricks with relative ease. The perfect mix for the brick laying mortar contains two parts washed sand and one part Portland cement. Combine them in a pan, and using a medium trowel, create a homogenous mixture. Now, little by little, add water and keep blending all three. Also use the trowel to scrape the bottom of the pan every now and then to be sure everything is properly combined. The compound should be soft enough to be able to scrape right out from the bottom of the pan so it can be spread on the bricks appropriately.