When choosing mortar, the impulse may be to purchase the strongest type available. This is often a bad idea: mortar is used to hold brick together but should also be able to absorb impacts allow for a little give, allowing the entire brick structure to stand. Below is a primer on choosing mortar as well as the five most common mix types you will encounter at your local home improvement store.
Mortar is bought as a combination of Portland cement and sand. Water is added, creating a chemical reaction that creates a curing process similar to concrete. Each type of mix has specific strengths and weaknesses. A particularly strong mortar may not work well with some brick projects and be difficult to work with. A mix that is easier to work with may sacrifice some strength, but allow the user to create a better project overall.
Type N is of medium strength, which means it is the best choice for projects with bricks that are not load bearing. Garden walls, chimneys, and barbeques are common applications for this mix. Type N is also preferred for soft stone masonry. This is the mortar most often used by home owners. It is easy to work with and is appropriate for most brick projects that the typical home owner would attempt.
Type S is known for its strength and is used outdoors. Patios, foundations, and retaining walls all use Type S, which is known for its ability to absorb most impacts. Type S is still an easy product to work with, but homeowners should have some experience working with brick before beginning any type of project that requires this product.
The strongest mix that you will find in a home improvement store, Type M is typically used only with stone. Type M is preferred with stone because the strength of the mortar typically mimics that of the stone being used. It is also used in situations where being able to bear heavy loads are important, such as retaining walls.
Glass Block Mortar
This specialty mortar is actually a Type S mortar that is colored for use with glass block, not brick. Rather than the traditional gray color, glass block mortar is white and can be tinted to match the material. Of course, because the color is the only significant change in this type of mortar, Type S mortar can also be used for glass block projects.
Refractory mortar is used when heat is of a concern. This product, though more expensive than other formulas, is the best choice if you are building or repairing a barbeque or chimney that will be used regularly or exposed to high temperatures. Created with a calcium aluminate base, it will cure in wet conditions and resist melting in incredibly hot temperatures.
Most home improvement project’s success depends on the quality of materials chosen and the research that goes into the project before it has begun. If you are contemplating working with brick or building something with brick, take the time to choose the right product for the task. Keep in mind that each manufacturer will have different usage instructions and a slightly different mix for their products. Take the time to read the instructions that come with the mix you buy and be sure to contact the manufacturer with any questions before beginning to work with brick.