Different Types of Mortar and How To Use Them

There are four main types of mortar mix: N, O, S, and M. Each type is mixed with a different ratio of cement, lime, and sand to produce specific performance characteristics such as flexibility, bonding properties, and compressive strength.

Type S mortar is a medium-strength mortar (minimum 1800 psi). It can be used for exterior walls below grade and other exterior projects like patios because it is stronger than Type N. It is a good option for resisting moderate soil pressures below grade because it also has higher bonding and lateral strength than type N.

Masonry Cement & Mortar Mix Types and Strengths

Why is it important to know the types of mortar?

How secure and long-lasting a project is depends on the type of mortar you use. The safety of large structures, such as homes and other buildings that house people and shield them from the elements, depends particularly on selecting the right mortar. Using the right mortar helps your project last a long time by preventing costly and dangerous problems like collapsing structures or crumbling masonry.

What is mortar?

Mortar is a substance used in construction to secure or adhere masonry pieces together to create a structure. The various components of a building and some types of sidewalks are among these structures, but you can also use mortar to create sculptures, home décor, and retaining walls. There are four ingredients in all types of mortar.

Cement, hydrated lime, and fine sand are combined to make mortar, which is then liquefied for use by adding a certain amount of water to the mixture. When the mortar dries, the proportions of each ingredient change, which has an impact on its strength in the following areas:

Types of mortar in construction

Here are some specifics about a few types of mortar and their uses to help you understand the variations between mortar types used in construction:

Type N

Since it can be used for a variety of general-purpose projects, including walls and chimneys, this type of mortar is the most widely used. With average compressive, flexural, and exposure strength, it is a medium strength mix. Type N mortar is best used for decorative and non-load-bearing projects because it may not work well in bad weather. This mortar is frequently used to give a building or structure a particular look because it accepts color better than other types of mortar.

Type S

The medium-strength Type S mortar has a high lateral strength, making it suitable for projects that may be subject to side pressure from the soil, strong winds, or earthquakes. The majority of below-grade or underground projects that must withstand pressure from the sides and from above, such as foot traffic, are projects that can use this mortar. Building foundations, sewers, and brick pavement on sidewalks and patios are all applications for type S mortar.

Type M

This mortar is a fantastic option for below-grade projects and those with high foot traffic because it has a high compressive strength and manages side pressure well. For top-heavy building foundations, retaining walls, and roads or driveways, type M mortar is used. Type M mortar is best used below grade where it won’t be exposed to the elements because of its low bonding strength, which reduces the risk of collapse.

Type O

Although Type O mortar has a generally low strength level, it is effective for interior projects that are shielded from high pressure, natural forces, and extreme temperatures. Interior non-load-bearing walls and decor are some projects for this mortar type. Due to its simplicity of use, you can also use this type of mortar to repair small patches of damaged mortar on existing structures both inside and outside.

Type K

Type K mortar is still useful for historic building restoration even though modern projects don’t use it due to its low strength level. This is so that a mortar with a higher compressive or flexural strength won’t cause the masonry units of historic buildings to break, which are frequently quite weak themselves. The strength level of historic building materials work well with Type K mortar, but it should only be used on small sections of damage.


Like the other mortars mentioned above, thin-set mortar is made of cement, but it can also contain other materials like epoxy. Use this mortar for tasks requiring little weight or pressure, such as installing indoor tile on walls and floors. Thin-set mortar projects should be safely indoors, away from natural forces, and only used for decoration.

Tips to choose the right type of mortar

Here are some guidelines to help you choose which type of mortar is best for your project because choosing the right mortar is important for both safety and quality:

Consider how the mortar will interact with materials

For them to move normally together without breaking, your choice of mortar needs to be almost as strong as your masonry materials. Determine whether pressure will be applied to your project from the top or the sides to determine the strength of mortar that is required. Choose a mortar with a high compressive strength for construction projects that will bear a lot of weight, such as load-bearing walls. A mortar with a high flexural strength is ideal for projects that are subject to pressure from the sides, such as retaining walls.

Think about the purpose the mortar will serve

When deciding which type of mortar to use for your project, consider whether it will be strictly functional or decorative. For instance, if you were building a brick wall, type N mortar would be a good option because it allows you to customize the color while still serving both functional and decorative purposes. Consider the durability of your mortar in a project before considering its appearance because, for the majority of projects, safety is more important than style.

Determine what the mortar will be exposed to

Different types of mortar respond differently to exposure to natural forces. Determine how weather conditions, such as wind, rain, and extreme heat, will affect your project before selecting a type of mortar. Some weaker types of mortar may lose their effectiveness when exposed to the elements, so compare each mortar’s specifications to the needs of your project to make the best decision.


What are the 4 types of mortar?

The four most popular types of mortar are Type N, M, S, and O. Although ASTM C 270 describes these types of mortar in great detail, we will briefly discuss the traits and ideal applications of each type here. The most popular type of mortar, Type N, is typically advised for exterior, above-grade walls.

What are the 5 types of mortar?

Types of Mortar
  • Cement Mortar.
  • Lime Mortar.
  • Surki Mortar.
  • Gauged Mortar.
  • Mud Mortar.

What is Type S mortar used for?

  • Bricklaying or Stone Laying Mortar. Ad. …
  • Finishing Mortar. Finishing mortar is used for pointing and plastering works.
  • Cement Mortar. Sand serves as the aggregate and cement serves as the mortar’s binding component.
  • Lime Mortar. Ad. …
  • Gypsum Mortar. Ad. …
  • Gauged Mortar. …
  • Surkhi Mortar. …
  • Aerated Cement Mortar.

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