7 Types of Mortar & Their Different Uses
If you are interested in building a brick wall or putting up tile, you will need to use mortar. However, there are several different types, and choosing the wrong one could ruin the project. If you aren’t sure about which type to use, keep reading as we list the most common types and explain when to use them.
The 7 Types of Mortar
1. Type M Mortar
Type M mortar is the strongest type, with a strength of 2,500 pounds per square inch (PSI). This type is used in below-grade applications to create foundations and retaining walls. The downside to this mortar is that it doesn’t create a strong bond nor keep out water, so it’s not a good choice for above-ground applications.
- Ingredients: parts Portland, 1 part lime, and 12 parts sand
- Strength: 2,500 PSI
2. Type S Mortar
Type S is a strong mortar with a strength of 1,800 PSI, but since there is less Portland cement in relation to the other ingredients, it’s easier to work with and creates a stronger bond with brick and stone. It also helps resist water, making it good for layering brick in above-ground applications.
- Ingredients: 2 parts Portland, 1 part lime, and 9 parts sand
- Strength: 1,800 PSI
3. Type N Mortar
Type N mortar is a good choice for layering softer materials and interior and exterior walls with normal loading. It’s also a popular choice for tuckpointing, which is when you use different mortars on the chimney to give the impression of fine joints. It’s also quite flexible, making it less likely to crack.
- Ingredients: 1 part Portland, 1 part lime, and 6 parts sand
- Strength: 750 PSI
4. Type O Mortar
Type O Mortar is a low-strength mortar typically used for non-load-bearing interior applications where the wall is structurally sound. It’s also flexible, making it a good choice for masonry units with low compressive strength, like sandstone.
- Ingredients: 1 part Portland, 2 parts lime, and 9 parts sand
- Strength: 350 PSI
5. Type K Mortar
Type K Mortar is no longer used in new construction projects, but you might encounter it if you restore historic buildings, when you need to prevent damage to the fragile stone. It’s strictly for appearance and provides no load-bearing capacity
- Ingredients: 1 part Portland, 3 parts lime, and 10 parts sand
- Strength: 75 PSI
6. Type L Mortar
Type L Mortar (the “L” stands for lime) is only used for restoring historic buildings. Since it doesn’t contain any cement, it’s not an actual mortar, and its sole purpose is to tuckpoint old buildings’ chimneys.
- Ingredients: Varying amounts of lime and varying amounts of sand
- Strength: 750 and 1,800 PSI
7. Thin Set Mortar
Thin-set mortar in an epoxy mortar with high compression strength. It forms a strong bond with stone and other materials and is a good choice for humid environments. This kind of mortar is used to hang tiles in interior environments.
- Ingredients: Varying amounts of Portland cement, water retention agents, sand, and water
- Strength: Varies
Frequently Asked Questions
What Is the Mortar Used For?
Mortar is used to bind brick and stone when building walls and other structures.
What Is the Difference Between Concrete and Mortar?
Both concrete and mortar contain cement, so they are similar and easy to confuse. However, concrete will contain large rocks and chemical additives, making it stronger, so it can be used to build a wall, while the mortar is an adhesive for holding rock and brick in place.
How Long Does Mortar Last?
It can last indefinitely if the mortar stays dry. However, if it is exposed to water and other harsh weather conditions frequently, it can start to deteriorate in as little as 5–10 years.
There are several types of mortar, and the type that you will use will depend on your needs. For example, if you are hanging tile in the bathroom, you likely want to use a thin set, while a foundation will likely call for Type M mortar, which has the highest strength. Type S and Type N are the most common and are used to build most brick walls. Interior walls can use Type O if they’re primarily for appearance.
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