Understanding Types of Mortar Strengths and Uses

Understanding Mortar Strengths

Mortar strengths are determined by laboratory results, which average out to give us a reliable measure. Each type of mortar is matched with its specific use. It’s important to remember that sometimes mortar acts as a sacrificial layer in case of wall shifts, meaning it should be weaker than the materials being laid. For reference, a CMU block has an average strength of 2000 PSI.

Types of Mortar: MaSoNwOrKs

To remember the types of mortar, we use the mnemonic MaSoNwOrKs, striking out every other letter. This leaves us with M, S, N, O, and K. These designators don’t stand for anything specific but help us categorize the different types.

Type M Mortar

• Strength: 2500 PSI
• Use: Maximum strength, typically used below grade. Often specified for seismic zones or hurricane-prone areas like Miami-Dade County.

Type S Mortar

• Strength: 1800 PSI
• Use: Structural, general-purpose mortar. It’s versatile and can be used both below and above grade, including for brick veneer. However, for some applications, Type N might be a better choice.

Type N Mortar

• Strength: 750 PSI
• Use: Normal for veneer or fascia, commonly used with bricks. Preferred by bricklayers due to its lower shrinkage, resulting in a better-finished brick wall.

Type O Mortar

• Strength: 350 PSI
• Use: Tuckpointing mortar, a specialty mortar used for repairs. Its lower strength ensures it doesn’t damage the existing structure.

Type K Mortar

• Strength: 75 PSI
• Use: The weakest of the mortar types, used strictly for historical preservation. Its use is typically specified by architects for restoration projects.

Conclusion

These are the types of mortar and their uses. At Amerimix, we have all these types available, ensuring you have the right mortar for any job. Whether you need maximum strength or a specialized repair mortar, we’ve got it in the bag.