The Difference Between Type S and Type N Mortar

When it comes to masonry and restoration projects, choosing the right mortar type is essential to ensuring structural integrity, durability, and long-term performance. Among the most commonly used mortars in construction and restoration are Type S and Type N mortars. Each of these has distinct characteristics and best-use cases. Knowing the difference helps homeowners and contractors make informed decisions for various masonry projects.

What is Mortar and Why is it Important?

Mortar is a blend of sand, water, and cement that binds bricks, blocks, or stones, forming a sturdy, durable structure. Depending on the project, the right mortar type enhances structural stability, supports loads, and protects against environmental factors like moisture and temperature changes. Choosing between Type S and Type N mortar can affect both the look and longevity of masonry projects.

Overview of Type S and Type N Mortars

Type S and Type N mortars are both widely used in masonry, yet they have different compositions and strengths, making them ideal for specific purposes.

Type S Mortar

Type S mortar is a medium-strength mortar with a high compressive strength of at least 1,800 psi (pounds per square inch) and excellent bonding properties. This type of mortar is typically used in applications requiring high strength and resistance to harsh weather, such as below-grade or outdoor structures.

Key Characteristics of Type S Mortar

High Strength: Minimum compressive strength of 1,800 psi, suitable for load-bearing walls and structural applications.
Durability: Excellent resistance to wind, seismic forces, and underground pressures.
Versatile Usage: Frequently used in retaining walls, foundations, and other structures exposed to significant stress and weathering.

Type N Mortar

Type N mortar is a medium-strength mortar as well, but with a lower compressive strength of approximately 750 psi. It’s commonly used for above-grade, exterior, and interior applications, where high compressive strength is not a critical requirement.

Key Characteristics of Type N Mortar

Moderate Strength: With a compressive strength of 750 psi, it's ideal for applications where flexibility and bonding are prioritized over maximum load-bearing strength.
Adaptable Application: Often used for above-grade walls, chimneys, and exterior facades.
Aesthetic Finish: Type N mortar is easier to work with and provides a smoother finish, making it suitable for decorative and non-load-bearing structures

Differences Between Type S and Type N Mortar

Understanding the differences between Type S and Type N mortar is crucial for selecting the right one for your masonry project. Let’s examine their distinctions in strength, composition, uses, and resistance capabilities.

Strength and Durability

Type S Mortar: Known for its high strength (1,800 psi), Type S mortar can support heavy loads and withstand pressure, making it ideal for load-bearing structures.
Type N Mortar: With a compressive strength of 750 psi, Type N mortar is better suited for walls and structures where flexibility is needed rather than maximum load capacity.

Best Applications

Type S Mortar: Commonly used for foundations, retaining walls, patios, walkways, and other outdoor applications that require durability against moisture and pressure.
Type N Mortar: Preferred for exterior and interior walls, veneers, and non-load-bearing walls, as it offers good workability and a pleasing finish for visible applications.

Weather Resistance

Type S Mortar: With its robust structure, Type S mortar is highly resistant to wind and seismic pressure, which makes it ideal for exposed areas.
Type N Mortar: While it offers good weather resistance, it’s best used in milder climates and areas not exposed to excessive moisture or extreme conditions.

Workability and Aesthetic Appeal

Type S Mortar: Due to its higher cement content, Type S mortar can be harder to work with and may not provide as smooth a finish as Type N mortar.
Type N Mortar: Easier to spread and smooth, making it a better choice for decorative applications where appearance is a priority.

Composition and Mixing

Type S Mortar: Generally made with two parts cement, one part lime, and nine parts sand. The higher cement content contributes to its strength and durability.
Type N Mortar: Contains one part cement, one part lime, and six parts sand, offering moderate strength and a smoother, more workable mix.

When to Choose Type S Mortar

Type S mortar is best suited for masonry applications requiring high strength and resistance to environmental stressors. Here are some situations where Type S mortar is the optimal choice:

Load-Bearing Walls: Ideal for structures that must support substantial weight, like basement walls or retaining walls.
Foundations and Footings: Strong enough to withstand underground pressure, making it ideal for below-grade construction.
Exposed Structures: Use for projects in areas with severe weather conditions, high winds, or seismic activity, as Type S mortar is durable and resilient.

When to Choose Type N Mortar

Type N mortar is generally used in non-load-bearing applications where appearance and workability are important. Here’s where Type N mortar shines:

Interior and Exterior Walls: Suitable for above-grade walls, especially for homes and buildings where moderate strength is sufficient.
Veneers and Decorative Work: Its smoother finish makes it ideal for visible brick facades, decorative stone work, and other aesthetic applications.
Chimneys and Fireplaces: Works well in fireplaces and chimneys that do not require heavy load-bearing capacity.

How to Choose the Right Mortar for Your Project

Choosing between Type S and Type N mortar depends on several factors:

Project Requirements: Evaluate the structural needs and load-bearing demands of the project.
Weather and Environmental Conditions: Consider the climate and whether the structure will be exposed to severe weather or seismic activity.
Aesthetic and Functional Needs: For decorative work or projects where finish quality matters, Type N mortar may be preferable due to its smoother finish.

Consulting with professional masons or restoration experts, like JMS Masonry & Restoration, can help ensure the right mortar type is selected to achieve the best results.

When choosing a team of experts, make sure you ask about their warranties.

Conclusion

Selecting the correct mortar type—either Type S or Type N—depends on the specific needs of your masonry project. Type S mortar provides strength and durability for load-bearing and below-grade applications, while Type N mortar offers moderate strength and aesthetic appeal for above-grade and decorative projects. By understanding the distinct qualities of each, you can ensure your masonry work remains structurally sound and visually appealing for years to come.

Ready for your free consultation? Contact JMS Masonry today!

FAQs

Can Type N mortar be used for a load-bearing wall?

Type N mortar is not recommended for load-bearing walls due to its lower compressive strength.

Is Type S mortar suitable for indoor applications?

While it can be used indoors, Type S mortar is typically reserved for high-strength, outdoor, or below-grade applications.

Which mortar type is better for a brick veneer?

Type N mortar is generally better for veneers, as it provides a smooth finish and sufficient strength for non-load-bearing walls.

Can Type S mortar withstand freezing temperatures?

Yes, Type S mortar is highly resistant to freezing and thawing cycles, making it suitable for colder climates.

How can I determine the right mortar type for my project?

Consult with a masonry professional to assess project requirements, environmental exposure, and structural needs.