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What Type Of Mortar Is Used For Exterior Wall And Floor Tiles?

Thinking about constructing your new home? Glistening exterior walls and aesthetic floor tiles make all the difference. But, while you are dreaming about these aspects, have you ever wondered what lies underneath the tiles and bricks? 

The unsung hero behind construction projects is mortar. Just like the foundation of a building determines its strength, the mortar signifies the longevity of bricks and tiles.

It is a vital component which bonds masonry units or bricks, providing structural integrity to the floors and walls.


Now the question arises, what type of mortar is used for exterior wall and floor tiles? Not all mortars are the same. This material comes in various types and must be chosen carefully according to the intended use. 

With exterior walls tiles facing the difficulties of changing weather and floor tiles experiencing daily wear and tear, the mortar type must be correct for ultimate longevity and durability. 

In this article, we will explore mortar, discussing its various types and their applications. So, let’s get started! 

Understanding Different Mortar Types 

Understanding the distinct properties and ideal applications of each mortar type can make all the difference in your construction project.

If you’re laying tiles on exterior walls, make sure the mortar beneath is as thoughtfully chosen as the tiles or bricks it binds. After all, strength, resilience, and beauty lie in the details. Here are the main types of mortar explained: 

1. Type N Mortar

Type N mortar is the most versatile mortar suitable for most general-purpose projects. Predominantly used by homeowners, this mix is perfect for exterior walls exposed to severe weather and high heat.

Its unique composition of 1 part Portland cement, 1 part lime, and 6 parts sand gives it a medium strength, typically around 750 psi.

Features of Type N Mortar

  • It’s tailor-made for above-grade, exterior, and interior load-bearing installations.
  • Preferred for soft stone-masonry, such as limestone.
  • Exceptional for decorative ventures due to its enhanced color acceptance.

2. Type S Mortar

Now, let’s imagine a scenario where you’re looking to construct something at or below ground level, like retaining walls or sewers. Here, Type S mortar is your best bet.

Known for its high compressive strength, surpassing 1,800 psi, it’s ideal for projects demanding resilience against pressures like wind, seismic activity, and soil.

Features of Type S Mortar

  • Best for below-grade applications, such as foundations and retaining walls.
  • Its high lateral strength is perfect for locations with potential seismic activity.
  • Its flexibility is credited to its high lime concentration.

3. Type M Mortar

For those heavy-duty projects where strength is paramount, Type M mortar takes the lead. Boasting the highest amount of Portland cement, it’s the first choice for heavy loads and structures like driveways and retaining walls. Its strength, however, comes at a cost. It has relatively poor adhesion, making it less suited for exposed applications.

Features of Type M

  • Its unmatched strength, often reaching 2,500 psi, is ideal for load-bearing walls and roads.
  • While not the most flexible due to its low lime concentration, its strength is worth it.
  • Best suited for below-ground construction for enhanced stability.


4. Type K Mortar

Venturing into the world of historic or ancient buildings, one quickly realizes that not just any mortar will do. Here, Type K mortar makes its entrance.

Specifically crafted for restoration projects, it’s not commonly used in new constructions but shines brightly when reviving the old. With a notably low compressive strength of about 75 psi, it doesn’t intimidate or overshadow the existing masonry.

Features of Type K Mortar

  • It’s the go-to for restoring historic or ancient masonry structures.
  • Its softness ensures it doesn’t overpower the original masonry.
  • While not suitable for new projects, its expertise lies in complementing what already exists.

5. Type O Mortar

In the world of interior constructions, especially those non-load-bearing walls above grade, Type O mortar emerges as a reliable contender.

With a compressive strength of around 350 psi, it’s not as robust as its counterparts but excels in its specific domain. While its strength might be limited, its ease of application makes it a favorite for repairs.

Features of Type 

  • Perfect for interior, above-grade, non-load-bearing applications.
  • It offers a balance of strength and ease, making it apt for repointing and repair tasks.
  • While its structural capacity limits its exterior use, especially in windy regions, it’s a star for indoor tasks

Choosing the Right Tile Adhesive

When it comes to floor tiles, it is important to choose the right tile adhesive. Tiles that last a lifetime require the right foundation. The main and commonly used contenders here are thinset mortar and epoxy mortar.

These two have distinct properties making them suitable for various tile applications. Let’s have a look at what these offer and which ine is best suited for floor tiles. 


1. Thinset Tile Mortar

Thinset is primarily made of Portland cement, silica sand, and agents that retain moisture.Often mistaken as just mortar, thin-set is actually an adhesive cement that doesn’t contain lime.

Its unique composition includes cement mixed with materials like epoxy, creating a bond that resists heat and moisture. When talking about its consistency, think of a smooth, slippery mud.

Where and when to use it?

For both indoor and outdoor applications, thinset is typically the go-to. This includes common high-moisture areas like showers, kitchen backslashes, and countertops. It is also ideal for surface leveling.

If you’ve got a floor that’s slightly uneven or walls that need a bit of smoothing, go for thinset. However, it’s not recommended for drastically out-of-level surfaces.

Moreover, given its resistance to moisture, it’s perfect for wet areas like shower floors, walls, and bathtubs.

Click to learn: Tips for choosing kitchen tiles

Types of Thinset

  • Standard Thinset: It’s a dry powder that you mix with water. Once mixed, it begins setting, so it’s a use-it-or-lose-it deal.
  • Premixed Thinset: Ideal for the DIYer, this comes in a tub and is ready to apply. Great for smaller spaces like bathrooms. However, for larger projects, the dry mix is more cost-effective.

Working with Thinset

Its robust bond resists moisture and mold, and it remains stable in hot temperatures. Moreover, it doesn’t shrink or contract, ensuring a consistent finish.

For added strength, consider mixing it with a latex additive, especially if there’s a risk of cracking.

2. Epoxy Tile Mortar

This is the second type of mortar commonly suggested for floor tiles. Unlike thinset, epoxy mortar isn’t cementitious. It’s composed of two or three separate components that you mix before use.  It sets faster than thinset, letting you grout the tile in just a few hours.

Where and when to use it?

Epoxy mortar is excellent for porcelain, ceramic, glass, stone, metal, mosaic, and even pebbles. If you are looking to install rubber flooring or wood block flooring, Epoxy’s got you covered.

Moreover, it’s impervious to a broad spectrum of chemicals, making it perfect for certain industrial applications.

Working with Epoxy

It boasts a high mechanical strength, ensuring tiles remain in place. Moreover, installation requires specific temperatures (between 60 and 90 F). Remember, warmer conditions speed up curing, while cooler ones delay it.

However, it is important to note that Epoxy also has its drawbacks. It’s pricier than thinset, has a distinct smell while curing, and sets very quickly, giving you a limited time for adjustments.

3. Tile Grout

Tile grout is also used for floor tiles along with thinset and epoxy. Grout essentially fills the spaces between tiles, reinforcing their bond and preventing chipping. It’s generally made up of enhanced Portland cement and, depending on the type, fine sand.

Mixing and Application

To make your grout, use a 1:2 ratio of Portland cement and sand. If you have a pre-mixed powder, a 1:1 water to powder ratio works best. Professionals often add sealers to boost resistance against moisture and stains.

Which Option is the Best?

For exterior walls and floor tiles, thinset mortar is often the preferred choice due to its water resistance and strength. It’s versatile and can handle the environmental challenges these areas face.

However, it’s always essential to consider the specific conditions and requirements of your project when making a choice. 

Click to learn: A detailed insight on choosing the right tile for your project


Now, as you have seen, choosing the correct type of mortar is not an easy task. It requires a detailed understanding of different mortar kinds and their specific applications.

Whether you are reconstructing your home’s exterior walls or laying down floor tiles, the foundation is important. Mortar is the main ingredient, which makes or breaks the foundation.

By understanding the details of various mortar types and their respective applications, you’re not just building for today but ensuring stability for the future as well.

If you have any other questions, you can click here to contact us at George Ceramics, and we will have professional staff to answer your questions.

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