What Is The Best Mortar For Fireplace Stone Slips?

What Is The Best Mortar For Fireplace Stone Slips?

Choosing the Right Mortar for Fireplace Stone Slips: A Guide to Building a Beautiful and Durable Fireplace

Installing stone slips for your fireplace requires careful consideration of the right mortar. The mortar not only acts as an adhesive but also provides crucial strength and stability. In this blog post, we will discuss the different types of mortar and help you choose the best one for your fireplace project.

1. Type S Mortar

For fireplace installations, Type S mortar is a popular choice. This medium-strength mortar offers good adhesion and durability, making it reliable. It consists of a mixture of portland cement, sand, and lime. With its higher compressive strength compared to Type N mortar, Type S mortar is suitable for fireplace stone slips exposed to higher temperatures.

2. Refractory Mortar

If you plan to use your fireplace frequently or have a wood-burning fireplace, consider using refractory mortar. Designed to withstand high temperatures without cracking or deteriorating, refractory mortar is resilient to thermal shock. It is crafted from a blend of high-temperature resistant cement and fine aggregates, allowing it to handle the intense heat generated by the fire which is perfect for fireplace stone slips.

3. Type N Mortar

Another commonly used option for fireplace stone slips installations is Type N mortar. This medium-strength mortar offers good adhesion and workability. Composed of portland cement, lime, and sand, Type N mortar has slightly lower compressive strength compared to Type S. However, it is still suitable for most fireplace applications.

4. Type O Mortar

While generally not recommended for fireplace constructions, Type O mortar can be considered if your fireplace will not be subjected to high temperatures or heavy use. It is the weakest mortar available and has lower compressive strength than Type N. Type O mortar is made from a mixture of portland cement and lime.

Choosing the Right Mortar: Factors to Consider

When choosing the mortar for your fireplace stone slips, keep the following factors in mind:

  • Temperature Resistance: If you have a wood-burning fireplace or plan to frequently use your fireplace, select a mortar with high temperature resistance.

  • Strength: Consider the compressive strength of the mortar to ensure it can support the weight of the stone slips.

  • Workability: Evaluate the workability of the mortar, ensuring it is easy to apply and shape to achieve the desired aesthetic.

  • Instructions: Always refer to the manufacturer's recommendations for the specific mortar product you choose. They provide detailed instructions on the correct application and use of their product.


Selecting the correct mortar is essential for a successful and long-lasting fireplace stone slip installation. Type S mortar is a popular choice due to its good adhesion and strength. However, for higher temperature resistance, refractory mortar is recommended. Remember to consider factors such as temperature resistance, strength, workability, and adhere to the manufacturer's instructions when making your decision. By choosing the appropriate mortar, you'll ensure that your fireplace stone slips not only looks beautiful but also withstands the test of time.

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