# Basics of Working with Refractory Mortar and Laying Firebrick

**URL:** https://forums.firespeaking.com/t/basics-of-working-with-refractory-mortar-and-laying-firebrick/363
**Category:** Uncategorized
**Created:** [June 1, 2026, 10:43pm UTC](https://forums.firespeaking.com/t/basics-of-working-with-refractory-mortar-and-laying-firebrick/363 "2026-06-01T22:43:50Z")
**Posts on this page:** 1
**Page:** 1

<div class="post-metadata">

### Author: ![max](https://yyz1.discourse-cdn.com/flex035/user_avatar/forums.firespeaking.com/max/32/5_2.png) [@max](https://forums.firespeaking.com/u/max)
#### Post date: [June 1, 2026, 10:43pm UTC](https://forums.firespeaking.com/t/basics-of-working-with-refractory-mortar-and-laying-firebrick/363/1 "2026-06-01T22:43:50Z")

</div>

Originally published at: [Video Tutorial: Basics of Working with Refractory Mortar and Laying Firebrick - Firespeaking](https://www.firespeaking.com/masonry-heaters/installation-basics/refractory-mortar-fire-brick/)

It is important for someone installing a masonry heater core to be familiar with working with refractory mortar and laying firebrick. For the purposes of our installation instructions, we will refer to the use of commercially available pre-mixed refractory mortars which are typically a combination of clay, very fine aggregate, and sodium silicate (aka waterglass) which helps for this fine, workable clay mortar to airset hard.

### Video 1: Opening and Preparing Your Refractory Mortar

[https://www.firespeaking.com/wp-content/uploads/2026/06/Mixing-Refractory-Mortar-Low-Res.mov](https://www.firespeaking.com/wp-content/uploads/2026/06/Mixing-Refractory-Mortar-Low-Res.mov)

### Video 2: The Basics of Laying Firebrick

[https://www.firespeaking.com/wp-content/uploads/2026/06/Laying-Firebrick-Low-Res.mov](https://www.firespeaking.com/wp-content/uploads/2026/06/Laying-Firebrick-Low-Res.mov)

Remember, when you complete a line:

1. Level
2. Plumb Corners
3. Range

### Caution: Prevent Excessive Efflorescence

Mortars with sodium silicate in them can tend to effloresce (develop a white crystaline structure) when the firebrick maintains humidity over a couple of days. This can stain your work so it is recommended to work as dry as possible and, if sponging, take care to place a fan and/or dryer in front of your work at the end of the day. This is especially important for visible surfaces such as the inside of the firebox and and oven and in working conditions which are cold and humid.