How to Mortar Firebrick

You can build your own fireplace with brick and heat-resistant mortar.

If you are building a fire pit or fireplace out of firebrick, brick that resists the heat of fire, you need to place mortar in between the bricks to hold them in place. The mortar needs to be at least as heat-resistant as the bricks to keep them from getting too hot and cracking. According to Traditional Oven.com, you should apply the mortar no more than 1/4 inch thick so it won't shrink when it cools and cause the bricks to move.

Things You'll Need

• Heat-resistant mortar
• Bucket
• Trowel

Instructions

1. Mix the heat-resistant mortar powder with enough water to give it the consistency of peanut butter.

2. Spread a layer of mortar about ¼ inch thick with the trowel. Use the trowel to even out the layer so it's flat.

3. Lay the firebricks on the mortar and spread a thin layer between the bricks if there's a gap. You don't need any mortar if there isn't a gap.

4. Spread a ¼-inch layer of mortar on top of the bricks and lay a new line of firebricks over the first. Be sure to center each brick over the two bricks beneath it. Repeat the process of mortaring and bricklaying until you have the fireplace or fire pit you want.

References

• Heat Stop Refractory Mortar: Firebrick Mortar
• Traditional Oven.com: Refractory Mortar and Wood Fired Ovens