A relatively common issue with a fireplace is the damage caused to brick from heat. Loose bricks can be a tripping hazard and make your fireplace look old, worn out, or unsafe. This article will discuss how to replace damaged bricks in a fireplace – without removing the entire brick facade – using an easy-to-use product known as Fireplace Mortar.
Fireplace mortar is a soft refractory material that cures hard when exposed to high temperatures. It has been used for decades by masons and chimney sweeps to repair firebox brickwork that has been damaged by excessive heat exposure. Before starting DIY job you must have in mind you have complete knowledge about masonry repairs. If you don’t know then always call your nearest fireplaces masonry repairs to perform this job. But if you have enough knowledge then follow the below guide to repair fireplace bricks.
What You Will Need
- 1 bag of fireplace mortar mix (found at hearth & home stores)
- 1 small bucket of water (to mix mortar)
Tools:
- Rubber Gloves (chemical resistant)
- Cordless drill with drill bits for brick and mortar
Remove Damaged Bricks
Remove all loose bricks first. If there are any bricks that are still solidly attached, you can leave them in place during this process. Using the cordless drill, remove the mortar around the damaged brick(s). You want to get down about ¼” below the full extent of damage so it has space to fill. However, you do not need to dig out every single bit of old mortar because this will create a mess.
Apply Mortar Mix & Tap Bricks
Mix the bag of mortar with water in a small bucket (per manufacturer’s instructions) for two minutes. Using your rubber gloves to keep clean, scoop mortar mix into the cavity using either your gloved hands or an old brick. Do not use new bricks for this purpose! Tap each brick down firmly against the one below it. These bricks will act like shims to fill in uneven spots and create a flat surface on which you will apply the next layer(s).
Apply Fireplace Refractory Cement
Using your cordless drill fitted with a paddle mixer attachment, mix refractory cement at a ratio of 2 parts cement to 1 part hardener according to their instructions. (You can also mix in a separate bucket and then scoop into the cavity, but we found this to be much messier.) The refractory cement is thick enough that it will not run out of the cavity. It cures very fast, so you only need to apply a thin layer (about 1/16″ thick) using your gloved hands or an old brick. You may want to use a small wooden dowel rod instead of your fingers for better accuracy.
Smooth Out Surface & Allow Cement to Cure
Using a wide putty knife, smooth out the surface once it has fully cured for 24 hours. Do not forget to wear your rubber gloves while touching this material! As mentioned before, because these bricks have shims between them, they will create gaps and leave a rough surface. You can take an old brick and use it as a sanding block to smooth out the mortar joints on your fireplace. The refractory cement holds up to high temperatures very well, so you should not need to do this step (and risk touching it) more than once every few years.