Yes, you can put concrete over a brick fireplace, however, it is not a recommended practice as it can potentially cause longterm damage.

The process of covering a brick fireplace with concrete involves cleaning the surface, applying a bonding agent, mixing and applying the concrete, and finally, smoothing and shaping the material to achieve the desired look.

You should use concrete such as Rutland Castable Refractory Cement for a fireplace to protect the surface from extreme temperatures. Aggregates will include sand, and high alumina cement (HAC), which is made up of calcium aluminates. Its strength is ideal for areas exposed to high heat.

Concrete is a popular way to cover a brick fireplace since it’s contemporary, sustainable, and affordable. It’s also something that you can do yourself with a bit of handiwork. If you’re going with a DIY, make sure to cover up the brick with cement boards prior to applying your concrete.

Making a brick fireplace look like concrete can be done using a few different methods. One option is to use a concrete overlay. This involves applying a layer of concrete mixture over the brick and then texturing it to give it the desired texture.