How to Build a Cement Fireplace Mantel

What You'll Need
2 core 8 by 8 by 16 inch units or 3 core 8 by 8 by 16 inch units
Steel sash unit or wood, single bullnose, capping or header unit

Building a cement fireplace mantel can be a complicated process, but the results can be stunning. Unlike a wooden mantel, a cement fireplace mantel has longevity and is more resistant to smoke and other damages that could be caused from the fire. Also, a cement mantel has high potential for modification. Any type of modification and decoration can be done even after the cement mantel is made and has been fit into place. This step-by-step guide will teach you how to build a cement fireplace mantel. The tools and materials required for the job are given below: 

Step 1 – Draw a Sketch 

This should include the type of design you want and should have all the dimensions labeled. You should decide how high and wide you want your mantel to be. This sketch should have appropriate dimensions to represent all of that so you can refer to it during the job. 

Step 2 – Measure the Wall Area 

After you have a sketch at hand, measure the wall area and apply the sketch to the wall. This includes marking measured areas for the mantel legs’ height and width, the hearth, etc. Once you have done that, you can start working on making cement blocks that you will use to make the mantel. 

Step 3 – Pay a Visit to Home Depot, Ace or a Similar Place 

Take your sketch and your wall measurements to the store. The store will help you calculate the number of bricks and cement you will need for the job. Once you have that calculation, purchase the bricks and cement for your project. 

Step 4 – Get the Corners for the Mantel Legs Ready 

You have to first pound stakes into the wall where you plan on fixing the mantel legs. Then string a line from one corner to the next and use a plumb bob to check if the corners are level. 

Step 5 – Lay the Corners First 

Lay the corner bricks onto the wall measurement. This will help you build straighter legs for the cement mantel around your fireplace. While laying the bricks, smear them with mortar using a trowel. Smear mortar all over one brick so that you can lay the next brick on top of it. Keep connecting bricks on top and to the sides until you get the desired height and width for the mantel legs. Use the trowel to scrape away any excess that is applied.  

Step 6 – Continue Building the Mantel 

Once you are done with first the corners and then the complete legs, install the hearth or the top of the mantel, on top of the legs. 

Step 7 – Finish the Job 

Once you have installed the mantel legs and the hearth that was previously cut to size, cover the whole installation with plaster. Let the finished mantel dry for at least 2 days before lighting up the fire.