What’s a fireplace without a mantel? While building my own fireplace from scratch, I knew a DIY fireplace mantel would take my stone fireplace to the next level. Not only is it perfect for everyday décor, but it also serves as the perfect spot for holiday decorating, especially at Christmas.
In this guide, I’ll show you how I built my oak fireplace mantel from scratch, including a built-in outlet for Christmas lights! Let’s get started.
Why You’ll Love This DIY Fireplace Mantel
Customizable: Make it the perfect size and style for your space. Budget-Friendly: A beautiful mantel at a fraction of the cost of store-bought. Functional Design: Built-in outlet for lights, holiday décor, and more. Rustic Charm: Made from sturdy oak, it looks like a solid beam for a timeless look.
Watch My DIY Fireplace Mantel Tutorial
Prefer a visual guide? Watch my step-by-step video tutorial on how I built and installed this gorgeous DIY fireplace mantel. 
Table of Contents
Tools You’ll Need
Here’s a list of tools I used to build my DIY mantel:
Materials for a DIY Fireplace Mantel
Here’s what you’ll need for this project:
- Oak 1x8s
- Wood glue
- Wood filler
- Stain
- Polycrylic
- Wood screws
- Miter saw
- Table saw
- Painters Tape
Step 1: Building the DIY Mantel Frame
When building my DIY fireplace mantel, I chose oak because it’s both sturdy and beautiful, especially when stained. I wanted the oak boards to look like a solid beam once the project was done.
Using a miter saw, I cut three pieces to the desired mantel length—one each for the top, front, and bottom. I also cut two smaller end pieces.
Step 2: Beveling the Edges
I adjusted the blade on my table saw to a 45° angle to bevel the edges of these boards.
The front piece got all four edges beveled, while the other pieces had only three beveled edges, leaving the side that would sit against the fireplace straight.
Step 3: Assembling the Mantel
Time to assemble this DIY fireplace mantel! I laid them out, beveled edges down, and taped them together for alignment.
After flipping them over, I applied wood glue to all the joining edges and folded the boards into a box.
A brad nailer came in handy to secure the corners, but be careful with the angle—if you shoot the nails in too steeply, they might poke through and then you’ll need to pull them out and fill the holes with wood filler. Trust me, I’ve learned this the hard way!
You want to make the seams disappear when building a DIY fireplace mantel. I did this by gently pressing along the edges with the neck of my hammer.
Step 4: Staining & Sealing
After filling any gaps or nail holes with wood filler and sanding everything smooth, I stained the mantel in Early American, my go-to color for warmth and richness. It’s no shocker that I reached for it when building this DIY fireplace mantel. This is the same color I used on my stair railing and floating bathroom shelves.
Once the stain dried, I sealed it with Polycrylic for a subtle sheen and protection.
Since I wanted an outlet in the mantel, I traced the electrical box on the side. Then, I drilled starter holes big enough for the jigsaw blade to fit in at all four corners of my cutout. Then, I used the jigsaw to cut out the rest of the opening.
Step 5: Installing the DIY Fireplace Mantel
With the mantel fully built, it was time to install it. Since I had built the fireplace in my dining room from scratch, I added a crossbeam during the framing process that would support the weight of the mantel. To further secure it, I installed another 2×4, attaching it through the sheeting to the crossbeam I had previously installed.
This new support beam sat just above the outlet wiring, and of course, I made sure everything was level before moving forward.
Next, I set the DIY fireplace mantel on top of the 2×4 support beam. I fed the electrical wire through the outlet hole, then attached the mantel to the support beam using screws placed near the back. N need to worry about the screws being visible, as the stonework would eventually cover them.
Once the mantel was secured, I wired in the outlet. We are done with building and installing this DIY fireplace mantel!
Final Thoughts on My DIY Fireplace Mantel
After completing the stonework and installing the fireplace insert, I was proud of how everything turned out! This DIY fireplace mantel brings a cozy and inviting atmosphere to my dining room and serves as a stunning focal point.
Want links to anything you see here in my dining room? I have all the details for the decor and more listed here.
Here’s a before photo just so you can see what a difference adding the fireplace made to this room. I have a full tutorial showing you how I built this floor-to-ceiling stone fireplace surround all by myself.
For a durable and classic look, hardwoods like oak, maple, or walnut are great options. Softwoods like pine are more affordable and easier to work with but may be less durable over time.
The thickness of your mantel depends on the style you want. Most mantels are between 1.5 to 3 inches thick, but a chunkier look can be achieved by creating a faux beam using thinner wood.
Yes! For safety and stability, it’s important to attach the mantel to wall studs or a secure support beam. This ensures it can support weight, especially if you plan to decorate it with heavy items.
The height of a mantel typically ranges from 48 to 60 inches above the floor, depending on the size of your fireplace and the room’s ceiling height. For a custom look, consider the scale of the room and how you’ll decorate it.
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