Few things are more rewarding than completing a home renovation project, and a fireplace mantel is one fireplace remodel idea that you can admire each time you sit down in your living room. Rather than opting for a prefabricated mantel kit, you can build your own mantel using lumber and molding. Just gather the right tools, and we’ll walk you through the steps to build a fireplace mantel.
How to Build a Fireplace Mantel in 5 Steps
Create a one-of-a-kind look for your fireplace using simple woodworking tools
Photo: Kristen Prahl / iStock / Getty Images Plus / Getty Images
Photo: Kristen Prahl / iStock / Getty Images Plus / Getty Images
Written by Kate Fann
Contributing Writer
Updated August 15, 2023
Difficulty
Intermediate
Perfect for handy homeowners.
Time to complete
10 hours
Including drying time for adhesive. If painting or staining, allow an additional 24 hours of drying time.
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What you'll need:
TOOLS
- Miter saw
- Measuring tape
- Stud finder
- Level
- Nail gun
- Paintbrush
SUPPLIES
- 1-inch by 10-inch pine boards
- Crown molding
- Shoe molding
- Baseboard trim
- Astragal molding
- Wood glue
- Construction adhesive
- Finishing nails
- Sandpaper
- Painter’s tape
- Heat-resistant paint or stain
- Plastic sheets
- Safety glasses
Measure and Create a DIY Fireplace Mantel Plan
Use a measuring tape to take dimensions of your existing firebox or fireplace area. This will help determine the cuts you need to make to your lumber. Sketch a design on paper once you have your measurements and an idea of what you want. Browse fireplace mantel designs online for more inspiration.
A key consideration is the depth of the mantel shelf. If you’re unsure of how deep to make it, but you plan to place decorative items on it, consider a six-inch deep mantel for ample space.
To ensure your design meets national fire safety codes, you need to leave at least six inches between your mantel and firebox on all sides, plus one inch for every one eighth of an inch your mantel sticks out from the wall. It’s a good idea to create a cardboard template of your design to test how it will fit in your space.
Cut Your Lumber
Based on your measurements, use your miter saw to cut the 1-inch by 10-inch pine boards to length for each of the following:
Mantel shelf: The flat piece rests on top of the mantel and runs its width.
Mantel face: The front of the mantel parallel with the opening of the fireplace.
Mantel underside: The opposite side of the shelf.
Mantel ends: The pieces bookending the mantel.
Use your miter saw to cut edge pieces of lumber for each side. When making the cuts, be sure to cut against the grain of your wood. Sand all of your wood pieces with sandpaper to create a smooth surface that will make painting or staining easier.
Assemble the Mantel
Photo: LOOK Photography / UpperCut Images / Getty Images Plus / Getty ImagesAssemble the mantel into a rectangular shelf. Affix the edge pieces to the mantel face using your wood glue and nail gun. Then, attach the underside piece with the same materials.
Using your stud finder, locate your studs so you know where you can securely attach each end side to the wall. If you’re attaching your mantel to a tile or stone wall, you need to use construction adhesive instead of nails.
Before nailing, place your level atop each end to ensure that they will create a level surface to support the mantel shelf. Run beads of construction glue along the entire length of each edge that makes contact with the wall. Then, use your nail gun to nail your mantel to the wall at an angle.
Finally, attach the mantel shelf to the rest of the mantel by nailing it through the top.
Add Trim and Molding
Give your mantel an elegant, finished look by adding decorative molding to each piece. Attach molding by running a bead of wood glue along the mantel's edge. Then secure it in place with your nail gun. You’ll need different molding styles for each part of your mantel, including:
Crown molding: Top of the breastplate and legs, underneath the mantel shelf
Baseboard trim: Bottom of each leg
Astragal molding: Bottom of the breastplate
Shoe molding: Edges of the mantel shelf
When cutting molding to length with your miter saw, make cuts at a 45-degree angle, so perpendicular accents fit together flush in the corners. Review your saw owner’s manual for specific instructions about the settings required to make an angled cut. You may need to use wood putty to cover visible nail heads and create a smooth finish on all trim pieces.
Finish Your Mantel
Once your mantel is assembled and fully sanded, you can apply paint, stain, or another finish to complete the project. Learning how to paint your fireplace is easy if you know where to start. Heat-resistant paint is best to withstand the high temperatures from your fireplace.
Start by lining the area around the mantel with painter’s tape and laying plastic sheets on the floor to avoid getting paint on walls or floors. Apply one or more coats of paint or finish to the mantel according to the instructions on the container, then allow 24 hours for the mantel to dry.
Fireplace Mantel Installation Methods
The process of attaching a fireplace to a mantel will vary slightly depending on the type of fireplace in your home.
Traditional Brick or Stone Fireplace
To install a mantel shelf on a brick or stone surface, start by using a stud finder to identify the wall studs. Make pilot holes at the desired height and align the shelf with them. Use screws that are long enough to give the shelf a firm attachment. Wood screws will work for a wood mantel shelf while masonry screws are recommended for stone mantels.
With some masonry fireplaces, you may need to attach the mantel to the material rather than directly into the wall studs. In this case, use French cleats instead of screws for a secure placement. If you have a concrete over brick fireplace, this method will be your best option.
Drywall or Plasterboard Fireplace
The process for attaching a mantel shelf to a drywall or plasterboard fireplace is the same as a traditional fireplace. Wood screws should be used to affix the mantel.
Electric Fireplace
Most electric fireplaces come with manufacturer-specific mantel shelves or mounting brackets designed to be compatible with their units. Follow the manufacturer's instructions for installing the mantel shelf or mounting bracket. Typically, you'll attach the mounting bracket to the wall using screws and then place the mantel shelf on top of the bracket.
Gas Fireplace or Insert
Similar to electric, gas fireplaces often come with specific mantel installation guidelines provided by the manufacturer. Follow the manufacturer's instructions carefully to ensure proper installation. It should be noted that some gas fireplaces may not be suitable for attaching a mantel shelf, so verify compatibility before moving forward with installation.
DIY Fireplace Mantel Makeover vs. Hiring a Pro
The total cost to build and install a mantel as a DIY project will depend on the type of wood and trim you purchase. On average, you’ll need about $100 worth of supplies and pay an additional cost to rent or purchase the necessary tools. A finishing nailer rental is about $30 per day, while a miter saw rental is about $50 per day.
Professional installation can range in price depending on the quality of the materials used and the complexity of the design. A comparable simple painted wooden mantel may cost $800 to assemble and install, but combined costs for custom mantel design and installation labor can total $6,000 or more. Reach out to a local fireplace installer for an estimate.
Frequently Asked Questions
There are fire codes for a fireplace mantel made of wood or other combustible material. The mantel must be mounted at least six inches away from the fireplace opening on all sides with a non-combustible material—like stone or brick—installed between the mantel and fireplace. Building codes and regulations will vary based on your location, so before beginning the project, research the requirements in your area.
You can use most types of wood for a fireplace mantel. You can use simple veneer plywood. If you prefer solid wood, pine is an affordable option that's easy to cut and finish. Walnut is harder, heavier, and highly durable with a rich dark brown color. Hickory offers a lighter color but is similarly durable. Cedar is ideal for a rustic fireplace design.
In most cases, you should not put a TV on a fireplace mantel. The minimum width required to put a TV safely on a shelf or mantel is 10 inches, but pre-made mantels are usually too shallow, averaging at only seven inches deep. If you do choose to place a TV above a mantel, it should be mounted to the wall. However, do so cautiously as heat radiating from the fireplace could potentially cause damage to electronics.
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