Guide to Building a Fireplace Mantel

In many homes, the central living space is found in a family room setting with a fireplace as its focal point. Stretched across the top of the fireplace is often a fairly hefty piece of woodwork called a mantel. The wonderful thing about a mantel piece is that it doesn't have to look any certain way.

Any creative flair that you might be able to give it will only increase its unique qualities and help it to define your home as your own. You may have seen mantels covered with intricate designs, carvings and moldings that were breathtaking in their complexity.

You have probably also been in homes that were trying to create a more rustic feel, where the homeowner has simply elected to hang an old barn beam over the fireplace. Both styles complement the rooms in which they hang and speak to the tastes of the homeowners.

As you begin to design the mantel that you feel will fit best your tastes and the style of your home, keep in mind that there are two primary ways to construct a mantel. The first is one that hangs on the wall, or even on the stone façade that makes up your fireplace. If you think this is the way you want to go, then you need to make sure that you have the correct structures in place to support the weight, as a mantel is often very heavy.

If you have a drywall surface over the fireplace, make sure that there are studs placed in adequate locations that will allow you to mount the mantel directly to them. If you have a masonry fireplace, there should have been blocks of wood mortared into the stone work at an appropriate height for a mantel. If you are having a new stone fireplace constructed, insist that your contractor put these blocks in place, as they will serve as the mounting blocks for your mantel.

The other style of mantel that you might consider building is a free standing mantel. This is a unit that has legs on the ground, with the actual mantelpiece spanning the legs over the top of the fireplace. While the unit does not actually stand free - it will be secured to the wall - they are sometimes built as free standing units and attached later.

We will discuss here how to build a unit that is actually built out from the wall. Before we begin with specific instructions, let's take a quick look at some of the tools and materials that you'll need to have on hand to do the job. As with any project that requires some detail work, you will find that making a good plan will save you a lot of headache in the end.


  • Miter Saw: The miter saw will be necessary to cut the stock to length and to cut the angles for the mitered joints on your decorative trim work.
  • Brad Nailer/Finish nailer: A pneumatic or battery powered nailer is by far the fastest and easiest way to do finish carpentry work.
  • Sandpaper: This will be necessary for sanding smooth the hole filler that you use to cover the nail heads.
  • Nail Set: A nail set is needed to make sure all of the finish brads and nails are set below the surface of the wood. This will allow them to be properly filled and sanded.
  • Hammer: You will need a hammer to use with the nail set.
  • Cordless Drill/Driver: Whether you are hanging the mantel over the top of the fireplace or securing a free standing one, some very heavy weight screws will be needed. A cordless driver is a much easier way to sink big screws than doing it by hand.
  • Paint Brush: You'll need an applicator for your finish of choice, whether it be paint, stain or varnish.


  • 1 x stock: These pieces will serve as the base of your mantel's surround. Widths and lengths will be determined by the design that you have created. Make sure that you get about 10 percent extra of the total linear footage, as you may have to compensate for cut offs and mistakes. You also need a length of this stock to rip for the top shelf of your mantel.

  • Moldings: What you choose to buy here is completely dependent upon your design and tastes. As with the stock pieces, make sure you add a little extra. Here are some common moldings that are used to build up a fireplace mantel and surround:
    • Fluted Casing: This is often used on the legs.
    • Quarter Round
    • Crown/Cornice Molding
    • Cove Molding

    Take a trip to the home improvement store with your design in hand. Look through the available moldings and do a little creative dreaming while you look. You may be surprised at the selection of styles and designs of moldings that are available. Use this trip to finalize what pieces you want to use to build up your mantel and how much of each kind you will need.

  • Wood putty: Wood putty will be required to fill nail holes. This is a vital step in creating a professional finish.
  • Heavy Screws: You will need these to mount the mantel; nothing shorter than 3" is necessary.
  • Stain/Varnish/Paint: Choose your finish based upon what the rest of the woodwork in the room looks like. Your best bet is to make them match.

Constructing the Surround

As we discussed in the design phase, installing the flat part of the surround is the first step in building the mantel. Using pieces of the 1" stock, attach them to the wall with the heavy screws. Try to drive the screws in a place that will later be covered up by your decorative molding. This will prevent you from having to fill holes when you finish it.

Once the surround is secured, begin to build up the molding according to your plan. As the molding stack continues to grow, do your best to place nails in places where they will be covered up.

If you are using a crown or cornice piece as part of your mantel and you don't have any experience with them, you may want to buy a little extra so you can practice getting the cuts right. It can be a little tedious the first time you do it, and you wouldn't want to be frustrated by ruining your big pieces as you try to install them on the mantel.

Once your surround is complete and you have filled all of your nail holes, it's time to apply the finish. Whether you paint, stain, or varnish, make sure you use a high quality product, as the heat from your fireplace can be very hard on the wood. You'll want to get the best finish available to protect your creation.

Looking for a new fireplace, fireplace fender, accessories or more? Compare types, brands and prices with our Fireplaces Buyer's Guide.