How to Install a Wood Fireplace Mantel (Mantle)

The call usually goes like this. A potential new customer calls and says, “I am looking for a mantel. The stone guys are coming tomorrow, and I need something today so they can put it in. Can you cut me a mantel?”

The answer, of course, is yes. However, I spend a little time calming them down and explaining that they are going to mount the mantel after the stone work is done, how it will come out beautifully and how not having a mantel right now won’t slow anything down.

Most people expect that the wood is going to be embedded in the stone, which is the reason for all of the last-minute, frantic calls, but I argue that the wood should not be surrounded by stone, mostly because of wood movement and not because of the fact that they don’t have any wood to surround with stone.

This mantel was milled from a piece of driftwood and the fresh cuts were stained to match the gray exterior.

Install solid wood mantels in front of the stone. Don’t leave a void or do anything different to the stone. 

All wood, dry or wet, moves with seasonal changes and the stone does not. This means cracks will develop around the mantel over time. They will be small, perhaps unnoticeable, around dry wood, but if the wood is newly sawn and installed wet, the cracks will be unsightly after the wood has dried and shrunk. The other possibility is that green wood could bow, twist, or warp in some fashion and blow things apart. If a 8″ x 11″ x 8′ long piece of white oak decides to move aggressively, there may be little that can stop it and the results could be catastrophic. It is definitely possible that any stone or brick veneer could be popped from the wall when the wood starts moving.

So, I say, don’t fight it. Don’t try to put the stone around the wood. Let the stone guys do their thing, step back, take a deep breath and then find a cool piece of wood to install in front of the stone.

The method I recommend works for installing any solid wood mantel above any fireplace, from drywall to stone and anywhere in between, and the process is quite simple.

Besides your tools and the actual piece of wood for the mantel (purchased, of course, from WunderWoods) you will only need 5-minute epoxy and two steel stakes. I get the steel stakes at Home Depot in the concrete supply aisle. They are 5/8″ thick steel stakes used for concrete forms and they are very sturdy. Do not use rebar because it is too flexible.

You might be thinking that just two steel rods aren’t enough and be inclined to use more, but don’t, unless it is absolutely necessary. Two 5/8″ thick stakes can easily hold 200 pounds (which I usually verify with a modified one-handed pinky pull up in which my knees stay on the ground), and I have found that even with more than two stakes, the heavy lifting is usually done with just two, while the others are just along for the ride. And, since the extra stakes just make for more drilling and more chances for things to not line up, I say don’t use them. If you feel that you need to beef things up, just get bigger steel rods.

The basic premise of this method is that you are installing two shelf brackets in the form of steel rods that will support the mantel which will have two holes drilled in the back to accept the rods, all of which will be hidden.

Start by determining the mantel location and then finding suitable places to install the rods. The rods need to be mounted solidly, either through the wood framing or through the stone, or both if possible, and close to each end of the mantel. Usually the exact locations are determined by the stone or framing layout.

Drill the holes in the fireplace surround with a 5/8″ masonry bit and a hammer drill in stone or brick, or a 11/16″ bit and a regular drill in wood. The 5/8″ bit in stone will usually leave a hole with enough room for level adjustment because the hammer drill makes a roomier entrance. Since wood drills easily and with a cleaner hole, the 11/16″ bit is required to allow for level adjustments.

Drilling holes for mantel rods

Drill a hole in the fireplace surround for the metal stakes.

Next, you will need to drill 1″ diameter holes as deep as possible in the back of the mantel that line up with the rods (be careful not to drill all of the way through). I usually just measure for the locations, but if you are worried about messing things up, you can make a drilling template to use on the wall and the back of the mantel. This still doesn’t eliminate screw-ups (nothing does) because it is easy to flip the template when you should have flopped it. Be sure to mark your template with top, bottom, left and right sides, and don’t forget to mark the side that faces the mantel and the one that faces the wall.

Drilling mantel for rods

Drill 1″ holes in the back of the mantel. Use a square to keep the drill bit lined up.

Next insert a steel stake into each hole and secure it with 5-minute epoxy. Be sure to fill in the front and back for full support. While the epoxy is setting check the rods for level and adjust as necessary. I often add some small wedges to help hold things level while the epoxy is setting up. After the epoxy is set up, trim the rods to the final length which is determined by the depth of the holes in the back of the mantel.

Fill the hole and cover the steel stake with epoxy to make sure it is fully supported.

Fill the hole and cover the steel stake with epoxy to make sure it is fully supported.

Site across both stakes to make sure they are parallel with each other.

Site across both stakes to make sure they are parallel with each other.

In a perfect world you would slide on the mantel and be done at this point, but it is rarely the case – often you will need to make some small adjustments to compensate for drilling by hand. If the mantel doesn’t sit level it can be adjusted by adding wraps of tape to the metal stakes, either near the front or back, depending on which needs to be raised.

Use wraps of tape to make level adjustments to steel stakes.

Use wraps of tape to make level adjustments to steel stakes.

Once you have the mantel sitting level you are done. Don’t worry about gluing it on – it isn’t necessary and will only make the mantel more difficult to remove if you need to work on it in the future.

The finished product.

The finished product.

 

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About wunderwoods

Hi! My name is Scott Wunder and I am the owner of WunderWoods Custom Woodworking. We build wine cellars, built-ins and furniture from local woods, here in St. Louis, MO. Recently, I finished a three-year term as the President of the St. Louis Woodworkers Guild, which had me writing a monthly article for our newsletter. I love to write, especially about wood, and found that I still had more to say. Every day I run into something wood related that I realize some of my customers don't know and this seems like a great forum for sharing what I have learned (instead of telling the same story to each person). The main thing to remember is that I try to keep it light and as my wife always reminds people that have just met me, "He is joking."

30 responses to “How to Install a Wood Fireplace Mantel (Mantle)”

  1. Jesse says :

    This is a great post. Thank you. How would you approach the project if the stone wall for the fireplace area was not flat?

    • wunderwoods says :

      I would need more information on what part wasn’t flat. If you have any specifics, I would be glad to address them.

      • Rick says :

        For example if it’s brick. I guess all you can do is let it be where it wants to be. If there is a slight gap, there isn’t much you can do.

      • wunderwoods says :

        If there is a big gap you can either chisel out the back of the mantel or chisel off the high spot in the brick. Both are easy to do. A gap between the mantel and brick needs to be quite large before it looks unsightly.

  2. Chris in TX says :

    Great post. I’m in process of doing just this with limited construction knowledge. I drilled 5/8″ holes thru stone 6″ deep using hammer drill but can’t tell what (wood or metal) is on the other side. Is 6″ enough? The mantel I’m using is 13.5″ in width at it’s widest point (12″ avg). Also, the concrete stakes won’t go into the hole. 😦 When I got the stakes at HD, they all had the same diameter so I presume it’s a standardized diameter so not sure why they won’t go other than the obvious. Guess plan tomorrow is to buy bigger bit and try again unless you have better option.

    • wunderwoods says :

      Usually the hole drills bigger in stone because of the vibration and more accurately in wood. A slightly bigger bit will be the answer if the stakes aren’t going in. The void will be filled with epoxy, so it will be fine as long as you can get the stakes in. 6″ is more than enough depth.

  3. Scott Shaff says :

    What is the best way to trim the steel rods to their final length after you set them?

    Thank you,
    Scott

  4. John Morris says :

    Great post, thanks. Two questions:

    (1) I have a 5’X6″X10″ rough-hune beam (salvaged from a 1750’s home), which is very heavy. It looks very similar to the mantle in the first picture on this page. Are you confident that two steel stakes are sufficient? I think so, but just want to ask if you ever feel the need to use more.

    (2) For mounting in masonry, would you locate the holes in the mortar joints or in the limestone?

    • wunderwoods says :

      After installation, I usually hang on each stake to make sure they will hold me up. I tip the scales at a dainty 200 lbs., so I feel confident that two stakes can hold up to 400 lbs. Most mantels aren’t anywhere near that heavy, and I don’t think yours is over the limit. There is no reason that you can’t add a third if it makes you feel better, but it will make installation a bit more tricky. You can drill in the mortar or rock, but the mortar is easier to drill.

  5. Lori Camblin says :

    Scott, this is a great article, however, what would you recommend if I am aiming to replace a limestone ledge already on my stone surround? There are also two protruding stones forming a “corbel” on each side under the ledge. Would a mason be able to remove those and then mount the reclaimed beam. I want badly to replace this and put a darker wood beam up to warm up the hearth. Thanks so much, Lori

  6. Patrick lynch says :

    Why is it necessary to drill the corresponding holes in the mantel at 1″ diameter?

  7. Shari says :

    I believe the stone on my fireplace is not real stone. My husband is afraid the weight will crumble the stone and I am not able to locate the studs behind the stone to use those as more support. Any suggestions? I am using a 2×4 brace and a mock beam made out of pine so the weight is considerably less than a solid piece of wood but I’m still nervous about how to hang it.

    • wunderwoods says :

      The good news is that there is some sort of structure holding up your fireplace and since you are putting up a mantel that can cover lots of test holes you have plenty of chances to find studs. They are usually 16″ on center, so you should be able to find one after drilling only about 16 holes. Drill the first one about 16″ from the edge and maybe you’ll get lucky.

  8. Jeremy Deichman says :

    Do you drill all the way thru the 2 x 4 to install the stakes?

  9. john doherty says :

    Hi Scott, after reading this I think i have the courage to proceed 🙂
    I have a 7ft x 9″ x 3 1/2″ mantel shelf (55 lbs) with two solid wood corbels 6 1/4″ deep (5 1/2 lbs each). It’s going on a concrete wall that is fronted with studs and plaster. I was thinking of using your technique but using lag or coach screws (cutting the heads off when in position). I’m using one in each corbel (1/2″ x 9 1/2″ screws)… and with the beam sitting on the corbels – two more screws joining beam to wall (1/2″ x 8″ screws).
    Do you think I need to go through the studs? I thought as long as I get to the concrete blocks i’d be ok…?
    Do you think I need to use epoxy in the wall if I’m screwing into it? I notice you don’t put any in the beam which would mean I wouldn’t be using any at all…?
    Any help would be much appreciated.

    • wunderwoods says :

      The method I show is for a floating mantel. If you are using corbels, they will do most of your work. You will, of course, still need to mount the corbels. They can be mounted as you described and then just screw down through the mantel to attach it to the corbels. Just the studs will be more than strong enough to support the mantel since it isn’t too heavy.

      • john doherty says :

        Thanks Scott…. all worked out well. I attached the corbels using your method and laid the mantel onto of them attaching with a 5/8″ wood dowel in each. It all seems very solid and safe. Thanks very much for the help!

      • wunderwoods says :

        I just use loctite epoxy from Home Depot. It comes in two bottles, one resin, one hardener and is thick-bodied.

  10. Charles R Mills says :

    What kind of epoxy do you recommend? I am using the steel rods in a 2×4 stud through drywall.

  11. Pete D says :

    Nice article. I have a wood mantle slab that is 5′ long, 4″ thick, and 13-15″ in depth. It is very heavy, at least 70-80 lbs of white oak. We are mounting it on drywall. Will two studs at each end suffice for this? And any idea how thick studs are in a house built in late 90s? I’m trying to figure out the proper length needed for the steel rod. My guess is at least a foot.
    Thanks!

    • wunderwoods says :

      One steel rod on each end is enough for that mantel. Studs are 3-1/2″ thick. Make the holes in the mantel as deep as possible without going through the front and trim the rods to the appropriate length after they are in the wall. Start with 18″ rods.

      • Pete D says :

        Thanks for the response! Couple more questions: I’m guessing that a threaded steel rod is OK?
        My hardware store does not have a 11/16″ drill bit. I picked up a 5/8″ drill bit for drilling into the wood. Do you think this can still work?
        I do not have a grinder saw, only a hack saw for trimming the steel rod. I am hoping it will not take too long to saw through it.

      • Rick says :

        You want the holes in the wall and the holes in the wood a little bigger than the rod (and yes threaded rod will work).

  12. wunderwoods says :

    Threaded rod will work if it is stiff enough. Put some pressure on it and see how much it bends. If you need to, go to a bigger size. Main point was not to use rebar, it is very flexible and the stakes I recommend are very stiff. A larger hole won’t hurt. You will just need to use more shims or epoxy in the hole. A hack saw will work fine. It isn’t as fast as a sawzall, but it will get the job done.

    • Rick says :

      I think you would agree that the use of rebar depends on the weight of the mantel you are hanging. I’ve hung 60lb mantels on two 6 inch rebar rods with zero problem. Would probably take 300lbs or more to bend a 6 inch pc of 1/2″ rebar. You can use rebar,

  13. wunderwoods says :

    You can use rebar, just make sure it is stiff enough for your installation. The flexibility of rebar becomes more noticeable on mantels that are deeper, in the 12′ range and especially more shelf like, at around 4″ thick. If the mantel doesn’t protrude much from the wall and has a decent height, it will be less bouncy.

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