How to Build a DIY Mantel That Hides Your TV Wires!

worstontheblockMarch 15, 2021

Is your fireplace lonely without a mantle? Want to mount your TV but don’t know what you’ll do with all those wires? Then follow along because BOY do I have the solution for you with this custom DIY mantle that will hold all those messy TV wires — and will look SO GOOD doing it!

The Story…

After whitewashing our brick fireplace, staining the beams, painting the crown molding and putting in a fireplace insert, all I could dream about was adding a mantel.

And mounting our TV above the fireplace so I could replace the TV stand with a love seat.

The dilemma: we were on a budget AND our fireplace is huge. AND what do we do with all those wires? We would not be able to put an outlet into the brick, and I did not want the wires to hang down all willy-nilly.

I scowered craigslist and facebook marketplace for mantels for sale. I thought I would get a great deal and just hang it up there, easy!

I was wrong.

Everything I saw was either too small or way too expensive. Usually both. And I still had nowhere to hang our Christmas stockings.

So I decided that without any experience or proper tools, I would build it my damn self.

Impulsive? Maybe…

The Solution (All About the Mantel)

DIY projects are awesome because you can totally customize them to fit your specific needs.

After a little brainstorming I realized that if I made my own mantel, it would provide the opportunity to make an area inside the mantle to hide the TV wires.

The design for the mantel itself is pretty simple. It’s basically a hollow box to hold the wires on top of a lower supporting box attached to the fireplace for stability.

The wires would come down from the TV, enter the mantel in the center and then could be fed to either side of the fireplace.

The wires would then exit the mantel at the bookshelf, would be fed neatly down to the cable box and further down into the cabinet on the bottom which neatly housed all our electronics out of sight.

The top of the mantel is actually a door on hinges to allow access for running and changing the wires as needed.

It worked out perfectly.

It’s also really nice at Christmas time as I am so easily able to add twinkle lights to my garland, which really amps up the display and “Christmasy” feels without all those ugly wires.

Keep in mind that you could absolutely take this design and use it to create a mantle without the actual fireplace. Just attach the 2×4 support to the wall in a stud and you’re good to go with your faux fireplace.

Below you’ll find the measurements I used for my mantel as well as a guide on how to customize the plan to fit your own fireplace.

Follow along below for step-by-step instructions on how to build your own mantel that will hide all of your electrical cords, too.

To get started…

Measure your fireplace.

Measure first so you can follow the guide below to make a plan that is custom to your space.

This will also ensure you purchase the right amount of wood.

Our fireplace is huge, coming in at 8 feet and 2 inches wide. Most fireplaces are not this big, so measure and find out.

You’ll need the length of your fireplace as well as the depth from the outer corner to the adjacent surface (wall or bookcase).

This depth measurement will be very important later.

If your fireplace doesn’t have any depth or if you plan on mounting the mantel to the wall, it’ll be a few less steps for you.

Shop for supplies.

What you’ll need:

miter saw (a circular saw is fine for most of the cutting but you’ll need this for the crown molding)
jig saw
wood: see below
crown molding (we used 5-1/8″)
panel molding (we used 1-1/4″)
screws & finishing nails
drill & driver
hammer
nail set to sink nails
wood filler
sand paper
concrete anchors
level
tape measure
concrete drill bit
clamps
wire covers (optional)
brad nailer (optional but recommended)
piano hinge
primer
paint color of choice

Wood needed for your mantel:

Support beam:
2x4x(length of fireplace)
2x4x(# feet fireplace +1 x 2″ = # inches extra 2×4)

Support box:
1x6x(fireplace length + 1.5″)
(2) 1x6x(inches fireplace depth + 3-1/2″)
(2) 1x4x(length fireplace + 1/2″)

Supports above support box:
(1) 1x4x(length of fireplace – 2″)
(1) 1x8x(length of your fireplace in inches / 8, then / 1.5 and mulitply by 2.75) = number of 1×8 in inches
(1) 1x4x(depth of fireplace)

First mantel shelf:
(1) 1x8x(length of fireplace + 8″)
(1) 1x4x(depth of fireplace x 2)
(1) 1x1x(depth of fireplace x 2)

Crown molding:
(1) (length of fireplace + 1.5 ft+4″+depth of fireplace)

Top mantel shelf:
(1) 1x8x(length of fireplace + 10″)
(1) 1x2x(length of fireplace + 8″)
(1) 1×5″x(depth of fireplace x 2)

Make a list of the wood required for your build and then purchase your wood in multiples that make sense.

Check out our 8 mistakes to avoid when purchasing wood for some helpful hints.

Build it!

Build the supports.

This will be the base which will hold your mantel to the fireplace.

Cut a 2×4 to the length of your fireplace and cut 2″ sections of 2×4.
To determine the number of 2″ sections needed, take your fireplace length in feet and add 1.

Since our fireplace is 8’2″, I took an 8 foot length of 2×4 to be the horizontal support and cut nine (8+1) 2″ sections with my circular saw.

These can easily be cut on a miter saw if you have one. I did not at the time.

Always read all directions and follow every safety precaution
when using powertools!

Starting at one end of the 2×4 and working your way down, wood glue the 2″ sections to the 2×4 at every foot.

Be careful to ensure that the top of the 2″ sections are even with the 2×4 as this will be what the mantle sits on.

Then using your drill and driver, screw in the supports from the back of the 2×4.

Your support piece is now complete and ready to be mounted to the fireplace, but keep it by your work station for the next step as it is a helpful guide.

Cut wood for lower box.

This will be the bottom-most, visible portion of the mantel. It will slide over the supports and cover the 2×4 completely.

Cut two lengths of 1×4 to the length of your fireplace plus a half-inch for wiggle room.

For me this was (2) 8’2.5″ boards.

Using your 1×6 common board, you’re going to cut a section that will be the front of the box by adding 1.5 inches to the length that you cut for the 1×4’s.

For me this came out to 8’4″.

Note: as this will be the front of the mantel, make sure you choose the best side of the board with minimal knots in the wood. Don’t make my mistakes!

Then cut two more sections of 1×6 which will be the sides of the box. For this you’ll take the depth of your fireplace and add 4″.

For me and my 4″ deep fireplace, this was 8″.

If your fireplace is flush against the adjacent structure (wall or bookcase), just cut the 4″ of 1×6 for both sides.

Secure box.

Now that you have your wood cut, use wood glue to attach the box together.

The front 1×6 will cover the edges of the 1×4’s and side 1×6’s

Then secure it all together using your brad nailer or finishing nails and a hammer.

As you hammer, ensure that all pieces remain flush with each other. The rest of the mantel will sit on this piece so you want it all to be even.

Use your nail set to sink the nails and fill the holes with wood putty. Sand it down when it’s dry to create a nice even surface.

Mount the 2×4.

Grab a buddy!

You’ll need at least one other person to complete this task as both sides need to be supported, you’ll have to level the piece and drill at the same time.

Ensure the beam is in the place you want it. Remember that this is just for the lower half of the mantel (the box you made will slide over the support), so there will be about another four inches of mantel above this support.

Use your concrete anchors to mount the 2×4 and follow the directions.

Using your concrete drill bit, drill your first hole through the wood and brick (this may take some patience. Don’t force it).

Then drill the concrete anchor into the hole you created. Depending on your anchor, you will probably need a hex set to drill in the screw. These often come in drill kits so you probably have it on hand.

At this point you can still maneuver the wood a bit as needed. Make sure the 2×4 is level before drilling your second anchor in as you won’t be able to move it after that.

We used four anchors for this process. It’s not going anywhere!

Create supports above your box.

These supports will hold up the top mantel shelves while also creating the hollow space for the wires.

For the back:

Using 1×4’s, you’re going to create a solid section in the back of the mantel which runs along the fireplace.

***DO NOT attach this piece yet! Just cut and have it ready.***

This piece is going to attach to your first mantel shelf later on.

Take the width of your fireplace in inches, subtract 2 and divide by 2.
This gives you length for each side of the mantel.
Cut two 1×4 boards to this length.

With our 8’2″ wide fireplace, we cut a 1″x4″x8′ in half.

You’ll need about a 2″ space right in the center of the mantel. Don’t forget this space as this is how the wires to slide down into the mantel!

For the front:

For support in the front of the mantel, we cut several sections of wood for support blocks.

To determine the number of supports you’ll need:

Take the width of your fireplace in inches, divide by 8 and then divide that number by 1.5. This will allow for about 4″ in between each support in the front.

This will give you some extra space when you need to access your wires. You’ll appreciate this later– trust me on this one.

Cut your 1×8 into 2-3/4″ pieces until you have the number required.

For the sides:

If your fireplace has any depth to it, you’ll also need to add support to the sides by cutting two lengths of 1×4 to the depth of your fireplace (one for each side).

Attach front and side supports to the top of the box.

Now that you have your supports cut, you can attach the 1×8 sections to the front of the mantel and the 1×4 support to the side using wood glue.

*DO NOT stick the longer 1×4 back pieces in yet, as you first have to attach the box to the 2×4.

Glue and stick the front supports to the top of the box long-ways, (so they stand 2-3/4″ tall). Really press down and make sure it sticks well.

Leave about 4″ between each support in the front.

Here’s a visual of what it’ll look like in a few steps.

Begin painting.

At this point you can paint the lower part of the box (you don’t need to paint the supports as you will not see them).

You can wait until the entire mantel is complete to begin painting as there will be more to do later, but I decided to start painting the box before it was secure on the fireplace.

I’m known to make a mess with paint and wanted to decrease the chance of this happening.

Allow to dry completely.

Secure the box over the 2×4.

At this point you should attach your box to the mounted 2×4.

Simply slide the box over the 2×4, ensure it is snug and level (it should be if the 2×4 was mounted correctly).

Drill a pilot hole with your driver through the top of the box and into the top of the 2×4. Then drill your screw into the pilot hole.

Continue this process all across the top of the mantle, approximately 1′ apart until the box is securely mounted to the 2×4.

Create the first mantel shelf.

This first shelf acts as a fixed support for the upper shelf as well as the place your molding is going to attach to. It be cut with a jig saw to provide the access points to your TV wires in the hollow space below.

Cut a 1×8 that spans the width of your fireplace plus 8 inches

Mine was 8’10”.

First, mark where you’re going to make your holes with a pencil. Make sure the holes will be between the supports you just created.

We made three larger holes, one in the center and two at the corners, and six smaller holes.

The center hole is about 4″x10″ and the corner spaces are about 4″x8″. The smaller spaces are about 2″x4-1/2″ with about 6″ between each hole.

You want to make sure you have enough space to get a hand in there, but you also need enough wood to provide support for the top piece.

Be sure to mark out that 2″ wide space in the middle for the wires to fit down into the mantle.

Cut your access points using your jig saw. Be sure to take all safety precautions and read your tool’s directions completely.

Sand the holes down to avoid splinters!

Attach the back support.

The support you created earlier for the back of the mantel (two 1×4 lengths) can be attached to your (now cut) first mantel shelf.

The 1×4 will lay vertically along the back of the fireplace and the mantel shelf will butt up against your 1×4 back support (see above picture).

Remember to leave those 2″ in the center for your wires to come through!

Wood glue, clamp and nail together to secure.

Attach first mantel shelf and support.

Lay your cut 1×8 with the attached back support on top of the front supports. Align the back support along the fireplace wall.

Measure to make sure that the shelf is even on both ends and attach with wood glue and your brad nailer or hammer and nails to secure.

Cut and attach side pieces.

If your fireplace has any depth to it, you’ll also need a top piece for the sides and a square dowel to support it. If not, skip this step.

Cut two pieces of 1×4 to the depth of your fireplace.
Cut two square dowels to the depth of your fireplace.

Attach the dowels to the just-cut 1×4’s along the depth side, and then glue and nail the dowel into the already-attached 1×4 support on your mantel.

It should be even and aligned with the top mantel shelf.

Cut molding.

This is where you’ll need a miter saw. If you don’t have one (we didn’t), ask a friend that does to help you.

If you’ve never cut crown molding before (I hadn’t), watch a few tutorials on YouTube before attempting. Crown can be expensive and you don’t want to have to do it twice!

**Always follow all safety precautions and read all directions
when using power tools**

Measure your support box from end to end. This will be the measurement for the lowest corner point of the molding.

The measurements have to be exact on the inside corners. Take care here to measure and mark your molding correctly on the very bottom with a pencil.

The molding has to be cut upside down and at a 45 degree angle to the back of your miter saw.

A trick if the molding is too tall for your saw:

Swivel your saw to a 45 miter and then clamp down spare wood to increase the height of the miter “fence”, so that your molding has something to rest on.

Do this BEFORE putting the molding on the saw plate and ensure that your saw has full range of motion at the 45.

If the wood is blocking the saw from moving down completely, adjust it to the side as needed.

Then put the molding on the saw, upside down and at a 45 degree angle to the back.

It will be cut at a 45 bevel and 45 miter.

If your saw has a laser, great! Use it to ensure it’s in the right place. You want it to hit the bottom-most section of the molding exactly at your mark.

The molding should really be as exact as possible (no pressure!)

Make your first cut at one end of your molding, then swivel your saw the other direction at a 45, adjust your backing support wood as needed so your saw has full range of motion.

Then you’ll need to mark pieces for the sides. You’ll only need one mitered edge here (the side against your wall or bookshelf does not need a mitered edge.)

Measure from the corner of your box to the end of your mantle on the side. Make a mitered cut on one side and then measure out and mark the distance at the bottom of the molding.

You can either do just a regular cut for the side by the wall/bookshelf or (like we did) you can angle it slightly to allow more room for the wires to come out a little easier.

Attach molding.

You’ll need your buddy again to help with this step.

You’re going to attach the molding so that the bottom corners are perfectly aligned with the corner of the supporting box.

Clamp it in place.

Make sure it’s in the right spot before nailing in!

You can use finishing nails and a hammer for this, but I recommend using a brad nailer.

We didn’t have one either.

We borrowed my father-in-law’s (and by that I mean he came over and did it for us). You could also rent one for the day from your local hardware store.

Nail in the crown molding every 6 inches or so. Make sure it’s really on there.

Then you’re going to do the same process for the side pieces, ensuring the corners are perfectly aligned, clamping and nailing it in.

Once the molding is attached, your mantle will start to actually look like a mantle.

Very exciting!

Add panel molding.

At this point I also decided to add a little extra molding on the lower support box to amp up the aesthetic.

I picked up some 1-1/4″ panel molding for just a few bucks each. They came in 8′ sections, so I bought two.

The nice thing about this was the back was flat, so it didn’t need those fancy miter cuts. Our circular saw worked just fine for these.

The corners do need a 45 degree angle. The side adjacent to your wall or bookcase can be a regular 90 degree cut.

Since my mantel is longer than 8′, I also had to do a scarf joint to attach two of the pieces together seamlessly.

To do this, you’re just going to cut your joint at a 45 in the same direction so they fit together without sticking out like a sore thumb.

Like our TV? 😂 This is how we figured out it’s placement.

Use your brad nailer (or hammer and nails) to attach the molding to the lowest part of the mantle (or whereever you like it!).

Prepare your top mantel shelf.

The very top mantel shelf functions as a door to access the wires that will sit beneath.

Cut another 1×8 two inches longer than your first mantel shelf (to give you an extra inch on each side).

Then cut a 1×2 to the same length as your first mantel shelf, and then cut it in half (two pieces of wood, one for either side of the 2″ space in the center).

Remember, there will be an open space of 2″ in the middle of the mantel for the wires to come down.

(I know I’ve mentioned this 2″ space too many times, but it’s important. It also won’t be the last time 😆)

The three cut pieces will attach together with a piano hinge.

Cut side pieces.

If you don’t have any depth to your fireplace, skip this step.

Otherwise, you’ll need to cut side pieces to match the height and depth of the top shelf.

Measure the amount of space the top mantel shelf will hang over from the fireplace, and measure the space from the corner of the fireplace to the wall.

Cut two pieces of wood this size.

Ours was 3-3/4″ x 5-1/4″ space, so I cut a 1×4 to 5-1/4″.

Prepare for paint.

Make sure to give your mantel a good look and cover any imperfections first.

We made a lot of nail holes in this thing. Sink them if needed, fill all of them (that are visible) with wood putty and once it’s dry, sand it down.

This will give you a flat surface for painting and will ensure you’re not staring at nail holes for the next 50 years.

Also take your sand paper and go over the entire mantel to ensure there aren’t any rough spots. You want a nice smooth surface for the paint to stick to.

Wipe away any dust left behind.

Be sure to protect any other nearby surfaces with drop cloths and painter’s tape!

We also took this time while the room was torn apart to mount the TV. Check out how nicely those wires disappear 😉

Paint.

Stir up your paint, put some in a paint bucket and use a roller and/or brush to paint the mantel, making sure to get in every crevice.

I recommend painting (or staining) the top pieces (the 1×2’s and 1×8) before attaching them. This way you won’t get paint all over the hinges (if you paint anything like I do).

Also be sure to paint the top, side pieces that you just cut for your depth (if applicable).

You may have to go back and do some touch up paint for the nail holes after you attach the top mantel, but the bulk of the painting can be compelted now.

Attach hinges.

Once everything’s painted and dry, attach your hinges.

The flat side (with the screws) will be on the bottom and the actual hinge will be showing when the shelf is attached.

We purchased two sets of hinges, one for each side.

Don’t put a hinge in the middle of the mantel. There will not be anything for it to attach to as there will (again) be a 2″ space in the center of your mantel. You want one on each side.

Screw the hinges to your shelf first (the 1×8). They will typically come with screws. Use these if you’re able to.

For each individual hinge, I recommend you start screwing them in at both ends first and then working your way inward.

What commonly happens if you start at one end, is as you move along screwing the hinge to your wood, the hinge pulls closer to the wood. This changes the angle of the board and can make opening and closing difficult or lopsided.

Securing the outside ends first will help to ensure that they don’t move as you continue screwing them in.

(I’ve made all the mistakes so you don’t have to)

Once they’re attached to the shelf on both sides, you have to attach the other end of the hinges to your 1×2’s.

Align the 1×2’s with the end of the mantle on both sides and screw the hinges into place the same way, working from the outer screws to the inner.

For the last time:

***Make sure to leave the 2” in the center for your wires to go through! ***

Attach the top mantel shelf.

Now that your hinges are in place it’s time to attach the entire top section (the 1×6 and 1×2 joined by hinges) to the top of your mantel.

Align the 1×2 at the back of the mantel, adjacent to the fireplace.

You’re going to take your driver and make pilot holes, then screw the 1×2 into the lower support. Make several holes like this, every foot or so to ensure it is very secure.

The shelf will be free to open and close, so do not screw this side down!

Touch ups.

Pat yourself on the back! The building of the mantel is now complete.

Give your mantel one more glance for any nail holes that may need to be filled, sanded and painted, and do any other finishing touches that may be necessary.

We added a wire protector around the TV cords to make sure they are arranged neatly. The one from the TV to the mantel was spray painted gray to match the cement mortar.

You guys, don’t put this final step off until “later” that never comes. “Oh, I’ll just call it good for now and come back at some point and finish it.” If you’re anything like me, this won’t happen. You’ll move on to your next project and it will. not. happen. Just do it now!

Decorate.

WOOHOO! The very best part!!!!

You are amazing for making it this far. And you now have a gorgeous and custom centerpiece for your room that HIDES THOSE UGLY WIRES!!

Now let your creativity run wild and make it your own. I have some DIY’s, personal touches, family heirlooms, plants and candles on ours. Stay tuned for a DIY update on the living room decor soon!