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Exterior Barn Doors, Hardware And How to Build One

While barn doors started outside (of course) they rapidly moved indoors over the last decade and have become a popular alternative to standard passage doors.

But once a trend takes hold, the tendency is for it to grow. So, of course, barn doors returned outdoors to structures like sheds and garages as aesthetic and functional ways to improve the look of buildings.

As a long-time woodworker, learn how I made both the barn door and installed it with a galvanized steel barn door hardware kit.

Where to Start: Size of Door and Rails

First, and I didn’t expect this, one of the most confusing steps with any barn door project is choosing the size of the door and rail.

While a traditional passage door fits a standard opening, a barn door covers an opening and is generally 3-4″ or more wider than the opening.

Which requires a bit of thought on sizing the door to the trim and choosing the right rail size. For this project, I was covering a 30″ exterior door and chose a 36″ barn door (and a 72″ head rail). Wider was better.

Materials Required

For both building the door and installing the barn door I used the following:

Door Materials

  • 2×8″ rough cedar
  • 1×4″ rough cedar
  • Titebond III wood glue (waterproof)

Exterior Barn Door Hardware

Building the Door Panels

While daunting to some, making a barn door slab is really nothing different than making a cabinet door. 

Except, as you can guess, everything is bigger and heavier.

Getting started, the primary steps in starting the door panels are:

  • Finalize door width and height
  • Decide on a panel configuration (2+ panels are a minimum). As you’ll see my door is a Shaker-style 3 panel.
  • Rough size your panels by drawing out the door on paper. But if you’re not comfortable with that, a sheet of plywood will give you life-like dimensions.
  • Oversize the panels a few inches in length and width

Once you have rough panel sizes, it’s time to start cutting.

Make Wood Strips for the Door Panels

Gluing Cedar Panels

After building thousands of cabinet doors and hundreds of passage doors I’ve learned a few tricks to making panels.

First, never use a strip of wood wider than 3.5″. Because wood will adapt to the humidity of its environment (hopefully at an even rate), it will swell. And narrower boards, as they take on humidity, have less risk of warping or splitting as their movement is less.

So, do some calculations on how many boards you’ll need, then start with your LONGEST panels first and make your cuts. After you have all of your strips, prepare them for gluing with a jointer to make the edges perfectly flat over the length of the board.

Choose Waterproof Glue

Exterior Wood Glue

An exterior barn door will obviously be exposed to the elements.

Which means both the wood and the glue used to assemble it must be made for the elements. 

While my standard glue is Titebond II, for this door project I picked up a bottle of Titebond III that is waterproof and made for exterior projects.

Clamping the Door Panels

Glue Cedar Barn Door Panels

With both your panels and glue at the ready, it’s time to assemble the door panels. While my shop has dozens of pipe clamps (pictured) that are cheap and easy to use, you can use a variety of other wood clamps.

Steps to glue the panels:

  • Layout the panel on the clamps
  • Flip all but the first strip on edge (facing you)
  • Apply a consistent bead of glue to the edges of all the strips
  • Starting with the glued strip closest to you, flip it down and gently rub it against the first strip to even the glue
  • Repeat for all strips.

When clamping, I’ll use a clamp roughly every 10-inches and alternate top and bottom for even  pressure. 

And, when tightening the clamps, remember the goal isn’t to squeeze the glue out of the joint. Instead, apply even pressure on all clamps and a strong hand tight is all you’ll need.

Note: You do not need pocket hole screws, biscuits or other joinery assists to the glue. Once a proper wood glue dries the panel will typically break anywhere BUT the glue joint. It’s simply a waste to use pocket hole screws to “assist” a glue joint.

Sand the Door Panels

Course Sanding Door Panel

You might be asking why sanding the door panels is next, right?

Well, put simply, its easier to machine the door rails and stiles to the finish panel thickness than the other way around.

My shop has a drum sander, dust collector and can sand panels in 20 minutes using grit as low as 24-grit. But, belt sanders or an aggressive orbital sander like Festool’s can be used.

Sanding Door Panels

Machining the Door Rails and Stiles

Rough Cedar Barn Door Lumber

Once the panels are sanded and their thickness can be used to set the door frame its time to build the door.

Before we start, though, there are two terms used in door making to know:

Stiles are the vertical edges of the door and are simply remembered as “stiles stand”.

Rails are the horizontal connectors and will have both edges grooved to accept panels and ends cut to match the stiles panel relief.

Dado the Rails and Stiles

Exterior Cedar Door Stiles Shaker Construction

For most doors and DIY projects the simplest way to construct the frame is with a simple shaker-style joint. Using a stack dado set on a table saw, setup a test block of wood and make a perfectly centered groove that matches the panel thickness.

Noting, as you make this groove, you want just enough play in the groove that the panel will easily slide in without force. But, not too loose that the panel will rattle.

Cut Rail Ends

Exterior Cedar Door Rail

After the panel grooves are cut, using a table saw sled (or router table) make a tenon out of the ends of the rails that will fit the panel groove.

A few tricks for this step:

  • Start shallow with your first cut until you remove just enough wood that you expose the tenon (as shown).
  • Make sure your jig is square, as the shoulder of this cut will determine your doors overall square later.
  • Avoid splinters and tear-out by using a backer board
  • Fit, re-fit and re-fit again to make sure you have a snug fit between the rail end and the stiles.

Dry Fit the Door Rails and Stiles

Shaker Barn Door Construction Side Rail

Once you have the rails and stiles shaped and cut to length its time to dry fit the door. When making cabinet doors most woodworkers will skip this step as the measurements are standard.

But, for unique doors like a barn door slab, its best to do this step, measure and THEN cut the door panels to size.

Cut the Door Panels to Size

Leaving Expansion Room in Door Panel

When it comes to wood the first assumption is it will always take on humidity and swell.

And the amount of swelling can be correlated to the width of the wood. 

Which means you will want to leave a generous amount of room to grow for your exterior panels (1/4″ is typical). 

Dry Fit the Door Before Gluing

Dry Fitting Cedar Panels

Before applying glue, it is best to dry fit the panels and door completely to make sure everything will fit. Because, after you apply the glue, you’ll have only 15 minutes to work with the door before it starts to set.

While hard to see in the picture, note the pencil marks on the rail ends that match up to marks on the door stiles to indicate where the centers will line up during gluing.

Gluing the Barn Door

Gluing Door Rail Ends

There is nothing a woodworker likes less than wood glue on a finished surface. And, that is closely followed by having to fix a door panel that split because it was glued to the door rails and stiles.

The solution? 

When gluing your door remember the door rail (and stile, if you have vertical dividers) need enough glue to hold a joint, but no excess glue that creeps into the door panel.

Note the picture above where the glue is intentionally applied to the center of the rail ends. Some could argue for more glue, but I have yet to have a door fail on a glue joint.

Assemble and Clamp

Pipe Clamps to Clamp Door Frame

While assembling the door I like to have it balance on edge. But for clamping, I’ll lay it flat and use two bar clamps (one to a side) to apply even pressure on the joints.

During clamping, keep an eye out for any glue that is compressed onto the edges of the rails and stiles.

Also, depending on the wood material and bar clamp, use blocks to avoid creating indentations on the edge of the door.

As seen below, with proper milling and gluing you should very little squeeze out of glue and a door frame that will require minimal sanding.

Glue Cedar Barn Door Frame

Sanding the Barn Door

Drum Sanding Barn Door

For glue to properly dry and be handled I left the door in clamps overnight and sanded the next day.

And, of course, used my drum sander with 24-grit to grind the door to a finished, smooth surface. While your tools may vary, I like to use a progression of sandpaper grits from 24, 60, 120, 180 to 220 to remove material first and then the sandpaper marks.

Course Sanding Door Frame

In the image above, note the rough cedar grain is gone but is replaced with marks left by 24-grit sandpaper.

Finishing The Door And Installing Hardware

Drilling Barn Hardware Bolts

After sanding the door, using a quarter-round to soften the edges and applying a few coats of deck stain (Cabot’s is my preferred) its time to install the barn door hardware.

The first step, as shown above, is to follow the instructions provided with the hardware. For my door, the door required eight holes to allow for carriage bolts and the hanging bracket.

TIP: Use a backing board while drilling to reduce tear-out when the drill bit comes through the back of the door.

Trim the Bolt Heads

Flush Trimming Barn Door Hardware Bolts

The instructions didn’t say to do this, but you don’t have an option: since a barn door slides it requires clearance. And the bolts supplied where long enough to accommodate a thicker door. 

But, for my 1-3/4 thick door I needed to cut the excess bolt length off. And, like most projects, there are a few solutions. Using one of the handiest tools I didn’t know I needed until I bought it, my oscillating tool made quick work of the bolts.

Installing the Barn Door Rail

Leveling Barn Door Hardware

For this shed project I had pre-planned a header knowing a barn door would come later. And, since planning is everything in woodworking, I had purchased the rail first and made sure everything would fit and look professional when done.

For this step, the brackets that will hold the galvanized tube needed to be installed first. Since I had pre-planned the door height by temporarily setting these first, I knew where to install them for height. For width, I installed them about 12″ in to give support to the rail in the center. 

Install the Barn Door Header Rail

Galvanized Barn Door Hardware

This was the easiest step in the process as the brackets allowed for the rail to slide in from either direction. 

As pictured below, the galvanized look was an option but we opted for an exterior-grade black paint to reduce the galvanized shine. 

Painted Barn Door Hardware For Exterior Door

Install Barn Door Rail Ends

Installing Barn Door End Stop

To keep the door from sliding off the ends, the last few steps will be to install stops, end caps and any other items included with your hardware kit.

As shown below, and not in the instructions, I had to add a locking screw to keep the door rail in place when the door was installed.

Installing Locking Screw Barn Door Hardware

Installing and Leveling

Barn Door Hardware Wheels

Of course, sitting inside the header rail must be the wheels that will make the door go back and forth. And, for this rail kit a standard pocket-door-like set of eight wheels was provided.

After attaching these to the door and sliding these into the rail (before the last end cap, of course), a little adjustment might be needed to level the door.

All that will be left is deciding on a handle and adding a door catch (optional, but recommended) to keep the door in place.

I didn’t add a bottom door rail guide, but might in the future.

Exterior Barn Door With Galvanized Hardware

Links and Ideas

While this project involved a standard sized barn door that concealed a standard garage-style door, there are a huge variety of applications and sizes.

Here are a few places I used in researching this project:

  • About the Author
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( Woodworker )

Eric has been a professional woodworker for over thirty years and has worked in small cabinet shops making everything from kitchen cabinets to hand-made furniture. Now working from a home woodworking shop Eric is sharing his passion for woodworking, tool advice and how-to knowledge from his Minnesota-based woodshop.

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Disclaimer: DIY projects can be dangerous, hire a professional (link to Home Advisor) if unsure.