How Do You Install a Barndominium Window?

How Do You Install a Barndominium Window
How Do You Install a Barndominium Window

A barndominium is a type of metal building that combines the size and space of a barn with the features of a home. When building your dream barndominium, there will be a time when you need to cut into the metal siding and install windows. Make sure to do this correctly, or you could end up with a compromised structure. 

To install a barndominium window, begin by determining the placement of your windows, avoiding x-frames and support beams. Then, cut through the metal siding, creating a hole the size of the window. Next, install J-trims around the hole, then caulk and slide the window into place.

In the following article, we will examine these steps in greater detail. We’ll also address what types of windows you can install in a barndominium, and some tips for placing windows.

Deciding on Barndominium Window Placement

The first step to installing a barndominium window is to decide where the windows should go. There are many important things to consider when designing a building and planning window placement, structural integrity being one of them.

What Is Structural Integrity?

Structural integrity is the ability of a building or structure (like a bridge) to bear a load. There are people in the world that specialize in the structural integrity of large productions, like city bridges, highway tunnels, and production plants. These people are called structural engineers

While a structural engineer is not necessary to determine the load-bearing capacity of your new barndominium, a professional that is versed in this area is important. Hiring, or at least consulting with, an architect will help you determine the appropriate design for your home.

Architects determine the parts of the building that need to be there to make a solid structure, while also considering where windows should go for aesthetics and airflow. They can help you decide where to put windows that will look the best, and avoid interfering with things like support beams.

In a barndominium, you cannot place a window where there is a support beam, nor where there is an x-brace. An x-brace, or cross brace, is a type of reinforcement commonly used in steel structures. These braces can run along a wall or through the middle of a space to connect two pillars. The cross-action of the brace allows for a stronger structure and therefore increases the load-bearing ability of the building.

This is one of the reasons it’s important to discuss with a professional, or at least with the company drawing up the plan for your home. The x-brace is a large contributor to your home’s structural integrity, but it can usually be moved if you give the designer notice of where you want your windows in the planning stage. 

Indoor Lighting and Aesthetics

Once you’ve considered your home’s structural integrity, you can start planning window placement according to the desired lighting and looks. Depending on your property, you may want to frame a specific view with your windows. 

If you are lucky enough to have a beautiful view all around, follow this guide for window placement:

  • East-facing windows are ideal for kitchens and areas that you’d like the invigorating morning sun.
  • West-facing windows are perfect for romantic scenes, like sitting rooms and master bedrooms with balconies.
  • South-facing windows let in the most daylight, which some may find overpowering, but is perfect for stairways and growing indoor plants.
  • North-facing windows are a favorite for studies and nurseries, as they tend to let in calming light all day.

Outlining the Window

Once you’ve decided on window placement, you can begin the window installation. The first step in this procedure is to outline where the window will go on the interior of the metal siding.

Set up your laser level facing the wall where the window will be going. Shine the laser across the top horizontal part of the window’s future placement. Measure out the width of the window, and, using the long level as horizontal support, draw a line tracing the upper part of the window frame.

Measure and mark the lines for the sides and bottom of the window as well. Once completed, you should have a large rectangle or square the window’s size and shape on your wall. This outline is going to serve as the cutting diagram for the next step.

For an example of this, watch this video:

Cutting the Hole for the Window

The next step in the window installation is to cut the hole for the wall in the window. When using a metal cutting tool, like the Dewalt Angle Grinder, cut along the metal siding where you’ve traced the outline for the window. Be sure to use appropriate PPE (personal protective equipment) to guard against flying sparks and metal.

Cut along one line at a time, trying to keep as steady as possible. Any mistakes in this area and you may have an irreparable leak in your siding. Remove the piece of sheet siding and put it out of the way.

Cut and Install J-Trim

Installing J-trim is the next step in our window installation process. J-trim is a piece of bent metal that fits over the raw edges of steel in the walls. Not only does J-trim serve to buffer and protect against the sharp edges of metal, but it also creates a uniform look around the edges of the steel. It also protects the raw edges of steel from the elements, acting as a defense against corrosion.

J-trim is called such because of the J shape of the piece. The space in the J slides over the steel siding, and the little leg of the J sits on the exterior of the building, while the large side of the J sits on the interior.

You’ll need a piece of J-trim for each side of the window. Cut these four pieces of trim to 2″ (63.5 cm) longer than the necessary measurements for the window sides. We’ll need the extra length to cut overlapping pieces into the J-trim. This will allow rain that enters the top piece of J-trim to run off the sides of the trim and down the siding without damaging your barndominium.

To cut the necessary overlapping pieces for the trim, you need to know how to notch and miter corners. A good video on how to do that is here:

For the bottom piece of J-trim, you will cut in two 1″ (2.54 cm) notches on either side of the trim. You can then install this piece on the bottom of the window hole. As mentioned earlier, the piece should slide right over the steel siding. Make sure the longer edge of the J is facing the interior of the building.

Next, cut and install the top piece. This piece will have mitered corners on either side, so there are two 1″ (2.54 cm) flaps of metal that face downwards at each end. Caulk the inside of the J-trim to create a seal against the trim and the steel wall.

Lastly, cut and install the side pieces. Each of these pieces will have a tab at the bottom (a mitered corner) and a notch at the top that will create the necessary layering for the rain to run off. Caulk these pieces before installation as well.

It’s important to be generous with your caulking, as this is the main sealant to protect the interior of your barndominium from rain. If you’re worried about erring on the side of too little or too much caulking, always lean towards too much.

Install the Window

The next step is to install the window. If your J-trims were cut and installed properly, they should have created a nice frame for the window to slide into. To prepare for the window, you need to caulk the trim generously. 

Apply caulking to the inside flat edge of the J-trim all along the four sides. Add an extra bead of caulking in each corner. Also, apply caulking to the sides of the J-trim that faces the interior of the building. This is a crucial layer of sealant in defense of your house from the weather.

Next, slide your window into the framed hole. Press firmly against the frame of the window to make sure that the caulking bonds. The window should fit perfectly into the frame you’ve created; if it isn’t snug, you’ll have to remove the window and perform some corrective measures.

For a good example of the caulking process, take a look at the video below:

Reinforce the Window

The last step in installing a window in a barndominium is to reinforce the window against the siding. At this point in time, the window is simply sitting in the frame that you have made for it. You need to create braces around the window to ensure that it is held in place. 

You can use wooden 2x4s for this, or pieces of steel. Cut the pieces to fit flush with each other around the inner edge of the window.

Next, you’ll screw into the 2x4s from the exterior of the building. This part of the process is also much easier to complete with a second set of hands, so ask a partner or coworker to help you out. 

One person is going to stand in the interior of the building and place a 2×4, along the inside of the window. The wide edge should overlap the window’s interior frame. The other person will stand outside of the window and, using a screwdriver, drill through the steel wall and into the 2×4 or steel beam. This will pull the screw and the 2×4 tight, and hold the window in place.

Repeat this process for all four sides of the window, creating a secure hold between the window and the steel wall.

Insulate and Finish

Now, your window is fully installed. You can continue with the insulation and finishing of the interior walls of your barndominium.

Tools Needed for Barndominium Window Installation

There are a variety of tools necessary to complete this installation. It’s best to collect all of these tools first, so you don’t have to leave the project half-completed to fetch one of them.

  • Measuring tape
  • Laser level
  • Marker/pencil
  • Window
  • Long level or yardstick
  • Caulking gun and caulk
  • Angle grinder
  • Band saw
  • Screwdriver and screws

Personal Protective Equipment for Installing Barndo Windows

Be sure to use proper PPE (personal protective equipment) when performing this and all other construction tasks. There are a few key pieces of safety equipment you should invest in before taking on this project.

These 3M Safety Glasses will keep your eyes safe during this task. They are particularly important while you are cutting out the window’s shape from the siding to guard against any metal pieces that might be sent flying.

A thick pair of work gloves are also important, as they can save your hands from cuts from handling the sharp steel siding. These Ironclad General Utility Work Gloves include a synthetic leather palm to provide protection from heavy or rough objects.

Angle grinding through a steel wall is a very loud task. The sound of which can damage your eardrums unless you’re using proper PPE. These Professional Safety Earmuffs from Decibel Defense are the perfect accessory to keep your hearing safe.


Installing a barndominium window is a relatively easy task, as long as you know your tools and how to use them. Knowing how to notch and miter the corners of your J-trim will ensure that you install a window that lasts. Caulking is also important against waterproofing, and getting someone to help you hold and reinforce the window is key to a job well done.

Don’t forget to consult with a professional when deciding on where to place your windows. Also, be sure to let your designer know which side of the house you’d prefer to have the windows on so that they can move the integral components accordingly.