DIY Trims: How to make a cased opening

If you had to define a cased opening in construction terms, you could call it a simple opening between rooms within the structure of the home. The term cased opening normally refers to an opening without a door, window, or other barriers that connects rooms or areas.

Common examples of cased openings in homes can be seen in arched doorways between the living room and dining room, or from a foyer into the family room. 

The casing around the door is usually made of wood. This wood trim usually matches all the other trim and crown moldings in the room. Common styles include mitered casings, butted casings, rippled casings, contemporary casings, and colonial casings. 

The national average cost of getting cased openings installed is between $629 to $980, or between $5.03 and 7.84 a linear foot. 

However, making a cased opening involves simple carpentry, and can be worked on as an engaging DIY project. This would allow you to save more than 50% of what it would cost to hire professionals. The cost per linear foot for only materials is around $0.94, with a range between $0.75 and $1.13.  Add around $27 for job supplies and between $64 and $86 to rent or buy equipment. 

Here are step-by-step instructions to show you how you can make a cased opening from scratch.

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Tools needed

1. Liquid nails
2. Brad nails
3. Brad nail guns
4. 1×4 MDF or pine boards
5. Corner trim
6. Tape measure
7. Caulk
8. Paint
9. Primer
10. Miter saw
11. Pencil
12. Wood filler

The process

1. Measure the opening so you can gauge approximately how many boards you will need to make the opening trim. While purchasing the boards, be sure to buy boards that are longer than the measurements you took. It always serves us best to leave room for mistakes.
2. Next, it is time for you to measure and cut the boards. Just to make sure you don’t make mistakes, measure each part twice before you start cutting.

While cutting the vertical pieces, remember to add a ¼ inch extra at the end of each board. The reason for this is because you will need to offset all your 1×4 boards by a ¼ of an inch away from your opening. This will give the opening a more professional and classy finish.

1. It is now time to begin nailing the boards to the wall. Use the pencil and tape measure to mark ¼ inches away from the opening in multiple places. Then, line up the boards alongside the marks. Then, apply liquid nails to the back of the boards and nail them in place.
2. The next step is to add the horizontal piece of the board on top of the opening. Measure from the end of one vertical board to the end of the board on the other side of the opening. This will give you the measurement for you to cut the horizontal board.

Once you’re done cutting the board, place it on top of the vertical boards, apply liquid nails, and nail it in place.

Finally, add corner molding to each side of the boards and miter the edges

Casing designs

The above process describes how you can install a very basic casing or trim for an opening in your home. However, there are many different types of casings that you could choose from. Let’s try and understand a few of the more popular casing designs.

Mitered casings

Mitered casings are what we have described above. They have three major parts, namely, the two vertical sides and the header casing. All these parts are connected together using mitered or angled joints.

While our description is of how you can make a basic mitered casing, a lot of homes also feature them with wider and more elaborate designs, often containing intricate designs.

For example, colonial-style casings are basically mitered casings with raised edges. Another popular version of mitered casings is to create a ripple effect by using multiple layers of mitered casings in different sizes to create an attractive but complex design, often seen in Victorian homes.

Butted casings

Butted casings are ideal for homes with high ceilings. They are similar to mitered casings in that they use three parts, but differ in that the header casing used in butted casings are wider and more ornate in design. This automatically draws the eyes upwards.

A common embellishment used in both mitered and butted casings is the use of rosettes, commonly known as decorative blocks, on the top corners.

Pro Tips

1. Make sure the design you choose for your casings complements the existing theme of your home, be it with base moldings, crown moldings, or window casings.
2. Your home’s architecture ought to also help decide the design of the casings. For example, ranch homes are informal in architecture, using simple lines. Victorian homes, on the other hand, are all about grandeur, high ceilings, and ornate crown moldings. This ought to reflect on the trim you choose.

Written by Narayan Shrouthy. December 28, 2021

Narayan is a content writer for Kukun. With experience in both content writing and editing, Narayan mixes his writing and love for reading with his passion for music. As an active musician, He aims to be a key player in Kukun's content experience.

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josh.124589@gmail.com(@josh-124589gmail-com)

Cased opening? You mean dust keeper