How to Trim a Cased Opening and Half Wall for a Polished Look

The wall is down (more here). Drywall is up (more here). Now it’s time for trim.

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I actually enjoy doing trim. It demands focus and attention to detail, but it’s rewarding to see rough edges transformed into crisp white borders. Before getting to the trim, I had to handle the half-wall ledge and the door jambs.

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Our neighbors recently completed a similar opening and finished their half-walls with a wood platform top and trim beneath. We liked how finished and balanced it looked, and how handy it is for setting out small dishes or pre-poured drinks when entertaining. We picked up an eight-inch-wide, four-foot-long plank of pine to use for the ledge.

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Obviously the piece needed a bit of fitting. We trimmed one end and notched the other so the ledge would have an even overhang on both sides once the interior trim was added. We measured and marked twice to avoid mistakes…

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…then I took the plank outside and made the cuts—using a jigsaw for the notch and a miter saw for a straight end.

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I sanded the edges to soften the corners—no one wants a sharp ledge to bump into as they move through the opening.

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Fit-wise we got lucky: perfect on the first try. It looks long in some photos because the side trim hadn’t been installed yet; once the trim is added the ledge will have a slight, finished overhang like many of the windows in our house.

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With a couple of nails on each end, the ledge was secured into the frame. We’ll prime and paint it white to match the trim. Next came installing the door jamb on top of it.

Our opening matched a standard jamb width of 4 5/8″, so I used a pre-packaged door jamb kit from the store. The kit was intended for a standard three-foot opening, so I bought an additional side piece to extend the top jamb.

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The jamb covers the drywall and paneling edges so the finished trim looks seamless and you can’t see the raw framing from the side. The instructions suggested assembling the jamb and leaning it into the opening as one piece, but given our slightly different sizing we hung each piece separately. I cut and installed the short side first, then held it in place while nailing it with finishing nails.

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Next we slid in the short section of the top jamb and nailed it. It was starting to look like a doorway — the trim would finish the job.

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We had to join two pieces for the top jamb because we couldn’t find a single 92″ length. Once caulked and painted, the seam will be nearly invisible. I sank every finishing nail with a nail punch for a ding-free finish.

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With the top and sides in place, the jamb was complete. With the ledge and jamb finished, it was time to trim the opening.

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I won’t go into every step of trim installation here (we covered that before when re-trimming a bathroom). It involved measuring, miter-cutting, and carefully nailing each piece, then sinking the nail heads with a nail punch to avoid dings. We applied trim around all three sides of the opening on both the kitchen and dining room sides.

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We also added a slightly smaller piece of trim under the ledge to give it more presence because we liked the look from our neighbors’ home and it echoes the treatment of several windows in our house.

  • We liked how our neighbors treated their half-walls.
  • The dining room’s picture window and many other windows have a similar grounded ledge look.

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We also reinstalled baseboard removed during demo. Much of it was reusable, so we didn’t need to buy new pieces. Paint got scuffed in spots during removal and rehanging, but once everything is caulked and repainted it should be seamless.

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Some baseboard and quarter round may need to come up again when we do the floor, so we left certain sections unfinished. We completed most areas so the space looks as polished as possible during this construction phase, which will continue for a few months.

Here’s the room from both sides with the finished trim — it already reads much more like a proper doorway. We’ll paint the wood ledge white to better integrate it with the trim.

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To make the spaces feel more like a kitchen and dining room, we moved furniture back in. The kitchen chairs are temporary—eventual counter-height stools will be lighter and less wood-heavy. Excuse the temporary clutter; the room will feel calmer once those pieces are swapped out.

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There are still missing counters, unfinished walls and trim, and cabinets that need painting. Lighting, flooring, backsplash and other updates remain on the to-do list.

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We also found a final cabinet for the peninsula at the ReStore. The staff gave it to us after it had been left outside by the donor and couldn’t be sold. We aired it out, inspected it, and it checked out—no water damage or mold—and it’s a close match to our existing doors and drawers.

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The tape lines in a photo mark where the peninsula will end and where the 12″ counter overhang will stop, helping us visualize the final layout.

Even amid the chaos, the new opening is a game-changer. It brings more daylight into the kitchen and improves sightlines. Once the cabinets are painted and new white counters are installed, the room will feel even brighter, grounded by mocha cork floors.

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With the table back and curtains rehung, the opening aligns nicely with the dining room’s big picture window.

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From the other direction you can now enjoy the fireplace from the dining room.

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Through the dining room into the office, things are still staged temporarily — chandelier, dishwasher installation, and a buffet with art and a rug will help anchor the space.

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One of the nicest surprises is the peekaboo view into the hallway from the office, framed by the sunny kitchen beyond.

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We didn’t capture Burger sprinting through the new doorway—he was a blur—but Clara quickly took to the new route and seems to think it’s always been there.

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Here are a few photos from when we first moved in eleven months ago for comparison. It’s amazing how much has changed in less than a year.

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What a difference eleven months can make. There’s still more to do, but progress is steady and satisfying.

Cost-wise, finishing the entire opening ourselves was about $90. That covers drywall work, the door jambs and ledge, and trim on both sides. Hiring a contractor would have cost roughly $250, so doing it ourselves saved about $160.

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What did you do this weekend? Any jamb, ledge, or trim projects on your list? We spent plenty of time admiring the new doorway—and it feels great to see that little bit of finish make a big difference.