Elegant shower archway with green walls featuring white curved trim. The shower interior showcases glossy white marble-style tiles with a recessed shelf and a modern gold rain showerhead, highlighted by recessed lighting above.

DIY Curved Molding Around an Arch

Creating and installing curved molding might sound intimidating, but with PVC trim and a little patience, it’s completely doable. When I faced an empty space above the arch in my guest bathroom, it was the perfect opportunity to try out this technique. Let me walk you through exactly how I made it happen. Grab your heat gun, and let’s elevate your space with custom curved molding!

Elegant shower archway with green walls featuring white curved trim. The shower interior showcases glossy white marble-style tiles with a recessed shelf and a modern gold rain showerhead, highlighted by recessed lighting above.

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How I Installed a Beautiful Tile Tub Surround (And You Can Too!)
Upgrading Our Guest Bath with DIY Picture Frame Molding
How To Build an Arched Bathtub Alcove
How To Build a Brass Rail Shelf (high-end dupe)

What You’ll Need

Step 1: Prepping the Space

During my guest bathroom remodel, I built a stunning arched shower alcove that turned out even better than I imagined—it instantly elevated the entire space. When it came time to add box trim to the bathroom walls, I hit a creative roadblock: what should I do with the space above the arch? The solution? DIY curved molding.

Before tackling the curved molding, I first installed crown molding and box trim around the rest of the bathroom. This gave me a clear idea of how much space I had to work with above the alcove. With a vision in mind, I got started.

DIY bathroom renovation in progress with a person measuring a green wall for precise trim placement. The archway leads to a tiled shower area with white marble-like tiles and a luxurious gold showerhead.

After taking careful measurements of the arch, I cut out the straight-edged trim details and attached them to the wall using my brad nailer—easy enough. But the real challenge was figuring out the curved section at the bottom.

Completed bathroom renovation showcasing an arched shower entrance framed by decorative white trim. The green wall is accented by crisp, white molding, complementing the marble-tiled shower area with a sleek gold showerhead and handheld fixture.

Step 2: Shaping the Curved Molding

If you’re working in a bathroom, PVC trim is a game-changer. Not only is it waterproof and resistant to swelling, but it’s also highly flexible when heated. This makes it ideal for creating custom curved molding.

I started by cutting a piece of PVC trim slightly longer than I needed. Then, using one brad nail, I temporarily attached it to the wall at the center of the arch. With a heat gun, I carefully warmed the PVC trim, bending it gently to follow the curve of the arch.

Once I was satisfied with the shape, I marked where the ends needed to be cut for a perfect fit.

Step 3: Cutting the Angles

Lower Corner

After removing the curved trim from the wall, I used my miter saw to cut the lower corners. By marking where the pieces overlapped and splitting the difference, I achieved a clean, pointed angle that looked seamless.

Upper Corner

The top corners required a slightly different approach. Instead of a pointed edge, I wanted a flat, finished look.

To achieve that look, I marked where the trim overlapped, split the difference, and trimmed off the extra.

With all the pieces cut, I reattached the molding to the wall with my brad nailer and fine-tuned the fit.

View of a beautifully completed green archway with white curved trim details, complemented by crown molding and glossy marble-patterned tiles in the adjacent room. A clean and elegant DIY transformation.

Then I used my multi-tool to cut an angled notch and filled it with a small triangular piece of PVC trim. Voila!!! A little extra effort, but the result was perfection.

DIYer attaching a piece of trim to the upper curve of a green archway using a nail gun. The project showcases careful alignment and a mix of textures from tile, paint, and molding.

Finished Curved Molding

Once the curved molding was securely in place, it was time to finish the job. I caulked along the edges to create a smooth transition, and then filled the seams and nail holes with spackle (yes, spackle works great here!). Then I primed and painted everything for a cohesive, polished look.

Elegant shower archway with green walls featuring white curved trim. The shower interior showcases glossy white marble-style tiles with a recessed shelf and a modern gold rain showerhead, highlighted by recessed lighting above.

Adding curved molding to the space above the arch tied the entire bathroom design together. While I could’ve left the area blank, the custom trim brought an extra level of detail and sophistication that perfectly complemented the box trim on the walls.

So, if you’re looking to elevate your space, don’t be afraid to try your hand at creating curved molding. It’s easier than you think and delivers big design impact!

Would you like to see the full bathroom reveal? Click this link for all the details in one blog post.

A modern farmhouse bathroom with sage green walls featuring paneled molding, a dark wood vanity with brass hardware, a white countertop, and gold fixtures. The room is styled with a vintage gold-framed landscape painting, wooden wall hooks, and a small floating wooden shelf holding decorative jars and greenery.
What is curved molding?

Curved molding is a type of decorative trim designed to follow rounded or arched architectural features, such as doorways, windows, or alcoves. It adds a polished, custom look to any space.

Why is PVC trim recommended for curved molding?

PVC trim is lightweight, flexible, and waterproof, making it ideal for bathrooms or areas with moisture. It can also be shaped with heat, which is crucial for creating smooth curves.

What tools do I need to create curved molding?

The tools you’ll need include:
A heat gun for shaping the PVC trim
A miter saw for precise cuts
A brad nailer for attaching the trim to the wall
Caulk and spackle for finishing touches

Does curved molding increase a home’s value?

Yes, custom details like curved molding can elevate a home’s aesthetic appeal, making it look more high-end and cohesive. This can potentially boost a home’s value by enhancing its overall design.

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