How do you make wooden cornice boards for windows?

Cornice boards are decorative moldings that sit above windows to add visual interest and architectural detail. Making your own wooden cornice boards allows you to customize them to your exact window sizes and design aesthetic. While it requires some woodworking skills, the process is very doable as a DIY project.

What is a Cornice Board?

A cornice board sits on top of a window casing to conceal the curtain rod or blinds hardware. It consists of two main parts:

• The “bed molding” attaches directly to the wall and provides a foundation for the decorative overlay molding.
• The “crown molding” sits on top of the bed molding and features decorative ridges, curves and edges.

Cornice boards typically extend 4-6 inches outward from the window frame to create a visible overhang. They can be painted to match the wall color or finished in a contrasting tone.

Benefits of Installing Cornice Boards

There are several benefits to adding cornice boards above your windows:

• They give windows a finished, built-in look.
• They conceal unattractive curtain rods and blinds hardware.
• They allow you to layer window treatments elegantly.
• They add architectural interest and visual appeal.
• They can help make windows appear larger or wider.

Choosing Wood for Cornice Boards

Cornice boards are traditionally made from wood products. The most common options include:

• Pine: Pine is an inexpensive softwood that’s easy to cut and nail. It accepts stain and paint well. Pine cornice is a budget-friendly option.
• Poplar: Poplar is a versatile hardwood that’s easy to work with. It can be stained or painted. Poplar has a fine, consistent grain.
• Oak: For a durable hardwood option, oak cornice boards add timeless elegance. Red oak is most common. White oak works too.
• Maple: Hard maple cornice has a fine, smooth grain that looks great with clear finishes. It brings a light, airy aesthetic.
• Cellular PVC: For exterior use or wet areas, cellular PVC is a durable synthetic wood replacement that won’t rot.

The wood should be kiln dried with a moisture content of 10-15% to prevent warping. Select boards that are straight and free of imperfections.

Cornice Board Dimensions

Standard thickness for cornice boards ranges from 3/4 inch to 1 inch. Depth is based on the desired overhang, commonly 4 to 8 inches. Length should match your exact window width plus an extra 1-2 inches on each side.

Bed molding is usually 1×4 or 1×6 stock. Crown molding can be anywhere from 2 to 6 inches tall depending on the style. For DIY boards, simple, smaller moldings are easiest to work with.

Tools and Materials Needed

Making your own custom cornice boards requires just a few common tools and supplies:

• Miter saw
• Table saw, circular saw, or jigsaw
• Drill and drill bits
• Wood glue
• Finishing nails
• Wood putty
• Sandpaper
• Primer and paint or wood stain
• Wood boards for bed and crown molding

Cutting the Molding Pieces to Size

Start by measuring your windows carefully to determine the exact lengths needed for the bed and crown molding boards. Cut the boards slightly longer than the window width to allow for mistakes. Cut the crown molding board to the desired overhang depth.

Mitered joints are best for cleanly joining the molding corners at 45 degree angles. Cut the ends of each board at 45 degrees so the moldings seamlessly fit together.

Assembling and Installing the Cornice Frame

Lay the cut boards on a flat surface and assemble the mitered frame using wood glue and finishing nails. Nail through the crown molding into the bed molding to securely join them.

You can pre-finish your cornice board frames before installing for easier painting. Once assembled, attach the frames centered over each window using finishing nails. Make sure they are level and leave a border on all sides.

Filling Nail Holes and Applying Final Finish

Go back and fill any visible nail holes with wood putty. Allow to dry completely. Sand smooth. Finish as desired with primer and paint, or apply your choice of wood stain and sealer.

Installing Curtain Rods and Hardware

The cornice board frames support your curtain rods, cafe rods or other hanging hardware. Position the brackets to align with the interior framework. Screw them into place through the crown molding.

For a professional finish, cut notches in the back side of the crown to recess the hanging brackets. This conceals the hardware completely behind the cornice molding.

Decorative Touches

To enhance the custom look of your DIY cornice boards, consider adding extra details like:

• Corner molding blocks for an elegant transition between walls
• Rosettes at the corners or midpoint to accent the framework
• Fluted or shaped molding profiles for unique shadow lines
• Inlay bands within the crown molding for visual interest
• Cap trim atop the crown for a built-up, layered look
• Cove or quarter-round molding where the bed molding meets the wall

Cornice Board Ideas and Inspiration

Cornice boards are available in endless styles to match any design aesthetic. Consider your room’s architectural details when selecting a profile design. Here are some cornice board ideas to inspire you:

Formal Traditional Cornice

For a formal look, choose a built-up cornice with a deep crown molding, intricate curves and layered trim details. Fluted trim and rosettes add sophistication.

Rustic Farmhouse Cornice

A simple, chunky crown molding made from weathered barnwood creates rustic farmhouse style. Keep the lines clean for a pared-down look.

Modern Shaker Cornice

Focus on clean lines and minimal ornamentation. Straight, square-edged boards have a contemporary vibe. Paint in bold, modern hues.

Cottage Cornice Boards

Cottage-style cornices feature gently curved, notched or scalloped edges for whimsical charm. Soft pastel colors enhance the dreamy vibe.

Transitional Cornice

For transitional spaces, blend elements from traditional and contemporary styles. A streamlined crown molding with simple detailingbridges both worlds.

Coastal Cornice Board

Wide crown molding evokes breezy waterfront vibes. Crisp white paint keeps the coastal look light and airy.

Pro Tips for Perfect Cornices

Follow these professional tips and tricks to ensure your custom cornice boards look polished and flawless:

• Use a miter box guide to cut super-sharp joints at the perfect angle.
• Glue joints and use 2″ finishing nails. Nail through the crown into the bed molding for stability.
• Pre-drill holes to prevent splitting if nailing near board ends.
• Fill gaps with wood putty before painting for a seamless look.
• Sand between coats of paint for a smooth, professional finish.
• Size bed molding wide enough so curtain brackets are fully supported.
• Add corner blocks for a clean transition of inside corners.
• Prime boards before installation for easier painting.

Conclusion

With some basic woodworking skills and the right materials, you can create beautiful, customized cornice boards for your windows. Accentuate your home’s architecture while adding decorative flair. For a designer touch at a fraction of the cost, DIY cornice boards are a budget-friendly upgrade for your windows.