What a cornice window treatment can do for you

A cornice is the easiest way to give your room something 'extra'. These treatments are also known as valance boxes, cornice boxes, pelmets, or just plain cornices.

Which type of cornice to use?

There are many ways of making a cornice, but the most effective is to upholster the fabric onto a support. The support can be either buckram, which is a stiffened fabric, or wood such as hardboard. (Because buckram isn't as rigid as hardboard, cornices made using it are often classed as valances - incorrectly, in my opinion!)

shaped cornice box

This illustration shows a shaped cornice box. Using one cornice across both windows makes for a single window treatment.

Buckram is easier to cut out and attach to the mounting board. It gives reasonable results, but my preference is for an upholstered hardboard cornice. Buckram tends to warp, and looks lightweight. It's ok for smaller treatments, but for larger windows you can't beat a hardboard cornice.

I've always used hardboard even on small windows. When clients have questioned my advice, I've suggested that I install the hardboard version, and if they don't like it I'll replace it with buckram.

Guess what? No one has every asked me to change a hardboard cornice.

What are the advantages of cornices?

The advantages are both practical and visual.

  • Cornices hide the drapery hardware, such as track and brackets.
  • They show off both plain and patterned fabrics.
  • You don't need a lot of fabric to cover them because normally the fabric is applied flat. (You can gather the fabric for a special effect if you want.)
  • The fabric can be padded or quilted for extra effect.
  • They use up the 'dead space' above the window.
  • You can alter the apparent size of the window by extending the cornice up or sideways.
  • The lower edge can be cut to almost any shape you like.
  • They can be enhance by the use of rope, trim, tassel fringe, borders and many other accessories. These accessories can emphasize contrasting colors.

Here are some more things you can do with cornice boxes.

What shapes can you use?

cornice inset into window recess

One practical use for cornices is to hide unattractive window frames and tracks. This cornice inset into the recess does just that.

Just about anything you can imagine. But there are certain shapes which over the years have become favorites.

You'll find some examples of shape and other information on the designs page.

What do you need to make them?

Hardboard (or buckram if you prefer), interlining, lining, fabric (usually the same as the drapes), and any accessories you want to add. Oh, and the usual bits and pieces - needles, thread and fabric adhesive.

Making a cornice using buckram is the easiest, as you can cut the buckram with scissors.

If you're going to use hardboard or plywood, then a power jigsaw is very useful. And preferably somewhere else other than your workroom to do the cutting. The dust goes everywhere!

That's it!

The actual making just needs your time and application.

How are they supported?

The best method is using a mounting board. It will be secure enough to support the weight of the cornice and the drapes.


Cornice window treatments are much easier to make than most people imagine.

You can transform a good set of drapes into a superb treatment by the simple addition of a well designed and constructed cornice

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