Common DIY Window Treatment Mistakes Designers See All the Time

Common DIY window treatments may seem straightforward, but designers consistently see the same mistakes that prevent a space from looking polished and functioning properly. Window treatments are both visual and architectural elements, and small errors can make an otherwise well-designed room feel unfinished.

Below are the three most common DIY window treatment mistakes, and why they matter.

DIY Window Treatment Mistakes

1. Incorrect Measurements

(The most costly DIY window treatment mistake)

Incorrect measurements are the leading cause of failed DIY window treatments. Measuring windows is more complex than it appears, especially when accounting for trim, depth, and mounting style.

Common measuring mistakes include:

• Measuring only the glass instead of the full window opening

• Overlooking depth requirements for inside-mounted shades

• Ignoring uneven walls or molding

Poor measurements often result in window treatments that don’t fit, operate improperly, or require complete replacement—making this the most expensive mistake to fix.

2. Improper Drapery Placement

(Too low, too narrow, or too short)

One of the easiest ways to spot a DIY installation is drapery that isn’t positioned correctly. Incorrect placement can make ceilings feel lower and windows appear smaller than they actually are.

Designers frequently see:

• Curtain rods mounted directly on the window frame

• Panels that don’t extend wide enough beyond the window

• Drapery that stops awkwardly above the floor

Proper drapery placement enhances proportion, improves light control, and creates a more elevated interior design result.

3. Choosing Style Over Function

(Ignoring light control and privacy)

Another common DIY window treatment mistake is prioritizing appearance without considering how the room is used. While a window treatment may look good during the day, it may fail to provide privacy, light control, or comfort when it matters most.

Designers often encounter:

• Sheer-only treatments in bedrooms or street-facing rooms

• No layering strategy for flexibility throughout the day

• Fabrics that don’t perform well in high-light or high-use spaces

Well-designed window treatments balance aesthetics with function, ensuring the space works just as well at night as it does during the day.

Final Thoughts

DIY window treatments often fall short not because of poor taste—but because of overlooked details. Designers approach window treatments holistically, considering measurements, placement, and function together.

Avoiding these three common mistakes can make the difference between a room that feels “almost finished” and one that feels truly complete.

When window treatments are done correctly, they don’t just cover a window—they elevate the entire space.