Is It Normal for Roller Shades to Leave Gaps on the Sides?
TLDR;
Yes, it is normal for
roller shades to leave gaps on the sides, especially with inside-mounted installations. These gaps, often ½ inch or more on each side, are necessary for smooth operation and clearance for the roller mechanism. If side light leaks are a concern, you can use outside mounts, side channels, or layering techniques to reduce or eliminate them. Understanding these gaps can also help when evaluating
roller shade durability, since proper clearance prevents unnecessary wear and extends the life of the shade.
Why Side Gaps in Roller Shades Are Normal
Roller shades often have visible space between the fabric edge and the window frame. This is not a defect but a design requirement.
- The roller mechanism and brackets need clearance to function without scraping
- Fabric width is narrower than the total shade width to allow smooth rolling
- Inside-mounted shades leave more noticeable light gaps than outside-mounted shades
Industry standards suggest about a ½ inch gap on each side for inside mounts.
How Inside Mounts Affect Side Gaps
Inside-mounted roller shades are installed within the window frame. While this creates a clean, minimal look, it also means:
- Shade fabric is reduced in width to fit between brackets
- Side gaps allow free movement of the fabric without binding
- Gaps are more obvious in bright daylight or when blackout shades are used
Average inside mount side gap: ½ to 1 inch per side.
How Outside Mounts Reduce Gaps
Outside mounts are attached to the wall or trim above the window. This method can greatly reduce or eliminate side gaps.
- Shade width can extend 2 to 3 inches beyond each side of the frame
- Light leakage is minimized because the fabric overlaps the wall surface
- Works well for bedrooms, media rooms, and offices where darkness is needed
Consequences of Side Gaps
Side gaps are normal, but they can create functional issues depending on the room use.
- Light leakage in bedrooms can disrupt sleep
- Glare on TV or computer screens in media rooms
- Reduced privacy in bathrooms or ground-level windows
These issues are more noticeable with blackout fabrics, which block light through the material but not around the edges.
Exact Measurement Standards
The gap size depends on the mounting style and manufacturer.
Typical inside mount roller shade measurements:
- Total shade width = window width minus 1 inch
- Fabric width = total shade width minus 1½ inches
- Resulting gap = about ½ inch per side
Outside mount recommendations:
- Shade width = window width plus 4 to 6 inches
- Full overlap prevents side light leaks
Differences by Shade Type
- Roller shades: largest gaps due to exposed mechanism
- Cellular shades: smaller gaps but still present
- Roman shades: minimal gaps but not ideal for total blackout
- Dual shades: same clearance needs as standard roller shades
Solutions to Minimize or Eliminate Side Gaps
Choosing the Right Mount
- Inside mount for a streamlined look but expect light gaps
- Outside mount with extra overlap for maximum coverage
Using Side Channels or Tracks
- U-shaped or L-shaped channels mounted along the sides of the window
- Block light completely and guide the fabric for a tighter seal
- Best for bedrooms, nurseries, and home theaters
Adding Light-Blocking Strips
- Adhesive L-strips mounted inside the window frame
- Narrow profile that blocks most side light without a full channel system
Layering Window Treatments
- Combine roller shades with curtains or drapery panels
- Drapes add blackout coverage and a decorative element
- Works for both inside and outside mounts
DIY Gap Solutions
- Magnetic strips to hold blackout fabric against the frame
- Foam or weatherstripping tape to block small leaks
- Velcro strips for removable blackout side panels
Shade Upgrades
- Choose roller shades with built-in side light blockers
- Consider cellular shades with side tracks for better sealing
Choosing the Best Fix for Your Situation
| Situation | Best Solution | Benefits |
|---|---|---|
| Bedroom, light-sensitive | Side channels + blackout fabric | Total darkness |
| Media room | Outside mount with overlap | Eliminates glare |
| Budget-conscious | Light-blocking strips | Affordable and easy |
| New installation | Outside mount with 2–3 inch overlap | Prevents gaps entirely |
Frequently Asked Questions
How much side gap is normal on roller shades?
½ to 1 inch per side for inside mounts.
Do blackout roller shades block all light?
No. They block light through the fabric but not around the sides unless side channels or overlaps are used.
Can I add side channels to existing shades?
Yes, many aftermarket kits are available and easy to install.
Are outside mounts better for blocking light?
Yes. They cover a larger area and reduce side gaps significantly.
Will layering curtains over roller shades block light completely?
Yes, especially when using blackout curtain panels that extend past the window frame.
Maximizing Light Control with All Window Decor
At All Window Decor, we measure and install roller shades with your specific needs in mind. Whether you prefer the sleek look of inside mounts or the blackout performance of outside mounts, we guide you toward the right choice.
Our team offers:
- Precise measuring for optimal fit
- Side channel installation for blackout results
- Layered
window treatment design for style and function
Contact All Window Decor to learn how to eliminate side gaps in your roller shades and get the best performance for your space.
