Even the best blackout window blinds can sometimes leave gaps on the sides, allowing unwanted light to sneak in. Whether you’re trying to sleep better, create a movie-theater vibe, or enjoy complete privacy, blocking light from blinds can make all the difference. This guide walks you through the most effective and practical solutions.

Why Side Light Leakage Happens

Before diving into solutions, it’s helpful to understand what causes light to seep in from the sides of your blinds.

Common Causes:

  • Standard blind sizing that doesn’t account for overlap
  • Improper installation or wall gaps
  • Window frames that don’t support flush mounting
  • Low-quality materials or fabric that doesn’t block light effectively

Even using premium blackout window blinds, side light leakage can still occur without the right setup.

Top Methods to Block Light from the Sides of Blinds

If you’re wondering how to block light from the side of blinds, here are the most popular and effective methods.

1. Use Light Blocker Side Channels

Side channels are one of the most professional ways to eliminate light gaps.

How They Work:

  • Mounted vertically on either side of your window frame
  • Create a channel that traps and blocks incoming light
  • Ideal for use with blackout window blinds

Benefits:

  • Sleek, minimal appearance
  • Effective for total blackout
  • Durable and long-lasting

2. Install Wraparound Curtain Panels

Adding wraparound curtains over your blinds can double up your defense against light.

Steps:

  1. Mount a curved curtain rod above your blinds
  2. Choose thick, blackout curtain panels
  3. Ensure panels are wide enough to wrap around the sides

Bonus Tip: Opt for thermal curtains for added insulation.

3. Add Magnetic Strips or Velcro

For a more DIY-friendly option, try sealing the sides of your blinds with magnets or Velcro strips.

MethodInstallationEffectivenessCost
Magnetic StripsModerateHighMedium
VelcroEasyModerateLow

How to Apply:

  • Attach one side of the strip to the edge of the blind
  • Attach the corresponding strip to the window frame
  • Press together for a snug, light-blocking seal

4. Use Foam or Weatherstripping Tape

A cost-effective solution is using foam tape or weatherstripping to block out side light.

Pros:

  • Affordable
  • Easy to apply
  • Helps with insulation, too

Instructions:

  1. Measure the side gaps
  2. Cut the tape to size
  3. Apply along the edge of the window frame or blind

This method works especially well when combined with blackout window blinds.

Bonus Tips for Maximizing Darkness

Aside from addressing side gaps, here are a few more tips to get that pitch-black effect.

  • Use a double-blind system: Layering two blinds (e.g., a blackout roller and cellular shade) can eliminate all light
  • Add a cornice or valance: Blocks light that creeps in from the top of your blinds
  • Apply tint film to windows: Reduces glare and supports the blackout effect
  • Choose blinds with side tracks: Some blackout window blinds come with integrated tracks to block all side light

Common Mistakes to Avoid

When trying to block light, here are some mistakes that can limit your success:

Choosing blinds that are too narrow

Your blinds should extend at least 2–3 inches beyond the window frame on each side.

Overlooking the mounting style

Inside mounts tend to let in more side light. Opt for outside mounts when possible.

Not pairing blinds with curtains

Curtains add an extra barrier and also elevate the look of the room.

Best Types of Blackout Window Blinds for Light Blocking

Not all blackout blinds are created equal. Some are specifically designed to eliminate light leakage.

  1. Zebra Blinds with Side Channels
  2. Roller Blackout Blinds with Cassette and Side Rails
  3. Honeycomb Cellular Shades with LightLock technology

Each option is ideal if you’re serious about learning how to block light from the side of blinds effectively and stylishly.

Ready for a True Blackout Experience? We’ll Make It Happen

Don’t settle for blinds that leave you tossing and turning at night. If you’re serious about achieving a truly dark, peaceful space, it’s time to upgrade to blackout window blinds that do more than just cover your windows—they seal out light from every angle, including those annoying side gaps. Whether you need expert advice, custom solutions, or professional recommendations, East End Blinds is here to help. Contact us today to find the perfect blackout solution for your home and experience the difference complete darkness can make.