how to stop light coming in through the side of blinds

How To Stop Light Coming In Through The Sides Of Blinds

I’ve been doing some research into how to stop light coming in through the sides of blinds. I love sleeping in on a Saturday, but it’s not easy when the sun’s glare starts making its way past my blinds. So I’ve found some solutions which are cheap and cheerful, and others which require a little more investment, for more high-end results.


Why Are My Blinds Leaking Light Around The Sides?

Firstly, let’s address how this becomes a problem in the first place. Blinds are meant to block out light, right?

Problems with light coming round the sides of blinds are usually associated with inside mount blinds. That is, blinds which sit inside the window opening, rather than in front of it. Inside mount blinds must be made slightly smaller than your window opening, in order to move up and down without friction against the wall on either side. The biggest flaw of this design is that the gaps on the sides of your blinds also let in sunlight.

Warping and sagging can also create light gaps at the sides of blinds. Warping is when your blind’s slats bend or bow in response to heat or moisture. As the slats bow at the center, a wider gap starts to form between the edge of the gap and the wall. You’ll also notice more light bleeding through the middle of the blind too, because the warped slats no longer sit flush against each other.

how to stop light coming in through the side of blinds

Now let’s look at how to block that unwanted peripheral light reaching round your blinds.

How To Stop Light Coming In Through The Side Of Blinds: Easy Ways

If you’re looking to block gaps around existing blinds, you have two easy options:

  • Layer your blinds with drapery
  • Install light gap blockers

Layering Your Blinds With Drapery

An effective way to stop light from seeping through the sides of your blinds is by layering them with curtains or drapes. Drapes are usually heavier and exclude light more efficiently than curtains, but you can get lightweight curtains with blackout properties as well, if drapes aren’t your style. Apart from the functionality, layering your window with drapery also adds aesthetic appeal, blocks drafts, and reduces heat loss through the window.

Installing Light Gap Blockers

Light gap blockers are L-shaped vinyl strips you install inside your window opening. The strips adhere to your wall or window frames, and stick out perpendicularly, so that they overlap with the blind.

Installation is an easy DIY project. Light-blocking strips come in a range of lengths which you can easily trim to fit your window size. Peel away the sticky backing and secure the strip on the sides of your window opening. You do not need specialized tools to trim the vinyl strips; a pair of kitchen scissors or a hack saw will suffice. You can install the light blockers in front of or behind your blinds, but for effective light blocking, install the strips as close to the blinds as possible.

Light blockers are readily available; you can buy them from window treatment shops and vendors. Some vendors offer free light blockers with specific blinds and shades.

How To Stop Light Coming In Through The Side Of Blinds: Alternative Solutions

If you have the budget, and you don’t like drapes or you’d like a solution which looks more high-end than light blocker strips, then you might prefer one of these solutions:

  • Ask for a professional refitting
  • Install new blinds
  • Get custom blackout blinds
  • Switch to an outside mount configuration

Ask For Professional Refitting

If you brought your blinds from a company who measured, manufactured and fitted the blinds for you, then check what terms you agreed about the size of the gap at the side of the blind. If the gap is in excess of what they told you to expect, then you might be able to make a case that they have made their product too small, and ought to replace it.

Eliminate Light Gaps With New Blinds

Maybe you are in the market for new blinds and wish to prevent lights from coming in through the side of your blinds.

Below are tips to block unwanted light with new blind installation:

  • Opt for custom blackout blinds
  • Opt for outside-mounted blinds
  • Avoid blinds that warp or sag easily

Get Custom Concealed Blackout Blinds

Custom concealed blackout blinds are a solid solution to light gaps. They are roller blinds, installed with a custom frame that hides the mechanism at the top. When lowered, the blinds travel down discreet channels in the window recess, to stop light getting around them. In the video at the top of this article you can see a talented home renovator making their own bespoke frame to conceal a roller bland and stop light leaking around the edges. But for most people, this is a job to leave to the professionals!

Spending extra for this solution if you can afford it is ideal in bedrooms, nurseries, and media rooms, and homes with an ultra modern, minimalist vibe.

Switch to an Outside Mount Configuration

Outside mount blinds are installed outside the window recess and are made oversized to cover the entire window. Outside-mounted blinds may hide your decorative molding, but they offer complete window privacy and eliminate light gaps more efficiently.

All types of blinds can be mounted like this, but blinds which hang flush to the wall will be the most effective at blocking light around the sides.

Avoid Blind Materials That Warp Easily

Warping is when blinds bow or bend inwards. This causes light leakage around the sides and from the middle, and it spoils the look of them too. Real wood blinds warp when exposed to humid conditions. So it is pointless installing them in wet or humid rooms like kitchens and bathrooms. Large roller blinds in flimsy materials can sag and curl at the edges over time as well. If in doubt, ask your vendor to recommend which textiles will last the longest.


The fact that your blinds are leaking on their sides does not mean you have to dispose of them. With the strategies below, you can save your blinds while eliminating light gaps:

  • Layer the blinds with blackout drapery
  • Install light-blockers
  • Seek professional refitting

If you are looking to eliminate light gaps with your next purchase, here are some helpful tips:

  • Opt for custom blackout blinds
  • Opt for outside-mounted blinds

In the end, we added outside mounted roman blinds to our bedroom windows, which generously overlap the window recess. And the effect was just perfect – not only are they beautiful to look at, but the amount of light coming into the room on a Saturday morning is dramatically less than it was before. And my lie-ins are better than ever!

Are your window blinds letting in light through the side?

Let us know how you solve it using the comments box down below!

More About Blinds

Similar Posts

Leave a Reply

Your email address will not be published.