Hey there, it’s Mia here from the 120 Roller Blind team—yep, the folks who’ve been helping apartments and small businesses ditch clunky window coverings for sleek, easy-to-use roller blinds for years. Today I’m walking you through exactly how to install our 120 Roller Blind on a sliding window, no fancy tools or construction degree required. I’ve installed like 50 of these myself (back when I was doing on-site support before moving to customer care) so I know all the little hiccups that trip people up—like forgetting to check if your window frame’s solid, or measuring wrong and ending up with a blind that’s too small. Let’s dive in. 120 Roller Blind
First, let’s talk pre-install prep, because skipping this part is how you end up frustrated mid-project. The biggest thing with sliding windows specifically? They’re not your standard casement or double-hung window—so you can’t just eyeball the fit like you would for a regular window. I always tell customers to grab two things before you even touch your blind: a tape measure (the soft fabric one works great, but a rigid metal one is better for straight edges) and a level tool (even a $5 torpedo level from the hardware store will do).
First, double-check your blind specs to make sure it’s made for sliding windows. Our 120 Roller Blind line has two common sizes for sliding frames: one that mounts inside the window recess (inside-mount) and one that sits on the trim outside the recess (outside-mount). Sliding windows usually have a recess that’s at least 1.5 inches deep—if yours is less than that, outside-mount is non-negotiable, because you won’t have enough space to screw the brackets without hitting the window track. I’ve seen people try to cram an inside-mount blind into a 1-inch recess, and it just doesn’t roll up right—don’t be that person.
Next, measure twice, cut… wait, no, measure three times. For inside-mount, measure the width of the recess at the top, middle, and bottom. Sliding windows often have slightly uneven tracks, so if you go by the top number, you might end up with a blind that’s tight on one side and gaps on the other. For height, measure from the top of the recess to the windowsill, plus an extra ¼ inch if you want the blind to cover the gap when rolled down—too long and it gets stuck under the sill. For outside-mount, measure the total width you want the blind to cover (usually a few inches wider than the window frame, so it blocks light from the sides) and height from the top of the trim to where you want the blind to end. Our 120 Roller Blinds are custom-cut to order based on these measurements, so send us exact numbers, not “about 36 inches wide.”
Also, clear the area! Take off any window screens, remove the sliding sash from its track temporarily if you need—this makes drilling so much easier. I know it’s a hassle, but you don’t want to drill a hole in your screen by accident. Lay down a towel or cardboard under your work area too—drilling shavings and screws are way easier to pick up than chasing them across hardwood floors.
Now, let’s talk tools. You don’t need a full toolbox—just a Phillips-head screwdriver (powered is way faster, but manual works), a drill with a small drill bit (1/8 inch is perfect for wood or vinyl frames, 3/16 if you’re drilling into metal window tracks), and a pencil for marking. No fancy stuff, I promise.
Okay, time for installation! First, decide where your brackets go. Brackets are the little L-shaped pieces that hold the blind up—most 120 Roller Blinds come with two, but for windows over 60 inches wide, we throw in a third free, just ask! For inside-mount, line the bracket up so the back of it sits flush against the back wall of the recess, and the front sits just inside the window track. Mark the screw holes with your pencil—make sure the two brackets are level, or your blind will roll crook every time. I always test this by resting a level across the top of the two bracket marks; if it’s not level, adjust the left or right mark until it is. For outside-mount, line the bracket up on the outside trim, same level rule applies—you want the blind to be straight, not tilted.
Pro tip: If you’re drilling into vinyl or aluminum (super common for sliding window frames), use a small drill bit and go slow—don’t push too hard, or you’ll crack the frame. I learned that the hard way when I drilled a hole through a customer’s vinyl frame, and had to patch it with caulk. Oops. For wood frames, you can drill a little pilot hole first to make screwing in the brackets easier, no cracking risk there.
Once your brackets are screwed in tight, it’s time to attach the roller blind. Most 120 Roller Blinds have a front mounting rail that slides into the brackets—you’ll hear a little click when it’s locked in. Give it a gentle tug to make sure it’s secure, no wiggling. Now, if you have a control cord (most of our roller blinds come with side cords for adjusting, no motor needed, unless you get the smart version), feed the cord through the little guides on the side of the blind. Make sure the cord is on the side that’s easiest for you to reach—don’t put it on the side of a cabinet if you’ll have to crawl behind it to adjust every day.
Wait, if you have a sliding sash, you need to put that back now before testing! Slide the sash back into the track, make sure it moves smoothly, then test the blind. Roll it up and down a few times—if it’s sticking, don’t panic. First, check if the brackets are level (that’s almost always the issue). If they are level, adjust the side controls: most of our blinds have a small tension adjuster on the end cap—turn it a little with a screwdriver to tighten or loosen the roll. I had one customer whose blind kept slipping down, and it was just the tension being too loose, took 10 seconds to fix.
Also, quick note for screen room sliding windows (like sunrooms or porches): if your window has a screen that slides with the sash, you’ll want to install the outside-mount blind. Inside-mount will block the screen from moving, trust me. We make a special version of the 120 Roller Blind for screen rooms that’s slightly shorter so it doesn’t interfere with the sash, just let us know if that’s what you need when you order.
Now, let’s go over common mistakes people make so you can avoid them. First, drilling into the window track for inside-mount: don’t do that! The track moves when you slide the sash, so screws in there will pull out and your blind will fall. We provide special screws for recess mounting that are long enough to go into the frame wall behind the track, not the track itself. Second, not taking off the window screen: like I mentioned earlier, screens are flimsy, and a drill bit can punch right through them, leaving a big tear. Save yourself $10 for a replacement screen and take it out. Third, measuring wrong: I can’t tell you how many people text us a blurry photo of their window and say “make it fit this” and it’s either too wide or too narrow. Just use a tape measure, write down numbers, and double check. We’re happy to help with measurements too, if you send us clear photos—no judgment, I mess up measurements all the time when I’m hanging blinds in my own house.
If you get stuck mid-install, don’t worry—our customer support team is here 7 days a week, no waiting 3 days for a reply. We can walk you through tension adjustment, bracket leveling, anything. Just send us a message with a photo of your setup and what’s going wrong, and we’ll get you sorted.
Now, when your blind is all installed and working perfectly, that’s the good part—no more glare in the morning when you’re trying to sleep, no more nosy neighbors peeking in, you can adjust it to let just the right amount of light in. Our 120 Roller Blinds come in 20+ fabric colors, from light-filtering sheer to blackout, so you can pick whatever fits your space. Whether you’re updating a rental apartment, a tiny home, or a small business space, these blinds are easy to install, durable, and way cheaper than hiring a handyman.
If you’re thinking it’s time to swap out your old sliding window covers, we’ve got you. You can order custom-sized 120 Roller Blinds right through our site, and we ship them out in 3 business days. No hidden fees, no complicated returns—if you get it and it’s not what you wanted, just send it back, no questions asked. Our team is here to help with every step, from choosing the right size to installing, so you don’t have to stress about it.
Last thing: once you have your blind installed, don’t forget to do the little maintenance thing every few months—wipe it down with a damp cloth, check that the brackets are still tight, and adjust the tension if it starts slipping. They’ll last years if you take care of them, no problem.
If you have any questions, or want to place an order, just reach out to our team whenever. We’re always here to help. Don’t hesitate to contact us for a custom quote or to walk through your installation step-by-step.
Polycarbonate Canopy REFERENCES
- Window covering installation best practices, Home Improvement Magazine, 2023
- Sliding window fitting guides, National Home Builders Association, 2022
- Roller blind tension adjustment tips, Window Treatment Industry Association, 2021
Guangdong Fanxi Youpin Intelligent Technology Co., Ltd.
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