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Window Screens Don’t Fit Properly – How To Fix Them

I recently bought a brand new window screen after putting it off for too long, and while I was a little surprised at just how many styles and sizes were available to choose from, the annoying part came when I got home and ended up trying to jam it into place because it was a little smaller than I anticipated.

Window Screens Don’t Fit Properly

Take it from me, there’s no worse feeling than buying a new window screen or refitting an older one, and then finding that it doesn’t attach the way it should to a window, and while there are a few reasons why this might be the case, there are also multiple ways you can get around it so that you can have a protected window in no time. 

If your window screens aren’t fitting as they should, here is what you should consider doing before throwing them away. 

Window screens can easily warp and become damaged over time due to the temperature, rusting, and any harm caused by pets, but the good news is you can easily adjust them so that they can fit with rope caulking, or you can even use a knife to trim it down or to widen the frame. 

Reasons Why A Window Screen Won’t Fit

This mainly applies to window screens that you have already used for an extended period of time, and that you’re trying to refit elsewhere in the house, however, it is also relevant to any screens that you have bought second-hand

Pest Damage

One of the most popular reasons why people will buy a window screen is to keep nasty critters and insects out of their house, and while the mesh design is perfect for this, there are still a few animals that love nothing more than to chew around the sides of the screen which can end up making it harder to fit. 

If they chew in the middle, it can also cause the mesh to sag which adds more weight to the screen, making it harder to fit into place. 


While window screens are designed to have a long and lasting lifespan of around 10 years, they still can’t escape becoming brittle and rusting over time if they are constantly used and especially if you don’t regularly clean them.

This means that if you’re trying to move an old window screen around, the outside frame can be a little too frail or damaged to re-insert. 

Exposure To Sunlight

It’s inevitable that window screens are going to be in direct contact with at least a bit of sunlight during the daytime, however, as your window screens begin to age, the UV rays will begin to take their toll on them, warping the screens and weakening their durability.

It can even get to the point where the screen becomes so weak from the heat that a simple gust of wind or a small flying piece of debris will tear right through it, so considering how fragile the screen becomes, you can imagine how much harder it can be to install it into a new window space. 

Incorrect Measurements 

If you’ve bought a brand new window screen rather than re-using an older one, and you find that it isn’t slotting into place as it should, the biggest reason why this may be happening is down to a mistake in measurements

If you haven’t taken the time to measure your U-channel (height) or the L-channel (width), then you’re basically going to be running on blind luck when picking up a new screen since there is no guarantee that it will actually fit properly. 

What To Do If A Window Screen Won’t Fit

Window Screens Don’t Fit Properly

Check The Exterior, Not The Interior 

One of the biggest mistakes people will make when trying to fit a new window screen is looking at the gaps from the interior side of the screen.

Make sure that you place the screen in and then go outside to check that it fits tightly against the exterior lip of the window. 

This is a common mistake that will lead people to believe that their screen isn’t tight enough when in reality, it actually fits perfectly fine but can seem a little off when viewing it from inside the house. 

Apply Some Rope Caulking

Rope caulking acts as a great seal for a window screen, so placing it around the interior edge of the screen is a quick and fairly easy way to tighten the whole thing up if you find that it’s a little too thin or fragile for your liking. 

Always remember that you want water to drain out from the front of the screen, so it can be worth not sealing this compartment and just using the caulking on the sides instead. 

Use A Butter Knife

If you are having trouble keeping the screen slotted into the gaps at the side of the window, consider using a butter knife to jam them in.

Do this until they it hits the exterior frame of the window, and it should then be slotted in and tightened up. 

This is a method that works especially well with screens that are a little bigger than you anticipated when you first bought them.

Check The Material You’re Sticking It To

Many window screens will use adhesive tape which will only stick to clean surfaces, so if you’re attempting to attach it to brickwork or loose paint, you will have a much harder time getting it to fit. 

Make sure that your surfaces are completely clean and wiped down before attempting to install the window screen, and be aware of the material you’re trying to attach it to. 

Trim The Screen Down

The good news is that if you have a window screen that is a little too big, it can be trimmed down pretty easily. When the screen is in the frame, the excess inches of the screen will appear at the top.

Take a sharp utility knife, and run it straight down the excess to remove it. Make sure to slide it through the top of the channel and don’t touch the spline.


Fitting a window screen can already be challenging enough, so if you do run into any issues, rather than getting annoyed and buying a new screen altogether, try a few of these methods to have your protective screen tightly attached in no time.

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