single hung screens

Measuring Instructionsoutermost

From inside your home, open your window and find an area on the outer most portion of your window frame that has what appears to be “U-channels” that run along either the top and bottom, or along both sides of your window frame. There will be a L-channel on the other 2 portions of your window. This area is where your screen frame will go. The U-channel is designed to ensure that the screen frame will not fall forward/outside, or backwards/inside. It is also the portion where your hardware will be placed. The L-channel is to ensure your screen does not fall forward/outside.l-channel

Measure the width of the U-channel to determine the “frame choice” needed. For a single hung window the U-channel width will be 5/16” about 90% of the time. The other 10% would be either 1/4”, sometimes 7/16”, and very rarely maybe 3/8” (if 3/8” you will need to substitute a 5/16” frame for your
window screen. See “frame choices” for more detail).

Now you will need to determine your screen width and height. When taking these measurements keep a few things in mind:hardware choices, etc.

The U-channel can be on the widths (sides), or heights (sides) of your windowsill.

The purpose of the U-channel is to keep your screen from falling out, and hold your hardware. Knowing this, understand that all the screen needs to do is stay within the U-channel. The screen should not fill the entire U-channel on both sides.

This is important to understand during the measuring process, because you need to know that the screen width/height has to be less than the distance of the full depth of U-channel to the full depth of the U-channel on the opposite side in order for you to install the window screen later.

Actually during installation, you will need to push the screen all the way into the deepest U-channel so it can clear the top ridge of the opposite U-channel. Then you can release the screen, which will allow the screen to rest in both U-channels.

The L-channel portion is not nearly as difficult, as you can see that you will not need to “clear” a portion of the channel during installation.


Place your tape measure completely inside THE DEEPEST U-channel (getting full depth of channel), and measure across to the upper ridge of the U-channel on the opposite side (do not go into this U-channel at all).

If you determine you will need any hardware added on the u-channel portion of your screen, deduct 1/4” from your measurement.

If you determine you will NOT need hardware on either u-channel portion of your screen, deduct only 1/8” from your measurement.

The additional deduction for hardware is to allow for the thickness of the hardware.

After making the appropriate deduction, you have your screen dimension for the u-channel portion of your screen.


Your L-channel most of the time is just that….an obvious L-shaped part of your window frame that your screen will rest against. You will find it at the outer most portion of your window sill. However, on some model windows you will see what appears to be a wide U-channel where one portion of the “U” is longer than the other. The inter most portion of the “U” is actually the back part of your window track. The longer portion of the “U” should be the outer most portion, and is the L-channel we want to focus on.

Measure from the inter-most portion of one L-channel to the outer-most ridge of the opposite L-channel. Measure in 2 different areas to ensure area is “in square”.

Similar to the U-channel, it is important not to cover the entire span from inter-most to inter-most portion of L-channel. It is only important to ensure that your screen frame covers the distance beyond both portions of the L-channel. During installation, you will have to move your screen frame all the way to one side, and allow the other side of the screen frame “clearance” from the opposite L-channel ridge, then move screen frame back to ensure screen frame covers a portion of both L-channels.

Deduct 1/8” to 1/4” from smallest measurement.

Make sure to allow for additional deduction of another 1/8” if needing hardware on L-channel portion of your screen. (very rare)


It is critical that when ordering we know where to place your hardware. Some window screens will have hardware on the widths (top/bottom), some on the heights (top/bottom), and some on both.

When determining hardware needs and location, and based on what you noticed during the measurement process, please take care when placing order that your hardware needs are placed on the correct widths, or heights, or both.

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