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Spline Rot and How to Fix it

What is spline rot?

Have you noticed lately that the screens in your windows or your porch have started to become a little looser than you remember it being when you first moved in? Do your screens appear to be sagging and rippling in the wind on occasion? Or—perhaps you\'ve noticed worse, that the corner of your window or porch screens has come undone from its frame. If you aren\'t sure why this is happening, we can guide you in figuring out why it happens and how to fix it.

Your screen\'s spline has probably gone brittle, rotted, or needs a replacement. But first, let us start at the basics so you will be armed with the right know-how to repair it.

What is a spline?

In almost all contemporary or modern screens, whether window, patio, door, or pool screens, you will find that the screens are secured in place with the help of an object called a screen spline. Most window splines have a standard format with a similar look made of a typical rubber tube-like structure. The spline is pressed into a groove inside the screen frame or the frame where the screen has been installed. This is the easiest way to lock a screen in place.

Quality screen spline should have a very long shelf-life as well as being able to resist being outdoors for many years. However, since spline is exposed to constant sun, rain, dampness, wind, and the environment it can deteriorate over the years of this exposure. This deterioration can happen faster in particularly very hot, very humid climates where the spline is continuously exposed to extreme heat and moisture.

What is spline rot?

Spline rot is a general term that covers the deterioration of the spline when it has been exposed to years of heat, sun, wind, rain, and moisture. It is especially prevalent in splines that may have been created using subpar materials or questionable quality materials, which may contribute to the spline breaking down even faster.

If your screen spline is made of lower quality rubber, you might experience spline rot—more commonly known as dry rot. Dry rot is caused by a fungus that attacks organic materials that contain cellulose, like wood and cotton. Since rubber is a natural material, this fungus can be responsible for the decaying of your spline. If your rubber spline is synthetic, it should share the same properties as natural, however, a reputable synthetic rubber manufacturer will ensure that during the rubber making process to impart certain additives that will ensure their formula can withstand and resist damage as well as heat for longer than natural. Yet, synthetic rubber can eventually succumb to spline rot.

Natural or synthetic, rubber is a polymer, and its chains of molecules are vulnerable to many of the same factors that affect all polymers. The sun (ultraviolet radiation), temperature extremes, ozone, and oxidation all can affect the window spline.

The rubber that gets regular exposure to extremely high or low temps or prolonged exposure to UV radiation begins to cause rubber\'s molecular chains to break down over time.

Before replacement: understand spline removal issues

Before removing your old spline to upgrade with new, there are a few typical issues you may encounter when trying to remove it. The aged spline can be very vulnerable to cracking, which means that should you try to remove it, you may find it breaking into several pieces. Pulling too hard to remove old spline may also damage the settings of the groves along which your screen is set, which is something you do not want to do if you wish your screens to sit flush in the frame.

Occasionally, in the hotter regions, the spline may have melted in areas and fused along the edge of the screen which then makes the process of replacement even more tedious. If you aren\'t careful in removing your old spline, small bits of it can stick within the frame or on the screen—making either installing a new screen, or the old screen with new spline difficult or nearly impossible.

Spline removal can be done in the right manner at home by paying attention to two important things: identifying the spline removal point and careful, slow removal.

  1. Find and identify the ending of the spline which should be easily visible due to it being slightly thicker at the edge. This is the only area in which you should be able to gently pry upward with the screwdriver tip.
  2. Access the underside of the spline removal point you\'ve just identified and try and lift it, pushing it out of its groove. Push out at least 20 inches, as you need to have a good length to grab to pull the rest of the spline out.
  3. Pull the spline out with careful, even pulling, and slowly to avoid breakage.
Replacement Spline

When it is time to replace your old spline with new, we highly recommend choosing a spline made with exceptional quality materials that are made to withstand being outside in the moisture and sun. This is to ensure that you will not have to be constantly finding your window, porch, door, patio, or pool screens hanging improperly and having to constantly replace the spline.

Finding the right screen spline can often be a challenge, especially if there is no documentation on what previous size spline has been used before. Luckily for you, at Quality Window Screens, we have experts in our superb customer service representatives that are happy to help you find precisely what you need.

Not only can we help find what you need, but we also have a large array of the industry\'s finest splines and window treatments for both professional contractual work and homeowners looking to do DIY improvements. From 100 feet of 5/16 flat retainer spline to serrated spline, window screen materials, a Do It Yourself Kit with every item you need, and highly specialized spline tools to help you use and cut it yourself.

Contact us anytime if you have any questions about our spline, or any of our products and have your screens looking beautiful and flush in no time.