Screen Spline Information

Very often when you repair a screen you can reuse the old spline. But there are occasions when you cant because the old stuff is in such bad shape. Or, you might want to make a whole new screen frame with all new materials. You might also encounter old style flat screen spline or even aluminum or steel splining and need to replace it with something more easily available

Spline is a available in quite a variety of shapes and sizes for the window industry. The average hardware store or even big box store, stocks only a couple of sizes. Most likely the frame you have to work on requires the size they dont have.

Types of Splining Materials

Round Polyfoam

Round EPDM

Round Hollow Core Vinyl

Vinyl "T" Splining

Flat Screen Splining

Square Aluminum

Round Steel

Your local glass shop may well sell you the right size you need, just remember to bring a sample of the old that you removed so you can be sure to get the size right. If you still cant find the right size, check the link at the end of this page.

Round Polyfoam

Spline comes in rolls that look like electrical wire, except it is solid all the way through. In the big box stores you will most often see "Polyfoam" which is like foam rubber except with very small air bubbles. It is available in sizes measured in decimals of an inch. For Example #140 is .140 of an inch. Polyfoam is the the easiest spline for the novice to work with.

The most common sizes or diameters in Southwestern Ontario, Canada, where I live are .160, .180, .200 and .250 inches diameter. I believe the above sizes are pretty common across North America too.The sizes used depend on who the predominant supplier of windows was when most of the houses were built in your area.

The .250 size replaces the 1/4" aluminum splining that was used in houses built in the fifties and sixties. This size is particularily easy for the do-it-yourselfer to roll in.

Round EPDM

Splining is made in many different materials . There is EPDM which is a kind of very flexible rubber. EPDM is a longer lasting material than the polyfoam, but like all plastics, it can become brittle with exposure to the sun. One useful property of EPDM spline, is that you can stretch it a little as you roll it in the spline channel, making it easier to roll in. EPDM is more commonly seen in screens with very small spline diameters like .120"

There is also hollow core vinyl. Hollow core vinyl can be stretched as you roll it in like EPDM spline. This helps if the diameter is just a little too big for the frame you are working on. Polyfoam is best for the beginner though because it can be used in wider variety of frame styles and is easier to roll in.

"T" Spline

There is also "T-spline" that is used a lot in the very thin screen frames used in aluminum storm doors. This is usually made of extruded vinyl and its cross section has the shape of a letter "T". It also is available in the same size descriptions as polyfoam. When you roll this in you have to get the flat top of the letter T to lay down in the spline channel. That way it locks the screen material in place much more surely than regular polyfoam spline. With the T stuff however, you have to have exactly the right size, otherwise it just will not work.

Most "T" spline is Black coloured Vinyl. In the past some window manufacturers used white vinyl. Trouble is, the white vinyl became so brittle in the sun so that when you try to remove it, it just turns to powder!. If you have white vinyl spline to replace, count on spending quite a while to scrape it out.

Flat screen spline and other strange shapes

Some window manufacturers have used weird and wonderful shapes in their custom screen doors in the past. Many screen doors built in the 1950's used gray vinyl flat screen spline to hold the screen in. Flat screen spline is not easily available but in some cases you can substitute "glazing stop" vinyl and it will work fine. Glazing stop vinyl is normally used to cover the edges of the exposed glass around the perimeter of aluminum windows. Check with your local glass shop to see if they have glazing stop vinyl similar in size and shape to your flat screen spline.

Other shapes you may run into are hollow 1/4" square aluminum splines used in windows from the sixties. This can easily be replaced with 1/4" diameter round polyfoam spline.

Some screens from the 1940's used round steel bars to hold the steel screen cloth in. This is certainly reusable if you don't mind hammering it back in again. No question these screens are 10 times stronger than anything available today. Personally though I find its easiest to replace the steel with 1/4" diameter polyfoam and regular fiberglass screening.

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