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How long does vinyl siding last?

I get asked how long does vinyl siding last or what is the lifetime of my vinyl siding on a weekly basis when meeting with clients to discuss the siding options for their home. It's either in the context of is my vinyl siding still good or should I replace my old siding with new vinyl siding. Of course, how long your vinyl siding lasts has a lot to do with how old it is.

The old days of vinyl siding (pre-early-2000s).

Back in the early days, vinyl siding was manufactured through a co-extrusion process in 2 layers, like a veneer. The base layer, or substrate, was a PVC blend. The top, thinner layer, called the capstock, was a color blend that often contained lead. The base substrate of the vinyl siding was blended with calcium carbonate in order to reduce the cost. This also balanced the titanium dioxide used in the capstock ensuring parity during the extrusion process. The problem with this method and composition was 3 fold:

  1. The mixtures used in both the substrate and the capstock were not consistent. Consequently, when exposed to UV from the sun, it would fade at different rates. This caused a blotching effect, and is easily identified on older vinyl siding through a visual inspection where there are lighter and darker areas exposed to the same levels of UV on the same panel of siding.
  2. The Calcium Carbonate used in the vinyl sidings substrate and the Titanium Dioxide in the Capstock would oxidize over time. Depending on how much exposure the to sunlight the vinyl received, it could oxidize as soon as 5-10 years and as far off as 20 years. This eventually caused the vinyl siding to become brittle and form a calcium carbonate film over the exterior surface of the vinyl siding. Again, this is very easily identified visually and manually as it appears as a white chalky film and, upon touching it, transfers onto your fingers and clothes. This oxidation is very difficult to clean off of your vinyl siding, and, because it is within the base mixture, will continue to reappear as time passes.
  3. Since the color was only in the thin capstock layer of the extrusion, scratches would expose the underlying substrate of the vinyl siding, which was a different color and causing an unsightly scar. Older vinyl siding commonly used through the 1980s through early 2000s has a shelf life of approximately 20-25 years.

So, if your vinyl siding presently has the above characteristics, then it is probably time to replace it with a newer product.

Why is my vinyl siding is fading (post-early-2000s)?

The newer formulations of vinyl siding manufactured by the large corporations has changed significantly in process and quality since that time. Vinyl siding is now regulated by ASTM, which requires specific standards and tolerances be met. As such, a much more reliable and predictable finished product is provided. The extrusion process is now mono-extruded. This means that the color is blended throughout the PVC mixture of the siding panel. It ensures a consistent level of fading throughout the vinyl siding panels and wall area. Vinyl siding today, in most cases, carries a limited, non-pro rated transferable warranty for fading. It should be noted, however, that while there is a very strong fade warranty, the warranty actually doesn't cover fading in and of itself. Instead, it is a guarantee that AS the vinyl siding fades through the UV exposure process, it will fade uniformly, and consistently. It can be expected that your new vinyl siding should last in excess of 30 years.

The current problem vinyl siding is facing today, isn't fading and oxidation. It's the melting caused by UV light being reflected onto its surface from newer adjacent windows containing a UV reflective film (that's used to provide higher energy efficiency, i.e., helping keep homes cooler in the summer and warmer in the winter). Vinyl siding is manufactured for a heat tolerance in the neighborhood of 165f, however, the UV tinting acts like a reflective magnifying glass, throwing off a laser beam that hits around 180f or more. This causes the vinyl siding to melt as the sun moves across the horizon. You can identify this as being the cause of the fading as the vinyl siding panel is distorted from it's original shape, tracking vertically across many panels. The only way to fix this issue is to find out which windows are the cause and replacing the glass absent of the tinting, paying your neighbor to replace theirs, changing the siding to a fiber cement such as James Hardie, OR waiting for the Sun to collapse into a Dwarf star.

Simply replacing the vinyl siding alone is insufficient, as the UV tinting will continue to melt in those affected areas as time passes.