TPO Roofing Material
TPO Roofing Material (Thermoplastic Polyolefin) is one of the most commonly used roofing materials in the country. It was originally designed and is still in use today as a lining in swimming pools. And it’s well suited to that role. But to the detriment of people who use roofs everywhere, someone who must have had warehouses full of this stuff had the “brilliant” idea of employing it in the roofing industry.
As a result, TPO roofing materials have been in use and a state of constant replacement for decades. While they were originally designed with some semblance of quality in Europe, here in the States manufacturers have cheapened the material over generations to make it more affordable and easier to install. The result of this de-evolution has been a material that the roofing industry loves, due to its being extremely affordable and needing to be removed and reinstalled much more regularly then traditional roofing materials, but that causes untold problems for property owners.
As far as thickness and durability are concerned with a TPO roof, it’s at the bottom of the food chain. It is so easily punctured that it cannot be walked on, which is for the best considering it’s so slick that it could double as a slip-n-slide. If a hole does form, which is common, it is nearly impossible to locate unless the hole is huge. Against the elements, TPO loses 1-2 mils of thickness per year. The top ply, which is the only layer of protection, averages a thickness of 15 mils. That means, in a best-case scenario where a TPO roof has been installed and maintained properly, its maximum life expectancy is 15 years. Most however will only last 7-10 years.
Besides the inexpensive price tag, there is one other advantage in using TPO as a roofing material. It’s white, giving it a fair reflectivity rating and saving some energy in cooling the building. However, in colder climates TPO requires a thick insulating layer underneath because the material is extremely thin. So thin in fact, that light is able to go completely through it and nourish mold and algae growth underneath your roof. Over time this UV light penetration will break the material down at the molecular level and make it as brittle as a plastic cup. And not even like one of those indestructible sippy cups you give to toddlers, more like the kind they give away at sporting events.
In terms of installation, TPO is a thermoplastic material. This means that it is installed by means of hot-air welding. Due to the shoddy manufacturing and thin plies, the welded seams are actually stronger than the surface of the material. As you can imagine, it’s not easily maintained. Since leaks are so hard to find, repair often involves simply hot-air welding a massive piece on top of the old one. That of course assumes that the roof can be saved.
Most of these types of materials have a wicking scrim, which is a woven layer underneath the top layer of the material. If the scrim gets wet, the membrane delaminates and comes apart from the top layer. At this point, you have a wet sweater shielding you from the elements. And to make this flaw worse, some TPO materials now come with self-adhesive seams instead of the more common hot-air welded seams. This is a fancy way of saying your roofing material is peel-n-stick, and makes it even more likely that large amounts of water will find their way into the scrim layer.
If you weren’t already taking a gamble in putting TPO on your roof, think about this: you’ll have a hard time finding someone to warranty this material for more than 2 years. Some will do 7 years; but when higher quality materials can be insured up to 30 years, don’t you think that’s sending a pretty clear message?
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