Industry Thickest 6 mil Vapor Barrier
BOTTOM LINE: Thermal Guardian premium spa covers last longer in large part due to their industry-leading 6mil vapor barrier film and superior sealing technology.
Unfortunately, spa covers do eventually get waterlogged and become too heavy to use. We may not be able to control whether it happens at all, but we can definitely increase the cover's defense and push that water saturation date back!
Here's the what, why and how of spa cover waterlogging and how our Thermal Guardian outperform the competition. It all starts with the vapor barrier film and how it is sealed.
FACT: Expanded PolyStyrene (EPS) foam cores will become totally saturated with water when used in a spa cover application.
Why? Even though the beads are closed-cell, the structure of EPS is not. Depending upon the density of the board (pounds of bead per cubic foot), a foam core has honeycomb channels in between the molded beads. As the water vapor penetrates the foam core and then cools and condensates in its liquid form, the water becomes trapped. Spas form a natural pressure situation that pushes hot water vapor upward. The spa cover is holding that water vapor back.
Imagine a raw piece of foam suspended above a spa. Without any protection, this foam core would be fully saturated in a matter of months. Spa cover manufacturers would obviously go out of business if the cores waterlogged in a couple of months so they need to protect the core. That's where the vapor barrier film comes in. It stops the water vapor from penetrating the foam core.
If this is the case, why does the core eventually still waterlog? The answer to this question can be a couple of things. Some are out of the control of the manufacturer, but some are if the maker is willing invest in technology to produce a high-quality product.
First off, the vapor barrier film is only as good as its sealing technology. We have a hard time believing that some cover manufacturers still tape their film shut, but they do. Here is a breakdown of the technologies employed.
Next, the chemicals you put into your spa to sanitize the water gas off and deteriorate the vapor barrier film. Over time, the film itself is broken down leaving the foam defenseless. Though you cannot stop the chemicals from doing their dirty work, you can toughen up the film. We use a 6 mil linear low-density polyethylene film as our vapor barrier. Compared to the films of covers, our film is up to 3X stronger. Also, by using low-density PE film instead of the more popular high-density film, our vapor barrier degrades more gracefully over time. Did the film on your last cover start coming apart and get stuck in your filter? That's because high-density film shatters as it weakens. Low-density has more elasticity and will not shatter. This keeps the vapor barrier intact longer offer its protection longer leading to longer cover life.