Your Spa Cover's Foam Should Be Tapered!
When we started selling spa covers over 20 years ago, they were flat. Quickly some of us realized that standing puddles of water were not a good thing for spa covers. Hence, the age of tapered spa covers began. For outdoor applications, we recommend a minimum of 2" of fall meaning that the center of the cover should be 2" thicker than the outer edge. This enable the cover to shed water like the roof of a house.
The 5" x 3 " tapered foam cores of the ThermalGuardian Standard and ThermalGuardian Deluxe are GUARANTEED to allow water to roll off the cover and avoid the puddles that will break your cover's expensive foam cores.
Don't get caught spending hundreds of dollars replacing your foam cores by buying a cheap 4"x3" cover that won't shed the water like our ThermalGuardian premium spa covers will.