Our hot tub covers are made with the highest quality, 100% virgin EPS closed cell foam, vacuum wrapped and heat sealed inside of a 6 mil protective barrier. But even our top quality 2 lb foam core panels can absorb water.
Why? Why do spa and hot tub covers absorb water? Many people will say that closed cell foam cannot absorb water, and they point to studies where a piece of foam has been sitting in a jar of water for 20 years in some laboratory. And this is correct. Even submerged in water, at room temperature, most quality closed cell foam will not absorb water.
However! In a hot tub environment, there is a large temperature difference between the top of the cover and the bottom of the cover, in some cases it can be more than 50 degree difference. This creates an imbalance, and makes the warm moist air of the spa condensate on the bottom of the cover, and become aggressive in trying to escape.
Add to this the fact that most spas are treated with chlorine or bromine, or ozone – which can break down the vapor barrier, the closed cell foam, or both.
What’s wrong with a heavy spa cover?
For one thing, the R-value of the spa cover drops dramatically as water is a very poor insulator. Hot tub cover heat loss becomes a real concern when it becomes waterlogged. Secondly, the weight of the water can actually bend the steel reinforcement bar (not on our spa covers, made with 20 ga. steel bars).
It also just becomes a real pain in the butt – if you have to call a second person to help lift the spa cover on and off of the tub. Full of water, a spa cover can weigh several hundred pounds, which can cause injury, trying to move such a large heavy object. It can also damage or break your spa cover lifter.
Causes of a Waterlogged Hot Tub Cover
- Torn foam panel protective barrier
- Deteriorated foam panel protective barrier
That’s it! The 6 mil plastic sheeting that is used to wrap the foam core panels is the main protection against a waterlogged spa cover. Sure, other factors contribute to the problem, like chemistry or broken foam panels, but the fact is – if the vapor barrier is sealed tightly without any gaps or holes, the foam core panels stay nice and dry. Taking care to prevent punctures or tears and chemical deterioration is the best way to keep your spa cover dry and lightweight.
In addition to vacuum shrinking and heat sealed seams (not something all other spa cover makers do), Hot Tub Works spa covers offer a double-wrapped foam core, standard on our “Works” spa cover, and as an option for other covers. Could be the best $30 you ever spent!
How to Avoid a Heavy Hot Tub Cover
- Remove the spa top twice weekly for 2 hours, to allow the cover to breathe.
- Avoid unzipping a spa cover or removing panels; creates voids for moisture to enter.
- Maintain proper water chemistry, and keep sanitizer at a minimum level.
- Always remove the cover for several hours after shocking the spa water.
- Patch any holes or punctures in the vinyl cover or foam barrier immediately.
- Clean and condition the exterior vinyl on your spa cover once or twice per year.
- Protect your spa cover from damage by keeping it locked, or use Hurricane straps.
In addition, buying a quality spa cover from a company you can trust, will prevent many problems with waterlogged spa covers. The “Other Guys” don’t vacuum wrap and heat seal the foam panels, and don’t use heavy duty polyester scrim and zipper.
Most importantly, hot tub covers from Hot Tub Works are warranted for 5 years against moisture in the foam core. How can we do that? Truth is, our warranty claim rate is very low, and less than 0.65% of our hot tub covers need warranty assistance.
How to Dry out a waterlogged spa cover
Once your vapor barrier has been compromised, there is not much chance of drying out the foam panel completely, but you can take it off the spa and lean it up against a wall, so that excess water drains out. There is no reason to unzip the cover and pull out the panels, since they are encased in plastic and won’t dry out anyway. Even if you remove the foam panels from their vapor barrier, very little drying of the foam will occur, even after days of drying time.
There is very little you can do once a spa cover has taken on water, except to try to find the rip, tear or puncture and make a repair, but by then it may be too late. The best thing for a waterlogged hot tub lid is to set aside $300-500, and buy a new spa cover. This time you may opt for a spa cover with denser and thicker foam or more importantly, a double-wrapped foam core.
Happy Hot Tubbin’
Hot Tub Works