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Replacing your insulated cover isn’t cheap, but it’s something every hot tub owner has to do every so often. Age is one indicator that the cover needs changing, but there are also six other signs to look out for.
Hot tub covers have a lifespan of about 4-6 years. Signs that your cover needs to be replaced are when it becomes waterlogged and heavy, it sags in the middle, the vinyl skin is damaged, the stitching is coming apart, the straps and other parts are broken, and when the cover has a foul odor.
The initial outlay of replacing your cover is a lot, but it pays for itself over time by reducing maintenance and energy costs.
A cover’s base material makes a significant difference to its lifespan. At the end of this article, I’ll show you what to look for when purchasing a new cover to get the most bang for your buck.
1. Cover Is Waterlogged and Heavy
Water is more than 30 times more efficient than dry air at transferring heat energy. Simple foam is an excellent heat insulator if it stays dry. And manufacturers try to keep the foam dry by covering it with a waterproof skin.
The thin vinyl or the plastic skin covering a hot tub cover will crack over time, exposing the foam core. Both the foam and the skin will break down through exposure to UV rays and the chemicals you use to keep your spa water clean.
The foam is there to insulate the water from the cold air, keeping the warmth in the hot tub. The foam traps pockets of air within its cells, preventing the warm, humid air beneath the cover from meeting the colder air outside.
But this foam insulation is porous and will take on water, replacing the air in the foam as more holes open in the skin. The more water the foam takes on, the faster it will degrade and begin to fail as an insulator.
Snow and debris from plants falling onto the cover can cause irreversible damage as they puncture the skin. As the snow melts, the damaged cover will become sodden and heavy due to waterlogging.
Waterlogging may even force the cover down and into contact with the surface of the water.
2. Cover Sagging in the Middle
Cupped covers are often a sign of aging, and even if you look after the cover’s skin, the insulating foam will still give up. Sagging is an indicator that the foam is falling apart on the inside of the skin.
The average lifespan for a hot tub cover is around five years. After this time, you will see cracks appearing, stitches failing, and the foam core bending in the middle.
If your cover bows, it will lose heat. Even if the cover is still intact, you will notice your energy bills going up as the insulation fails and as you try to keep the water temperature up.
You may see that the corners of the cover are no longer touching the corners of the hot tub. This gap will allow air to circulate over the water and for steam to escape, reducing the temperature inside your spa.
As vapor escapes from a sagging cover, it takes the chemicals with it, meaning you need to use more chemicals to keep the hot tub water clean.
Towards the end of the cover’s life, cupping will also cause rainwater and condensation to pool. As the water pools in the dip, it destroys the skin material even faster and puts more strain on the stitching, which causes it to tear further.
Can I Just Replace the Foam Core Inside My Hot Tub Cover?
If your cover is over five years old, it is coming to the end of its life, and you may want to replace part or all of it. New covers are expensive, but it is possible to change out the perished foam on some older covers.
The cost of the foam is around 60-70% of the cost of the entire cover, so you can make a substantial saving from replacing a panel. Some manufacturers do offer replacement foam panels for their designs, but often these will not fit other brands of hot tub cover.
The replacement foam can also be an upgrade. Better manufacturing and grades of foam may last longer and offer better insulation. Some vinyl covers come with zippers to make swapping out the foam easier.
Plastic hot tub covers will be heat sealed, and even though the foam may have broken down, plastic covers are often too difficult to open and reseal.
3. Outer Vinyl Skin Is Torn, Cracked, or Discolored
The outer vinyl skin does more than improve the visual appearance of the hot tub while the cover is on. The vinyl seals the interior foam, protecting it from the chemicals in the water, UV from the sun, and weather damage.
The cover keeps in the heat, keeps out debris, and prevents children and pets from falling in. Cracks or tears in the vinyl casing will compromise the integrity of the entire cover. And as the cover gets older, the skin will become brittle and impossible to repair.
Through small cracks in the skin, water can make its way into the foam insulation and cause bowing. You can perform a vapor barrier repair on small holes with a polythene repair patch or, in times of desperation, duct tape.
Vinyl is considered a cheaper skin cover material. But you can also buy a marine-grade vinyl cover, which is a tough, dependable, and UV-resistant material. There are also several new fabrics making their way onto hot tub covers, such as DuraTherm, which is 3-times stronger than high-end vinyl.
Better-quality cover manufacturers will also wrap their foam cores in thick plastic. The plastic wrapping helps to ensure that no moisture can get through to the foam if the skin is damaged.
If the skin has large tears, cracks, and holes exposing the foam, you will want to replace the entire cover.
4. Stitching Is Coming Apart
Bad stitching is a common issue with hot tub covers, and they do not take long to appear. Poor stitching will pull the material apart over time as you open and close the cover. Once a stitch works free, it will not take long before it pulls out the other stitches while ripping through the skin.
If you see a broken or damaged stitch, it is worth fixing before it gets worse. You can apply duct tape to prevent the stitch from working the gap open and to help seal the hole. But for a longer-lasting result, it is better to sew up the end of the old stitch before applying the tape.
5. Straps, Locks, or Hinges Are Broken
Other weak areas are the securing straps and locks on the cover. These secure points can rust and break free from the cover, making space for heat to escape and creating safety issues for pets and children.
Hinges can either be metal or part of the fabric that makes up the skin. You can rub a little spray lubricating oil into a metal hinge to prevent rust from digging in. Metal hinges are easy to replace, but you may find that the foam interior is crumbling apart and no longer able to support the strain.
For a fabric hinge, it is worth treating the area with the same cleaning liquid you use on the plastic or vinyl skin to keep it from cracking. Duct tape is a temporary solution to strengthen the seam of the fabric hinge, but this can also lead to tears further along.
Tears along a fabric hinge less than six inches long are fixable; however, bigger rips are signs that it is time to change the whole cover.
6. Cover Smells Bad
As moisture builds up in a hot place and is never given a chance to dry, it will propagate mold and bacteria. Mold will destroy the skin of the cover from the inside out, developing cracks as it goes. And after many years of protecting your spa, the foam will have soaked up a lot of water.
The mold may not have made it to the inside of the cover and be resting on the underside, facing the water. This is easy to kill off by ensuring you have the right chemical balance in the water and using an anti-mold treatment for vinyl and plastics.
The smell is often hard to place and hard to see since it can come from deep within the cover. And if you take the cover off and leave it to one side, you may not even notice the smell.
So, when you take the cover off, leave it to dry out in the fresh warm air. You can also try unzipping a small section of the cover each time you take it out of the hot tub, giving it time to dry.
Taking off the skin will show you any mold that has been growing on the foam. But if the cover is old, you may want to avoid unzipping the cover, as you will find it difficult to get the skin back over the foam.
What to Look for When Buying a New Hot Tub Cover
The base material of a hot tub cover can make a significant difference to its strength and lifespan. Foam covers come in a range of densities, compositions, and thicknesses. The best covers are made with 100% virgin closed-cell polystyrene foam.
Recycled foam is kinder to the environment, often referred to as re-grind, and offers savings over many of the alternatives. However, re-grind is notorious for soaking up water and has issues with snow and heavy rain.
The thicker and denser the foam core, the more weight it can cope with and the more it will cost. The foam core should also be reinforced with aluminum or PVC and inserted into C-channels.
Higher-end covers will use galvanized steel reinforcements to improve the rigidity. Steel reinforced covers are a safer choice for pets and children that may sit, stand, or jump on the cover.
Newer covers also come with cover caps. These caps allow for the venting of the cover during the winter months when you drain the hot tub.