Why is my spa cover so heavy?

Why is my spa cover so heavy?

A spa cover becomes heavy when its foam core absorbs water. The core sits inside a vapour barrier and a vinyl outer, and once those layers are compromised by unbalanced water, wear, or physical damage, the foam soaks up moisture and gains weight with every week.

In most cases a waterlogged cover cannot be restored and needs replacing. This guide covers the causes, the honest answer on drying it out, and how to stop it happening to the next one.

At Spa World^®, spa covers are the accessory we replace most often, because they do the hardest job on the spa: lifted on and off daily, baking in Australian sun, holding in heat all winter. Here is what to check when yours starts feeling like a wet mattress.

In this article:

• Why does a spa cover get heavy?
• Can you dry out a waterlogged spa cover?
• What damages the cover in the first place?
• Can vinyl damage be repaired?
• How do you fix a heavy cover?
• How long should a spa cover last?
• How to prevent waterlogging
• FAQs

Why does my spa cover get so heavy?

A spa cover gets heavy because water has penetrated the foam core. The core is the insulating heart of the cover, sealed inside a vapour barrier and a vinyl skin.

While spa covers generally weigh between 15 to 30 kg, the actual weight tends to vary depending on the size and material.

When those protective layers fail, the foam absorbs water like a sponge. A cover that once lifted easily on its lifter and now takes real effort is waterlogged, not just dirty.

Can you dry out a waterlogged spa cover?

Usually not in any lasting way. Standing the cover on its side in the sun can drain and evaporate some water, and the cover will feel lighter for a while.

The problem is that the water got in because the vapour barrier or vinyl is compromised, and drying does nothing to repair that. The foam re-soaks, and a core that has been wet is also a likely host for mould and bacteria, which no amount of sunshine removes from inside the foam.

Treat drying as a short-term measure while a replacement is ordered, not a fix. A wet core has also lost most of its insulating value, so a "dried" cover still costs you money every night it is on the spa.

How does poor water chemistry damage my spa cover?

Acidic or unbalanced spa water attacks the underside of the cover every time the spa is closed. Chemical vapour rising off the water eats at the vinyl and the vapour barrier, and once those layers thin or split, moisture reaches the foam core. Keeping pH and alkalinity balanced protects the cover as much as it protects the spa.

The same applies straight after dosing: leave the cover off for at least 45 minutes after treating the water so chemicals can gas off instead of condensing on the underside.

Can dirt and grime damage my spa cover?

Yes. Dirt, tree sap, bird droppings and UV exposure wear the vinyl outer, and worn vinyl loses its waterproofing. Once the skin is porous, moisture works into the foam core underneath. A regular clean and a vinyl protectant keep the outer supple and water-resistant, which is the cheapest insurance a cover can get.

For small tears and punctures, you can use a product like the J-B Weld LeatherWeld leather and vinyl repair kit.

What happens if my spa cover has a damaged structure?

A cover with broken internal supports sags, and a sagging cover pools rainwater on top. Pooled water finds its way through stitching and seams into the foam core, and the extra weight bows the structure further, which pools more water. Once a cover no longer sheds water off its surface, waterlogging follows quickly.

How can I fix a heavy spa cover?

Replace it. A waterlogged foam core cannot be repaired, insulates poorly, and breeds mould and bacteria inside the foam, which eventually means smells and decay above your spa water. Running a spa under a wet cover also shows up on the power bill, because the heater works against a cover that is no longer holding heat in.

The sooner a waterlogged cover is replaced, the less it costs in wasted power and the lower the risk to the spa itself.

How long should a spa cover last?

Generally, a well-maintained spa cover can last for 3–5 years, but it is recommended to replace it when signs of wear and tear start to show, such as cracks, tears, fading of the color, improper fit, or loss of insulation properties. Regular cleaning and maintenance can help prolong the lifespan of a spa cover.

How do I measure for a replacement spa cover?

To measure for a replacement spa cover, follow these steps to ensure you get the perfect fit:

• Measure the outside dimensions of your spa (not the inside edges). If you have an existing cover, you can measure that, but measuring the spa itself is best for accuracy.
• Measure each side—length and width—using a tape measure.
• Measure the corner radius. This is important because spa covers often have rounded corners.

If you don’t have a current cover, just follow the same steps directly on your spa. Accurate measurements are essential because manufacturers may change spa dimensions over time, even for the same model.

Providing the length, width, and corner radius ensures your new cover will fit correctly and offer optimal insulation. Remember, spa covers are non-refundable, so double-check your measurements before ordering.

Read our article for a step by step guide on how to measure your spa cover correctly.

How can I keep my spa cover from getting waterlogged?

Prevention is cheaper than replacement. The habits that matter:

• Keep the water balanced, and leave the cover off for at least 45 minutes after dosing
• Clean the vinyl regularly and apply a protectant
• Use a cover lifter rather than dragging the cover
• Never sit, stand or walk on the cover
• Patch holes and tears the day you notice them
• Change the spa water on schedule to keep mould and mildew down

Learn more about spa water care in the article below.

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