Swimming Pool Blog
by Rob Cox, October 23, 2019
Automatic Pool Covers as Winter Covers?
It's an old question, but one that has little space on the poolcenter blog. Can an automatic pool cover be used as a winter pool cover? Yes. But Should an auto cover be used as a winter cover? Maybe not.
There are some drawbacks to using your expensive automatic cover all year around. Even if you are in a warm southern climate with very little snow and ice, a stock safety cover is always an easier, and cheaper option for winter use.
Stock safety covers are those rectangular sizes that are always in-stock, and they are also the cheapest safety covers to buy, a rectangle 18x36 stock safety cover prices start at $565 for mesh or $816 for solid.
Why you Should Not Use an Automatic Cover During Winter
SNOW & ICE:
Most auto cover tracks are attached to the underside of the pool coping. If the water level is not high enough, the tracks can be pulled out, or the sewn canvas edges of the cover will tear and rip, under the weight of heavy ice and snow. In northern areas, snow may melt and refreeze before you can pump it off, now you have a heavy slab of ice on your cover, which thaws on the edges to produce sharp edges that can puncture or abrade the cover material. Sharp sticks that are trapped in the ice can also puncture or abrade as the ice sheet shifts and moves.
Snow, ice and rain also displace the water in the pool, pushing it over the deep end dam wall, the tiled shelf, which can cause damage to the tile when the water freezes at that level overnight, but more importantly, it lowers the water level in the pool as the water on top of the cover pushes the water under the cover over the tiled shelf, and out the cover box drain. This lowers the water level in the pool, which is needed to support the weight of the cover, and snow and ice. A good automatic cover pump can keep rain pumped off, but it can't do anything with snow and ice, until it melts.
The sun's ultraviolet rays are degrading to fabrics, even to reinforced PVC vinyl used on automatic pool covers. If your season is 6-months long, but you use the auto cover for 12-months, you may expect the fabric to be exposed to twice as much UV radiation each year. While it may not wear out twice as fast, it definitely won't last as long as if you had it safely rolled-up on the reel all winter long. Fabric replacement on an automatic cover can cost $3000-$4000 (!) for the average sized pool. That's an expense that most people want to delay as long as possible!
Cold temperatures are also known to degrade soft materials, such as your automatic pool cover fabrics. Cold temps tends to make vinyl brittle and stiff, and with greater exposure to cold temperatures, you can expect the fabric to lose plasticizers at a greater rate, and reduce the lifespan of the fabric, and also the cable or ropes. Better to have both fabric and ropes rolled up on the reel during very cold weather, for longevity.
You are probably averse to stains on your automatic pool cover fabric. Everyone develops water stains around the center, that's altogether common and somewhat unavoidable, but winter stains are much worse. From leaves in the fall, sticks in the winter, and blooming bits during the spring, along with worms, squirrels and birds - all creates work for you, to keep the cover clean. A safety cover stays taut like a trampoline, so leaves and debris just blow-off.
When a pool freezes solid across the surface, it expands about 9%. Some of the expansion is upward, but some is outward or horizontal. If the water level is below the tiles when it freezes solid, no problem, but if water or snow on the cover raises the water level, the ice sheet can put pressure on the pool tile. This can damage the tile, cracking or popping the tile off in some areas.
And when the water level approaches the perimeter tile band around a concrete pool, which are typically 6" tall, it also reaches the level of the deep end tile shelf, the dam wall for the cover box. A very common bit of winter pool damage on pools with auto covers is loosening of several square feet of tile on the tile shelf, or dam wall.
If you Do Use an Automatic Cover During Winter
It may be too late this year for you to install a low-cost safety cover, or a solid floating winter cover on the pool. But if you do use your automatic cover during winter, consider these tips:
1. Keep an automatic cover pump in place to remove rain and snow melt as fast as possible.
2. Maintain the water level during winter, adding water as needed; keep it 1-2" below the tile.
3. Remove leaves and sticks promptly. Consider a Leaf Net if you have many autumn leaves.
4. Open the cover when snow storms or heavy rains are forecasted.
5. Clean the cover box of any leaves and be sure cover box drain is not obstructed.
No matter where you live, and what type of winter you have - my advice is to use a safety cover (mesh or solid) during the off-season, and keep your expensive automatic cover fabric and ropes safely rolled up.
Seems difficult to have two covers, one for summer, one for winter - but in the long run, it will save you money and effort