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Hey folks, I'm up late after my shift and worrying about my pool. I've got a mesh cover on my in-ground pool here in Maryland, and with all the rain we've been getting, there's definitely water pooling on top. I keep hearing that if this water freezes under the cover, it can push against the tile line and cause cracks. Has anyone actually experienced this? I'm trying to decide if I should invest in a pump or just let it be. My pool is about 10 years old, vinyl liner with tile at the waterline.

Hi DeckDiver, I understand your concern—it's natural to want to protect your investment. I'm in Virginia and have had a mesh cover on my pool for 5 years. I practice letting go of unnecessary stress, so I don't pump off every bit of water. That said, I do use a simple submersible pump when we get heavy rain to keep the water level manageable. I haven't had any tile damage, but I also make sure the pool water itself is properly winterized with antifreeze in the lines. **Balance is key**—don't let the cover sag with weight, but don't obsess over every puddle either.

Great question! From a physics perspective, water expanding as it freezes exerts tremendous pressure—about 9% volume increase. If water is trapped between the mesh cover and the tile line, and it freezes solid, it could theoretically stress the tiles or mortar. However, in practice, mesh covers allow some water through, which might relieve pressure. I'm in Pennsylvania and did an experiment last winter: left one side with pooled water, pumped the other. No visible cracks on either side after a mild freeze, but we only hit 20°F. **Variables:** freeze duration, tile material, and existing weaknesses. I'd recommend a pump for peace of mind, especially in a colder snap.

Thanks, both. Mila, I like your balanced approach—maybe I'm overthinking it. Gigi, your science angle makes sense. My main worry is a hard freeze like we had two years ago when it hit 10°F for a week. If the water on top freezes into a solid sheet, could it really lift or crack tiles? Has anyone seen that happen firsthand, or is it more of a 'theoretical risk' that pool companies upsell pumps for?

DeckDiver, I've spoken with a neighbor who had a crack in their coping (not tile line) after an icy winter, but they had a solid cover, not mesh. With mesh, water drains through, so it's less likely to form a thick ice sheet. **My suggestion:** observe after rain. If water sits for days, consider a pump; if it drains in a day or two, breathe easy. Stress damages more than water sometimes! Also, ensure your pool water level is below the tile line per winterizing guidelines—that's crucial.

To add data: I surveyed local pool forums and found 3 reports of tile line damage linked to frozen water under covers over 5 years—all were solid covers, not mesh. Mesh covers reduce risk because they're permeable, but if debris clogs the mesh or water pools deeply, risk increases. **Actionable tip:** Use a cover pump or even a wet/dry vac occasionally. Cost is low vs. tile repair. Also, Mid-Atlantic freeze-thaw cycles are the real culprit—repeated expansion/contraction weakens materials. So yes, it *can* happen, but mesh + minor pumping seems effective mitigation.

Appreciate the insights. Sounds like mesh covers are forgiving, but a pump is cheap insurance. I'll grab one for those deep puddles and stop losing sleep over it. Thanks for sharing your experiences—this is exactly what I needed to hear from real owners, not just sales pitches. Stay warm out there!