This is another misconception and misleading bit of information floated out there by the vinyl pool people as another way of attempting to discredit the fiberglass pool industry. I am going to supply you with some facts and truth that will dispel any of this. First, let us examine fiberglass pools strength and ductility. Fiberglass is actually about 17 times stronger than concrete, yet has the unique ability to move and bend without breaking or damaging the gelcoat interior surface. You can actually move a fiberglass pool wall panel in and out 3-5 inches in either direction with no negative affect whatsoever on the product.
I often say to people, if the earth is moving more than that, the last thing you will be worried about is the pool. Now, let’s talk about frost. Frost is an accumulation of water in the soil that freezes and expands. In order to have water present, we have to have solid around something that will hold water. Our pools are surrounded by small pea stone that is “free draining”. In other words, if you poured a gallon of water into a free draining material, it would percolate through the stone and be gone. So, if we eliminate the water, no frost can occur. It is kind of like trying to start a fire without oxygen, it simply will not happen. Consider this as well. Most building codes require footings and things subject to frost heaving to be 48 inches deep. The reason is that frost will never get that deep in this region, so the footing is protected by the depth of the earth providing an insulation and barrier for frost to get that deep. The majority of our fiberglass pools are about 48 inches or so at the shallow end. So not only is the pool set in free draining material, it also is of a minimum depth that exceeds any frost depth anyhow. Finally, consider the wide spread use of fiberglass tanks in the gasoline, oil and other industries. Thousands of fiberglass tanks are containing gasoline in the ground around the world. I am quite certain, that the government and industry would not be using fiberglass tanks because they leak. On the contrary, fiberglass is so well known for its ability to contain hazardous liquids in the earth without failure for generations to come. So now you know the facts and the truth about frost and fiberglass pools. So then next time the vinyl salesperson tries to scare you with “oh there no good up in the north with the frost”, tell them that is a bunch of baloney.