Are Helical Piles Frost Resistant?
It’s been an exceptionally hard winter in Southern Ontario. Local contractors are all too aware of how hard the cold is on foundations of all kinds. Both freezing and thawing causes potential damage to decks, fences, and small structure bases. As things begin to thaw for the last time this season, you may be wondering, how will my helical piles endure the shifting ground, and will they keep my deck level? Or did I make the right decision using helical piles for my shop foundation? In Ontario, some properties have rocky conditions as well. Are helical piles strong enough amongst large rocks and frosty shifting terrain?
Cycles of Thawing and Freezing
In recent years, our winters have seen extreme contrasting temperatures. The freeze and thaw cycles come with movement that is hard on traditional foundations. But piles are designed to resist heaving and uprooting. The lower helical blade on the bottom of the pile supports the load or full weight of the structure or deck and keeps it stable. The vertical pile has only 2 ways to move, up or down. The pile blade fixes the pile and its load from sinking further or heaving upward, acting as both a support and an anchor.
Engineers of helical piles carefully chose galvanised steel to make piles resistant to cold conditions. A piles small surface area and smooth contour gives it stability as ground moves around it. This means that it’s much less likely to be pulled out like wood or concrete.
Frost Levels in Ontario
In Ontario, frost can penetrate 48” deep. The more snow coverage early in the season, the more the ground itself can be insulated and not allow frost to push down. Multiple thaws and re-freezing also can push frost levels deeper. Therefore, choosing the right length of pile is important, and obviously it changes depending on local circumstances. The key is getting the blade below the frost line.
Rock and Helical Piles
An ancient proverb states that “a wise man builds his house on rock”. Although helical piles won’t penetrate rock on its own, it is very possible to insert a pile into rocky soil. Much depends on the depth of the rock or rocky soil. There are different installation techniques, but a specialized anchor tube can be used in certain circumstances. Because the piles stability is gaged by the torque required to place it, you can always be sure any installation into rocky conditions will be “rock solid.”
One last note about water, which in Canada will at some point be ice. Water when given the opportunity to saturate wood will ultimately break it down or rot it. Therefore, wood supports that are directly placed in concrete have a short life span. When concrete dries, it shrinks, leaving pockets around posts where water can be trapped. Helical piles prevent this as wood supports are attached to them above ground using metal brackets. There is nowhere for water to sit as its quickly drained away from wood supports.
B.R.A.G. Contracting Inc.
B.R.A.G. Contracting Inc. has been installing helical piles in all kinds of conditions for many years. If you have any questions, or if you’re wondering if helical piles could be used for your next projects, call Brandon today. Or click here to get a free no obligation quote.