Speak with any Winnipeg based engineers and they will tell you that the frost line in Winnipeg can go as deep as 8 feet. Yet, many Winnipeg and Manitoba based residents and contractors are supporting their building projects on 7 to 8 foot ground anchors / screwpiles. Why do these structures end up heaving? It’s simple, the helical near the bottom of the piles are not anchored below the frost line. The soil above the frost line will move with changes in climate and moisture, whereas soil below the frost line will remain immobile.
So an 8 foot pile should work well then in Winnipeg right? Unfortunately, an 8 foot ground anchor would not guarantee that your pile is anchored below the frost line. When you look at the anatomy of a ground anchor, the blade or helical ends usually 4-6 inches from the bottom of the shaft and spans anywhere from 4 to 8 inches; this means that the pile is really anywhere from 7 foot 4 inches to 6 foot 10 inches in length.
The illustration to the right demonstrates two scenarios.
- The pile on the left is not anchored below the frost line, as a result this pile will move with the soil as it expands and contracts with climate and moisture changes.
- The second pile on the right is long enough to properly anchor below the frost line. The helical blade in this instance will anchor the pile in solid soil which is not subject to movement and will provide more than adequate resistance against the first 8 feet of soil subject to movement.
Based on the above reasoning Postech Metal Foundations Winnipeg has made the choice to only provide and install 10 foot Thermal Piles (our insulated, heavy-duty ground anchors/screw piles). Postech also offers extensions to achieve additional depth if ever required.
We could carry a 7 or 8 foot pile, but we prefer to sleep at night!
Looking for Winnipeg piling contractors you can trust? Call Postech Metal Foundations Winnipeg toll-free at 1 (855) 4-PILING (474-5464) or reach us locally at (204) 793-0653.
Live outside of Winnipeg? We most likely serve your area as well so, please do not hesitate to give us a call.