The screw pile industry markets hard that screw piles are cheaper than concrete. The truth is that screw piles can be used for a wide range of projects and, depending on the soil characteristics, they aren’t always cheaper.
However, here is a bold claim. Screw piles are cheaper for lightly loaded structures.
It’s a bold claim and I wrestled with myself whether or not it was true. I determined that when you zoom out and look at the big picture, it’s true for Manitobans every time. Here is why:
Screw piles for lightly loaded structures are most often cheaper than a concrete sonotube (CIP) or belled (big foot) piles.
I won’t go as far to say that screw piles will always be cheaper because some concrete companies are willing to price themselves out of business (you’ll find some in the screw pile industry as well). Also, not all concrete piles are created equal; Yes, a 6 foot deep concrete pile will support your deck but it will not resist frost heave.
Screw pile installation won’t ruin the landscaping or leave an awful mess.
The collateral damage from traditional concrete piling has a cost. This cost is often overlooked but can range from a few dollars to thousands of dollars. For some folks, the highest cost is having their yard down for repairs and not available for enjoyment.
Concrete piles often heave when lightly loaded and especially when outside a heated space.
Concrete piles under your home have a very high chance of performing as designed. However, a quick stroll through any of Winnipeg’s new developments and you can’t help but notice cracking on the front steps from heaving. You will also find a disproportionate amount of frost effected piles under unheated structures like decks and sunrooms. The reason is simple, concrete is porous and frost forces are strong.
A screw pile for a lightly loaded structure (deck, sunroom, solar farm, etc.) in contrast is small enough to be considered a non-displacement pile which translates into English as a pile with a shaft small enough that the frost forces are negligible compared to the resistance created at the helical blade. Frost heaved piles are generally very expensive to remedy and most people will just suffer along with a deck or porch they aren’t happy with.
When you consider the big picture, a screw pile of a lightly loaded structure is a no brainer. Just remember, in the same way that not all concrete piles or companies are equal, not all screw piles or screw pile companies are equal; do your research and you will ensure worry free screw pile foundation for a great value.