Typically we write about the amazing benefits of helical screw piles. One such benefit we broadcast regularly is in how we monitor the torque during installation to ensure the capacities required are met. That’s huge when compared to the traditional poured in place concrete pile educated guessing game.
BUT… with every major advantage there is a flip-side.
With a concrete poured in place pile, if the hole doesn’t outright cave-in, concrete is typically pumped into the bore hole and that is considered reasonable.
The issue with helical screw piles is that WE KNOW. We know what the capacity of the pile is because we can understand a lot about the soil’s capacity in referencing the torque output during installation. With this knowledge we can’t simply terminate the install, that would be negligent.
The result is that one of 3 options must be chosen based on economics, timelines and efficiency:
- Extend the piles in order to install them deeper and into a suitable soil strata;
- Install additional piles so that capacities can shared; or
- Remove the pile and replace it with a larger pile.
As you may have noted, all of the options above would result in additional costs.
The major disadvantage for a reputable installer of helical screw piles is that they can’t simply provide customers with “all-in pricing”. Although helical screw piles are more economical in most circumstance, a simple pricing sheet can’t be handed out without footnotes to cover additional expenses related to undesirable and difficult to predict soil conditions.
Postech Screw Piles Manitoba and NW Ontario has installed screw piles throughout our territory and always works on behalf of customers to marry our knowledge of a general area with the selection of screw piles brought to site. If you have a geotechnical report, our ability to predict pile sizes and lengths increases exponentially. However, Manitoba Gumbo is famous because it has proven to be anything but reliable or consistent and even armed with a geotech, surprises can arise.
The good news is that most projects will go off without a hitch and the required loads will be satisfied and usually exceeded. We have found that ~85% of our customers’ project invoices reflect the exact amounts which were estimated.
Although the odd project will mean an invoice which exceeds the estimate, those who choose helical screw piles will have the peace of mind that the money invested in piling will mean a solid, problem-free foundation for generations to come.