One of the most common questions we encounter about screw piles is:
“What happens if you hit something underground when your installing screw-piles?”
And that is precisely what this article will address.
First Things First – Soil Conditions
e.g. If you are seeking to instal DIY screw-piles by hand in a site filled with old brick or concrete footings. Though it would be possible to overcome these obstructions with pre-drilling and installation with a mini digger, it would be near impossible to do that installation by hand.
In summary, you must ensure that screw-piles are suitable for your ground conditions. It will save you a lot of time and trouble to choose the right foundation type for your soil conditions.
If you have occasional obstructions at a shallow depth you can drill through these obstructions with power tools (for DIY screw-pile jobs) or with an auger flight attached to an auger unit. This clears the path for the screw-pile to be drilled in later.
If you encounter occasional obstruction at a shallow depth you can consider digging out the obstruction. Once the obstruction is removed you can continue drilling with the screw pile.
Moving The Location
In some situations, when most of the piles have been installed successfully, if a serious obstruction is encountered it can be worth simply moving the screw-pile location further down the pre-planned fountain line, providing this does not affect the maximum limit of the span between piles. If only a small number of piles encounter serious obstructions this is often an easy way to overcome the issue.
As any contractor experienced in groundworks will tell you, it is incredibly difficult to determine what is underground 100% of the time. But understanding your ground conditions is primary to choosing the right sort of foundation for your project and determining whether screw-piles are suitable. This can be achieved by conducting a soil investigation, studying local boreholes or, for minor DIY jobs, simply taking a spade and having a dig.
Once you have concluded you have suitable ground conditions for screw-piles, should you encounter the occasional obstruction, the above solutions are what the majority of installers use to overcome them.
p.s. It goes without saying that should also locate your services and use a CAT scanner if there is any doubt before conducting any groundworks.
Disclaimer –Information in this blog does not in any way constitute building advice or guidance for private or commercial building projects.