Do I really need to do a soil survey

[soumitss]

Hello! Planning to install screw piles for my garden shed myself. The ground seems pretty solid. Do I really need to do a soil survey, or can I just start installing?

[hydrogenn]

Hello! I strongly advise against skipping the soil survey - it's one of the top mistakes amateurs make. Without a comprehensive geological survey, you cannot calculate the optimal pile driving depth. The pile's blades must reach dense rock and penetrate below the winter soil freezing level to properly transfer loads. If the pile bottom ends up in loose or water-saturated heaving layers, it will either subside under your shed's weight or be pushed out by frost heave. It's very difficult for non-specialists to conduct accurate surveys and interpret results correctly. You may even need laboratory testing to determine soil bearing capacity at different depths. Without understanding soil resistance, you can't properly design the foundation or calculate the required number and diameter of supports. More details here: https://how-to-build-a-foundation-correctly.blogspot.com/2025/05/4-reasons-not-to-drive-screw-piles.html I recommend commissioning geological surveys or test drilling from specialists who can provide a detailed report with soil strata diagrams, groundwater levels, and bearing capacity coefficients for correct pile selection.