What determines this?

[crowl]

Hello! How do we know what diameter screw piles we need? What determines this?

[keizerg]

Hello! Pile diameter selection is critical and must be based on proper load calculations - this isn't something to guess at. The diameter depends on the loads your structure will impose on the foundation, which includes the building weight, live loads (people, furniture, snow), and safety factors. Piles with a diameter of 57 or 76 mm can be installed manually and are suitable for lighter structures like decks, small sheds, or fencing. However, for high-quality installation of supports with a thicker shaft (typically 89mm, 108mm, or larger), a helical pier machine is required - these larger diameters are necessary for residential buildings, garages, or any substantial structures. One of the most serious mistakes is incorrect load calculation - installing fewer piles or using supports with a smaller diameter than required is unacceptable. Trying to save money by undersizing piles can lead to unpredictable consequences including foundation settlement, structural cracking, or collapse. The diameter also affects the blade size and configuration, which determines the pile's bearing capacity in your specific soil conditions. You should have a structural engineer or qualified foundation specialist perform load calculations and specify the correct pile diameter and spacing for your project. More information at https://construction-tip-s.blogspot....installed.html Proper sizing is essential for safety and longevity.