Screw-in ground anchors are made with sockets to suit common square posts such as 70×70 mm, 90×90 mm and 100×100 mm, and some have U-brackets for a range of widths. Match the socket size to your post's cross-section for a firm fit. Round-post and adjustable versions are also available depending on the model.

Yes, screw-in earth anchors are typically hot-dip galvanised steel, so they resist rust when buried in permanently damp ground. The galvanised coating protects the helix and socket against soil moisture and frost for long-term outdoor use. This makes them suitable for permanent fences and garden structures as well as temporary installations.

A screw-in ground anchor is installed by turning it into the soil using a steel bar through the top holes as a lever, keeping it vertical with a spirit level as you go. No digging or concrete is needed, as the helical thread pulls the anchor down and compacts the surrounding earth for grip. Screw it in until the socket sits at the right height, then insert and fix your post. They work best in firm soil; very sandy, loose or stony ground may need a concrete-set alternative.

Load capacity depends on the anchor size and soil type, but a helical ground screw develops its holding power from the compacted earth around the helix and the depth it reaches. Longer anchors with a wider helix give greater resistance to lifting and lateral movement, which suits taller fence and gate posts. In firm, well-drained soil they provide a stable hold; in loose or waterlogged ground the holding capacity is reduced.