Most post supports fit square timber posts from 70×70 mm to 100×100 mm, with common sizes at 70×70, 90×90 and 100×100 mm. Many U-shaped holders are width-adjustable to accept a range of post widths, and round-post and smaller 60×60 mm versions are also available.

Yes, post supports are typically made from hot-dip galvanised steel, which resists rust and is suitable for permanent outdoor and in-ground use. Galvanised coatings protect against moisture and soil contact, making the supports durable for fences, decks and pergolas exposed to weather.

Installation depends on the type: drive-in spikes are hammered directly into the ground with a driving tool, bolt-down bases are screwed to concrete with anchor bolts, and concrete-in holders are set into a wet concrete footing. For concrete-in and bolt-down types, check the post sits plumb before the concrete cures or the bolts are fully tightened.

Fixings vary by model: many bolt-down bases include or accept anchor bolts, while concrete-in and drive-in supports usually need no separate fixings once set. The GeZu Impex range covers drive-in spikes, bolt-down bases, adjustable supports and ground anchors, with product details listing the fixings and post sizes each one suits.