Postcrete sets firm enough to remove temporary bracing within 5 to 10 minutes of adding water. You should wait at least one hour before hanging fence panels in normal conditions, and up to two hours in cold weather. Full curing typically takes 24 hours, so avoid applying heavy loads until then. In freezing conditions, allow extra time and do not use Postcrete if frost is forecast within 24 hours of the pour.
Fast-Setting Post Concrete for Fencing and Garden Structures
Postcrete is a ready-mixed concrete specially formulated for setting posts quickly and securely. Fence posts, gate posts, washing line posts, decking supports and signage fixings all benefit from its fast-setting formula. MacBlair stocks Postcrete in 20kg bags — the standard size for domestic and light commercial fencing work — available for delivery across Northern Ireland or click and collect.
Unlike traditional concrete, there is no separate mixing required. The pre-blended mix of cement, silicates and hardeners activates on contact with water, setting firm in as little as 5 to 10 minutes. This means posts can be loaded and panels hung the same day. Postcrete is compatible with timber, metal and concrete posts alike, making it a versatile choice across a wide range of fencing and garden projects. It is worth noting that Postcrete is suited to column-shaped pours and post holes, not flat surfaces or load-bearing foundations.
For a standard 1.8m fence panel run, two bags per post is the typical guide. Gate posts carry additional hinge force and generally need a deeper, wider hole, so plan for two to three bags per gate post. Keep a spare bag on site when tackling a full fence run. Hole depth should be at least 600mm for a standard post, increasing to 750mm or more in exposed conditions or soft ground. Slope the backfill away from the post base to prevent water pooling. Postcrete also holds BES 6001 certification for responsible sourcing.
Postcrete pairs naturally with the wider fencing range at MacBlair. Pick up fence boards, gate hinges, and fence paint alongside your bags to keep everything on one order. The complete fencing category covers everything from posts and panels through to trellis, wire netting, and gate fittings.
Postcrete FAQ's
For a standard 1.8m fence panel using a 100mm x 100mm post, plan for two 20kg bags per post as a general guide. The actual amount depends on your hole dimensions, the post size, and the ground conditions. For gate posts, which carry hinge force and need wider, deeper holes, allow two to three bags per post. Always order a few extra bags rather than run short mid-job.
For a standard 1.8m fence post, dig the hole to a minimum depth of 600mm (2ft). In exposed gardens, loose or soft soil, or for taller panels, increase this to 750mm or more. A deeper hole gives the post more resistance to movement in high winds. The hole diameter should be roughly three times the width of the post to allow enough Postcrete to fill around it properly.
Yes. Postcrete works well for gate posts, but gate posts need more support than standard fence posts due to the extra loading from hinges and the gate's weight. Dig a wider and deeper hole than you would for a fence post, and use two to three 20kg bags per post. It is worth propping the post and checking it is perfectly plumb before the Postcrete begins to harden, as adjustment is not possible once it starts to set.
Postcrete is compatible with timber, metal and concrete posts. For metal posts, check that the post has an appropriate coating or treatment to protect against corrosion at the base where it sits in the concrete. For concrete posts, which are heavier than timber, plan for two to three bags per post and dig accordingly. The fast-setting formula works the same way regardless of post material, so the application method remains the same throughout.