Fence Panel Blown Out Of Its Slots

What's happening?

This is the good outcome, oddly enough. On a fence with concrete slotted posts, the panel sits in a channel and is only held by gravity and a couple of fixings, so in a strong gust the panel is designed to be the weak point — it lifts out and the posts and foundations survive. When a panel goes and the posts stay vertical, the fence has effectively broken where you would want it to. What matters is why the panel had so little holding it. Panels blow out when they are not clipped or fixed into the slots at all, when the slot is too wide or has broken away, when the panel itself has racked and shrunk so it no longer fills the channel, or when the panel has been made much bigger a sail than it was — trellis on top, a solid privacy screen where a lapped panel used to be, or ivy across the face.

What usually causes it?

• The panel never fixed or clipped into the post slots, relying on gravity alone
• A slotted concrete post with a broken or spalled slot edge, so the channel no longer grips
• The panel frame racked, twisted or shrunk with age so it sits loose in the slot
• Rotted panel battens or frame, so the fixings pulled straight through
• Trellis, a solid screen or added boarding increasing the wind load beyond the original panel
• Ivy or climbers across the panel, turning an open fence into a solid one
• Panels a size smaller than the post spacing, packed out rather than properly fitted, so suction in a gale lifts them vertically out of the channel

When should you call a fencing and gate installer?

Call a fencing installer if the post slots are damaged, if the panel frame has racked or rotted, if more than one panel has come out, or if the fence borders a road, pavement or shared access. Repeated blow-outs along a run usually mean the panels and post spacing were never a proper match, and the fix is at that level rather than panel by panel. Also call where trellis or added boarding has increased the load — the panel is the symptom, not the cause.

What will the fencing and gate installer actually do?

• Check the panel frame for racking, rot and squareness, and the post slots for spalling and damage
• Refit or replace the panel to the correct size for the post spacing, rather than packing an undersized one
• Fix panels into the slots with clips or brackets so they cannot lift out under suction
• Repair or replace concrete posts with broken slots, or fit a capping bracket where the slot edge has gone
• Reduce added wind load — removing trellis or boarding that the fence was not built for, and cutting climbers off the face
• Check the whole run for other loose panels, and advise on panel type where a solid panel keeps failing in an exposed position