Why do screen splines keep popping out?

The frame survives here; the spline does not

Seminole County publishes an ultimate design wind speed of 129 mph for Risk Category I structures, the category screen enclosures fall in — not the 139 mph figure commonly quoted for houses. Seminole County is not in Florida’s High-Velocity Hurricane Zone (that designation applies to Miami-Dade and Broward counties). The practical result locally: in a storm, the aluminium frame here usually survives intact and the mesh blows out of the spline channel first. That is a spline-and-mesh failure, not a frame failure, and it is why the standard post-storm job in this county is a rescreen rather than a rebuild.

Why old spline is the actual cause, more than the wind

Original spline on a 1980s–90s Winter Springs cage — and the appraiser’s own records put the median enclosure build year at 1997, with 61.2% built before 2000 — has had two, three or more decades of Central Florida summers to harden and shrink. Hardened spline sits proud of the channel instead of gripping into it, so ordinary wind, not even storm wind, walks the mesh out a little at a time. Once a homeowner notices, it is usually because a whole edge has finally let go at once.

The correct fix clears the channel completely rather than rolling new spline over old residue, and sizes the replacement spline to the actual channel rather than to a default roll.

Spline questions