Cottage Lake sits in a cold-moderate climate band, which sounds mild until you think about what it does to a 40-year-old steel door twice a day. The panel contracts overnight and expands again by afternoon, and that cycle runs through the torsion spring every single day of the year. A spring rated for the weight of an original, non-insulated 1980s slab was never built to absorb decades of that swing. Add in the fact that most homes in Cottage Lake went up around 1984, when builders were still hanging single steel-panel doors on torsion springs sized for a lighter, non-insulated slab, and you've got a lot of hardware working past what it was designed for. It's not that anyone did anything wrong when the house was built - it's just that a door has a service life, and this whole area is bunched right up against the end of it at the same time.