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It is difficult to give an average lifespan but it is fair to say there are some very large differences for the expectations of roller door lifespans specifically in the UK. Unlike many other countries it seems, we have taken the roller garage door to extremes in terms of popularity, mainly because it is a product which will fit almost any garage opening in some way or other. The result however and downside, is there are so many smaller companies now manufacturing roller doors with no quality checks, testing or development, simply buying the basic components to assemble and sell online as quickly as possible.
A roller door is kind of flawed in some ways, because the actual door curtain rolls around and over itself, so low quality paint finishes soon deteriorate from constant rubbing over each other. Being a product made from multiple smaller components, when the components are low quality you will find a very cheap roller door built from individual slats can very easily literally come apart within a year or 2 of installation. We hear about it all the time… The main driving mechanism, the electric motor, is actually nearly always built inside the barrel for the roller door curtain, so isn't even seen to evaluate. A cheap motor will soon burn out, especially on a larger size door.
A good quality roller garage door should last between 12 and 20 years if looked after well, maybe longer. The size, number of operations per day and exposure to harsh wind or prevailing weather will all affect the longevity. Nearly all the very popular insulated, double skinned, aluminium roller doors we see in the UK are dry running systems, so the side guides and other parts should not be lubricated, so the installation and quality is the key factor for longevity and smooth running over time.
A roller garage door is one of those products which if it isn't made well or fitted properly very quickly disintegrates as most of the components rely on each other for operation.
Buy cheap with a roller door and buy twice, or even three times in some cases.