Graphical Construction Glossary >> Doors. >> Door types >> Roller Door

Roller Door

Door made out interlocking horizontal laths mounted in side tracks and fixed to an overhead horizontal drum. The rotation of the drum raises and lowers the door.

A door that is about 3m wide and the same height. These all steel rollers come in different categories and the one above is in a medium size range. It is made out of interlocking laths of roll formed galvanised steel about 1.6 to 2.0mm thick. Because of the shape and the fact that the thickness is doubled at the joints in the laths (about every 60mm or so) the door itself is fairly strong. I've seen quite a few that have resisted break in attempts from crow bars under the bottom, attacks with demolition saws and even ram raids from ordinary cars. I have found that a fold flat locking point at the bottom stops all but the most serious burglars.

The door above is of a size that it could be opened by hand, or by an electric motor. The hand mechanism is an endless chain that grips a chainwheel attached to the drum and pulling on one side of the chain raises the door and the other side lowers it.

The drum that the body of the door wraps around contain sets of heavy internal coil springs to help in raising the weight of the door. So be very careful when either fixing or removing one of these doors as there is a lot of stored energy in those springs which should be respected. Take off the spring pressure before removing one of these doors.

What we are looking at above is a pair of adjacent roller doors that are at least 7m high and about 4M wide. These doors definitely need the electric winches to pull them open. The drums are fixed to purpose built steel brackets.
The height on doors like this is known as the drop. It is possible to see from this photo and the sketch below that roller doors need extra space for the roller drum above the clear height of the opening. This extra height varies with door height, but 450mm is normal for residential garages.

What we have here is a quite small door or a shutter that is about 1.5 M wide and it has a drop of about 2M. It is there as a security measure for a small retail kiosk. It would be easily lifted by hand.

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