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Side hinged garage doors are manufactured in steel, GRP and timber in the UK and for the best security we would recommend the double skinned steel hinged doors as they are nearly always manufactured with a steel or aluminium sub frame included.
When the doorset is a factory assembled doorset then the tolerances and all other aspects of the door furniture are all fitted properly and accurately, giving the best overall integrity and strength.
If you order the double skin steel hinged doors and opt for the 3 point security lokcing you will have a very secure set of garage doors. The door leaves have overlapping steel edges, making attempted forcing very hard and combined with the tight tolerances and hook type locking it would take some quite serious tools and some time to gain entry through these doors.