A minimum of three hinges is required for fire doors and is generally advised for improved stability, reducing drooping and warping, particularly for heavy or solid wood doors. Four or more hinges could be required for taller or very heavy doors in order to spread the weight and avoid undue leverage.

When fitting double doors or French doors, please note door can bow and twist as these doors are only hinged on one side of the door. You must fit a minimum of 3 hinges per door. The qualified carpenter fitting the door should also size the door by casting there eye along the long stile of the door as the center hinge will pull out the bow in the door. Please note double door will also have a tendency to have a slight bow, this can be minimized by a qualified carpenter.