While it has been identified as a key architectural marker for the Gothic building style, the flying buttress is not just an ornamental addition in Gothic cathedrals. It was developed initially as a way to divert the horizontal forces produced by the roof vaults to the ground, through the buttresses. However, it is difficult to say with some cathedrals if the flying buttresses are added for the stylistic or for the structural reasons. Research into pre-modernistic architecture is generally lacking and it is important to decipher the building techniques of the past to be able to learn from them in the present. To discover the added value of the flying buttress the St John Cathedral in Den Bosch has been chosen as a case study because it started as a roman church without flying buttresses, but was redesigned into a Gothic cathedral with them. To discover what function this particular element holds for the St John will shed more light on the element in general.
Research has shown the flying buttresses of the St John Cathedral to be structurally necessary, though perhaps a little exaggerated for the height of the roof, by choosing for a double layer of flying buttresses. The choice for this second tier probably lies in the aesthetic of the Gothic style the cathedral is meant to fit into or in the copying of French cathedrals. The figurines on top emphasize the ornamental nature and give a special feature to this particular cathedral.